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/c2/barrierSetC2.hpp"
  37 #include "memory/allocation.inline.hpp"
  38 #include "memory/allocation.hpp"
  39 #include "opto/ad.hpp"
  40 #include "opto/block.hpp"
  41 #include "opto/c2compiler.hpp"
  42 #include "opto/c2_MacroAssembler.hpp"
  43 #include "opto/callnode.hpp"
  44 #include "opto/cfgnode.hpp"
  45 #include "opto/locknode.hpp"
  46 #include "opto/machnode.hpp"
  47 #include "opto/node.hpp"
  48 #include "opto/optoreg.hpp"
  49 #include "opto/output.hpp"
  50 #include "opto/regalloc.hpp"
  51 #include "opto/runtime.hpp"
  52 #include "opto/subnode.hpp"
  53 #include "opto/type.hpp"
  54 #include "runtime/handles.inline.hpp"
  55 #include "runtime/sharedRuntime.hpp"
  56 #include "utilities/macros.hpp"
  57 #include "utilities/powerOfTwo.hpp"
  58 #include "utilities/xmlstream.hpp"
  59 
  60 #ifndef PRODUCT
  61 #define DEBUG_ARG(x) , x
  62 #else
  63 #define DEBUG_ARG(x)
  64 #endif
  65 
  66 //------------------------------Scheduling----------------------------------
  67 // This class contains all the information necessary to implement instruction
  68 // scheduling and bundling.
  69 class Scheduling {
  70 
  71 private:
  72   // Arena to use
  73   Arena *_arena;
  74 
  75   // Control-Flow Graph info
  76   PhaseCFG *_cfg;
  77 
  78   // Register Allocation info
  79   PhaseRegAlloc *_regalloc;
  80 
  81   // Number of nodes in the method
  82   uint _node_bundling_limit;
  83 
  84   // List of scheduled nodes. Generated in reverse order
  85   Node_List _scheduled;
  86 
  87   // List of nodes currently available for choosing for scheduling
  88   Node_List _available;
  89 
  90   // For each instruction beginning a bundle, the number of following
  91   // nodes to be bundled with it.
  92   Bundle *_node_bundling_base;
  93 
  94   // Mapping from register to Node
  95   Node_List _reg_node;
  96 
  97   // Free list for pinch nodes.
  98   Node_List _pinch_free_list;
  99 
 100   // Number of uses of this node within the containing basic block.
 101   short *_uses;
 102 
 103   // Schedulable portion of current block.  Skips Region/Phi/CreateEx up
 104   // front, branch+proj at end.  Also skips Catch/CProj (same as
 105   // branch-at-end), plus just-prior exception-throwing call.
 106   uint _bb_start, _bb_end;
 107 
 108   // Latency from the end of the basic block as scheduled
 109   unsigned short *_current_latency;
 110 
 111   // Remember the next node
 112   Node *_next_node;
 113 
 114   // Use this for an unconditional branch delay slot
 115   Node *_unconditional_delay_slot;
 116 
 117   // Pointer to a Nop
 118   MachNopNode *_nop;
 119 
 120   // Length of the current bundle, in instructions
 121   uint _bundle_instr_count;
 122 
 123   // Current Cycle number, for computing latencies and bundling
 124   uint _bundle_cycle_number;
 125 
 126   // Bundle information
 127   Pipeline_Use_Element _bundle_use_elements[resource_count];
 128   Pipeline_Use         _bundle_use;
 129 
 130   // Dump the available list
 131   void dump_available() const;
 132 
 133 public:
 134   Scheduling(Arena *arena, Compile &compile);
 135 
 136   // Destructor
 137   NOT_PRODUCT( ~Scheduling(); )
 138 
 139   // Step ahead "i" cycles
 140   void step(uint i);
 141 
 142   // Step ahead 1 cycle, and clear the bundle state (for example,
 143   // at a branch target)
 144   void step_and_clear();
 145 
 146   Bundle* node_bundling(const Node *n) {
 147     assert(valid_bundle_info(n), "oob");
 148     return (&_node_bundling_base[n->_idx]);
 149   }
 150 
 151   bool valid_bundle_info(const Node *n) const {
 152     return (_node_bundling_limit > n->_idx);
 153   }
 154 
 155   bool starts_bundle(const Node *n) const {
 156     return (_node_bundling_limit > n->_idx && _node_bundling_base[n->_idx].starts_bundle());
 157   }
 158 
 159   // Do the scheduling
 160   void DoScheduling();
 161 
 162   // Compute the register antidependencies within a basic block
 163   void ComputeRegisterAntidependencies(Block *bb);
 164   void verify_do_def( Node *n, OptoReg::Name def, const char *msg );
 165   void verify_good_schedule( Block *b, const char *msg );
 166   void anti_do_def( Block *b, Node *def, OptoReg::Name def_reg, int is_def );
 167   void anti_do_use( Block *b, Node *use, OptoReg::Name use_reg );
 168 
 169   // Add a node to the current bundle
 170   void AddNodeToBundle(Node *n, const Block *bb);
 171 
 172   // Return an integer less than, equal to, or greater than zero
 173   // if the stack offset of the first argument is respectively
 174   // less than, equal to, or greater than the second.
 175   int compare_two_spill_nodes(Node* first, Node* second);
 176 
 177   // Add a node to the list of available nodes
 178   void AddNodeToAvailableList(Node *n);
 179 
 180   // Compute the local use count for the nodes in a block, and compute
 181   // the list of instructions with no uses in the block as available
 182   void ComputeUseCount(const Block *bb);
 183 
 184   // Choose an instruction from the available list to add to the bundle
 185   Node * ChooseNodeToBundle();
 186 
 187   // See if this Node fits into the currently accumulating bundle
 188   bool NodeFitsInBundle(Node *n);
 189 
 190   // Decrement the use count for a node
 191  void DecrementUseCounts(Node *n, const Block *bb);
 192 
 193   // Garbage collect pinch nodes for reuse by other blocks.
 194   void garbage_collect_pinch_nodes();
 195   // Clean up a pinch node for reuse (helper for above).
 196   void cleanup_pinch( Node *pinch );
 197 
 198   // Information for statistics gathering
 199 #ifndef PRODUCT
 200 private:
 201   // Gather information on size of nops relative to total
 202   uint _branches, _unconditional_delays;
 203 
 204   static uint _total_nop_size, _total_method_size;
 205   static uint _total_branches, _total_unconditional_delays;
 206   static uint _total_instructions_per_bundle[Pipeline::_max_instrs_per_cycle+1];
 207 
 208 public:
 209   static void print_statistics();
 210 
 211   static void increment_instructions_per_bundle(uint i) {
 212     _total_instructions_per_bundle[i]++;
 213   }
 214 
 215   static void increment_nop_size(uint s) {
 216     _total_nop_size += s;
 217   }
 218 
 219   static void increment_method_size(uint s) {
 220     _total_method_size += s;
 221   }
 222 #endif
 223 
 224 };
 225 
 226 PhaseOutput::PhaseOutput()
 227   : Phase(Phase::Output),
 228     _code_buffer("Compile::Fill_buffer"),
 229     _first_block_size(0),
 230     _handler_table(),
 231     _inc_table(),
 232     _stub_list(),
 233     _oop_map_set(nullptr),
 234     _scratch_buffer_blob(nullptr),
 235     _scratch_locs_memory(nullptr),
 236     _scratch_const_size(-1),
 237     _in_scratch_emit_size(false),
 238     _frame_slots(0),
 239     _code_offsets(),
 240     _node_bundling_limit(0),
 241     _node_bundling_base(nullptr),
 242     _orig_pc_slot(0),
 243     _orig_pc_slot_offset_in_bytes(0),
 244     _buf_sizes(),
 245     _block(nullptr),
 246     _index(0) {
 247   C->set_output(this);
 248   if (C->stub_name() == nullptr) {
 249     _orig_pc_slot = C->fixed_slots() - (sizeof(address) / VMRegImpl::stack_slot_size);
 250   }
 251 }
 252 
 253 PhaseOutput::~PhaseOutput() {
 254   C->set_output(nullptr);
 255   if (_scratch_buffer_blob != nullptr) {
 256     BufferBlob::free(_scratch_buffer_blob);
 257   }
 258 }
 259 
 260 void PhaseOutput::perform_mach_node_analysis() {
 261   // Late barrier analysis must be done after schedule and bundle
 262   // Otherwise liveness based spilling will fail
 263   BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 264   bs->late_barrier_analysis();
 265 
 266   pd_perform_mach_node_analysis();
 267 
 268   C->print_method(CompilerPhaseType::PHASE_MACH_ANALYSIS, 3);
 269 }
 270 
 271 // Convert Nodes to instruction bits and pass off to the VM
 272 void PhaseOutput::Output() {
 273   // RootNode goes
 274   assert( C->cfg()->get_root_block()->number_of_nodes() == 0, "" );
 275 
 276   // The number of new nodes (mostly MachNop) is proportional to
 277   // the number of java calls and inner loops which are aligned.
 278   if ( C->check_node_count((NodeLimitFudgeFactor + C->java_calls()*3 +
 279                             C->inner_loops()*(OptoLoopAlignment-1)),
 280                            "out of nodes before code generation" ) ) {
 281     return;
 282   }
 283   // Make sure I can find the Start Node
 284   Block *entry = C->cfg()->get_block(1);
 285   Block *broot = C->cfg()->get_root_block();
 286 
 287   const StartNode *start = entry->head()->as_Start();
 288 
 289   // Replace StartNode with prolog
 290   MachPrologNode *prolog = new MachPrologNode();
 291   entry->map_node(prolog, 0);
 292   C->cfg()->map_node_to_block(prolog, entry);
 293   C->cfg()->unmap_node_from_block(start); // start is no longer in any block
 294 
 295   // Virtual methods need an unverified entry point
 296 
 297   if( C->is_osr_compilation() ) {
 298     if( PoisonOSREntry ) {
 299       // TODO: Should use a ShouldNotReachHereNode...
 300       C->cfg()->insert( broot, 0, new MachBreakpointNode() );
 301     }
 302   } else {
 303     if( C->method() && !C->method()->flags().is_static() ) {
 304       // Insert unvalidated entry point
 305       C->cfg()->insert( broot, 0, new MachUEPNode() );
 306     }
 307 
 308   }
 309 
 310   // Break before main entry point
 311   if ((C->method() && C->directive()->BreakAtExecuteOption) ||
 312       (OptoBreakpoint && C->is_method_compilation())       ||
 313       (OptoBreakpointOSR && C->is_osr_compilation())       ||
 314       (OptoBreakpointC2R && !C->method())                   ) {
 315     // checking for C->method() means that OptoBreakpoint does not apply to
 316     // runtime stubs or frame converters
 317     C->cfg()->insert( entry, 1, new MachBreakpointNode() );
 318   }
 319 
 320   // Insert epilogs before every return
 321   for (uint i = 0; i < C->cfg()->number_of_blocks(); i++) {
 322     Block* block = C->cfg()->get_block(i);
 323     if (!block->is_connector() && block->non_connector_successor(0) == C->cfg()->get_root_block()) { // Found a program exit point?
 324       Node* m = block->end();
 325       if (m->is_Mach() && m->as_Mach()->ideal_Opcode() != Op_Halt) {
 326         MachEpilogNode* epilog = new MachEpilogNode(m->as_Mach()->ideal_Opcode() == Op_Return);
 327         block->add_inst(epilog);
 328         C->cfg()->map_node_to_block(epilog, block);
 329       }
 330     }
 331   }
 332 
 333   // Keeper of sizing aspects
 334   _buf_sizes = BufferSizingData();
 335 
 336   // Initialize code buffer
 337   estimate_buffer_size(_buf_sizes._const);
 338   if (C->failing()) return;
 339 
 340   // Pre-compute the length of blocks and replace
 341   // long branches with short if machine supports it.
 342   // Must be done before ScheduleAndBundle due to SPARC delay slots
 343   uint* blk_starts = NEW_RESOURCE_ARRAY(uint, C->cfg()->number_of_blocks() + 1);
 344   blk_starts[0] = 0;
 345   shorten_branches(blk_starts);
 346 
 347   ScheduleAndBundle();
 348   if (C->failing()) {
 349     return;
 350   }
 351 
 352   perform_mach_node_analysis();
 353 
 354   // Complete sizing of codebuffer
 355   CodeBuffer* cb = init_buffer();
 356   if (cb == nullptr || C->failing()) {
 357     return;
 358   }
 359 
 360   BuildOopMaps();
 361 
 362   if (C->failing())  {
 363     return;
 364   }
 365 
 366   fill_buffer(cb, blk_starts);
 367 }
 368 
 369 bool PhaseOutput::need_stack_bang(int frame_size_in_bytes) const {
 370   // Determine if we need to generate a stack overflow check.
 371   // Do it if the method is not a stub function and
 372   // has java calls or has frame size > vm_page_size/8.
 373   // The debug VM checks that deoptimization doesn't trigger an
 374   // unexpected stack overflow (compiled method stack banging should
 375   // guarantee it doesn't happen) so we always need the stack bang in
 376   // a debug VM.
 377   return (C->stub_function() == nullptr &&
 378           (C->has_java_calls() || frame_size_in_bytes > (int)(os::vm_page_size())>>3
 379            DEBUG_ONLY(|| true)));
 380 }
 381 
 382 bool PhaseOutput::need_register_stack_bang() const {
 383   // Determine if we need to generate a register stack overflow check.
 384   // This is only used on architectures which have split register
 385   // and memory stacks (ie. IA64).
 386   // Bang if the method is not a stub function and has java calls
 387   return (C->stub_function() == nullptr && C->has_java_calls());
 388 }
 389 
 390 
 391 // Compute the size of first NumberOfLoopInstrToAlign instructions at the top
 392 // of a loop. When aligning a loop we need to provide enough instructions
 393 // in cpu's fetch buffer to feed decoders. The loop alignment could be
 394 // avoided if we have enough instructions in fetch buffer at the head of a loop.
 395 // By default, the size is set to 999999 by Block's constructor so that
 396 // a loop will be aligned if the size is not reset here.
 397 //
 398 // Note: Mach instructions could contain several HW instructions
 399 // so the size is estimated only.
 400 //
 401 void PhaseOutput::compute_loop_first_inst_sizes() {
 402   // The next condition is used to gate the loop alignment optimization.
 403   // Don't aligned a loop if there are enough instructions at the head of a loop
 404   // or alignment padding is larger then MaxLoopPad. By default, MaxLoopPad
 405   // is equal to OptoLoopAlignment-1 except on new Intel cpus, where it is
 406   // equal to 11 bytes which is the largest address NOP instruction.
 407   if (MaxLoopPad < OptoLoopAlignment - 1) {
 408     uint last_block = C->cfg()->number_of_blocks() - 1;
 409     for (uint i = 1; i <= last_block; i++) {
 410       Block* block = C->cfg()->get_block(i);
 411       // Check the first loop's block which requires an alignment.
 412       if (block->loop_alignment() > (uint)relocInfo::addr_unit()) {
 413         uint sum_size = 0;
 414         uint inst_cnt = NumberOfLoopInstrToAlign;
 415         inst_cnt = block->compute_first_inst_size(sum_size, inst_cnt, C->regalloc());
 416 
 417         // Check subsequent fallthrough blocks if the loop's first
 418         // block(s) does not have enough instructions.
 419         Block *nb = block;
 420         while(inst_cnt > 0 &&
 421               i < last_block &&
 422               !C->cfg()->get_block(i + 1)->has_loop_alignment() &&
 423               !nb->has_successor(block)) {
 424           i++;
 425           nb = C->cfg()->get_block(i);
 426           inst_cnt  = nb->compute_first_inst_size(sum_size, inst_cnt, C->regalloc());
 427         } // while( inst_cnt > 0 && i < last_block  )
 428 
 429         block->set_first_inst_size(sum_size);
 430       } // f( b->head()->is_Loop() )
 431     } // for( i <= last_block )
 432   } // if( MaxLoopPad < OptoLoopAlignment-1 )
 433 }
 434 
 435 // The architecture description provides short branch variants for some long
 436 // branch instructions. Replace eligible long branches with short branches.
 437 void PhaseOutput::shorten_branches(uint* blk_starts) {
 438 
 439   Compile::TracePhase tp("shorten branches", &timers[_t_shortenBranches]);
 440 
 441   // Compute size of each block, method size, and relocation information size
 442   uint nblocks  = C->cfg()->number_of_blocks();
 443 
 444   uint*      jmp_offset = NEW_RESOURCE_ARRAY(uint,nblocks);
 445   uint*      jmp_size   = NEW_RESOURCE_ARRAY(uint,nblocks);
 446   int*       jmp_nidx   = NEW_RESOURCE_ARRAY(int ,nblocks);
 447 
 448   // Collect worst case block paddings
 449   int* block_worst_case_pad = NEW_RESOURCE_ARRAY(int, nblocks);
 450   memset(block_worst_case_pad, 0, nblocks * sizeof(int));
 451 
 452   DEBUG_ONLY( uint *jmp_target = NEW_RESOURCE_ARRAY(uint,nblocks); )
 453   DEBUG_ONLY( uint *jmp_rule = NEW_RESOURCE_ARRAY(uint,nblocks); )
 454 
 455   bool has_short_branch_candidate = false;
 456 
 457   // Initialize the sizes to 0
 458   int code_size  = 0;          // Size in bytes of generated code
 459   int stub_size  = 0;          // Size in bytes of all stub entries
 460   // Size in bytes of all relocation entries, including those in local stubs.
 461   // Start with 2-bytes of reloc info for the unvalidated entry point
 462   int reloc_size = 1;          // Number of relocation entries
 463 
 464   // Make three passes.  The first computes pessimistic blk_starts,
 465   // relative jmp_offset and reloc_size information.  The second performs
 466   // short branch substitution using the pessimistic sizing.  The
 467   // third inserts nops where needed.
 468 
 469   // Step one, perform a pessimistic sizing pass.
 470   uint last_call_adr = max_juint;
 471   uint last_avoid_back_to_back_adr = max_juint;
 472   uint nop_size = (new MachNopNode())->size(C->regalloc());
 473   for (uint i = 0; i < nblocks; i++) { // For all blocks
 474     Block* block = C->cfg()->get_block(i);
 475     _block = block;
 476 
 477     // During short branch replacement, we store the relative (to blk_starts)
 478     // offset of jump in jmp_offset, rather than the absolute offset of jump.
 479     // This is so that we do not need to recompute sizes of all nodes when
 480     // we compute correct blk_starts in our next sizing pass.
 481     jmp_offset[i] = 0;
 482     jmp_size[i]   = 0;
 483     jmp_nidx[i]   = -1;
 484     DEBUG_ONLY( jmp_target[i] = 0; )
 485     DEBUG_ONLY( jmp_rule[i]   = 0; )
 486 
 487     // Sum all instruction sizes to compute block size
 488     uint last_inst = block->number_of_nodes();
 489     uint blk_size = 0;
 490     for (uint j = 0; j < last_inst; j++) {
 491       _index = j;
 492       Node* nj = block->get_node(_index);
 493       // Handle machine instruction nodes
 494       if (nj->is_Mach()) {
 495         MachNode* mach = nj->as_Mach();
 496         blk_size += (mach->alignment_required() - 1) * relocInfo::addr_unit(); // assume worst case padding
 497         reloc_size += mach->reloc();
 498         if (mach->is_MachCall()) {
 499           // add size information for trampoline stub
 500           // class CallStubImpl is platform-specific and defined in the *.ad files.
 501           stub_size  += CallStubImpl::size_call_trampoline();
 502           reloc_size += CallStubImpl::reloc_call_trampoline();
 503 
 504           MachCallNode *mcall = mach->as_MachCall();
 505           // This destination address is NOT PC-relative
 506 
 507           mcall->method_set((intptr_t)mcall->entry_point());
 508 
 509           if (mcall->is_MachCallJava() && mcall->as_MachCallJava()->_method) {
 510             stub_size  += CompiledDirectCall::to_interp_stub_size();
 511             reloc_size += CompiledDirectCall::reloc_to_interp_stub();
 512           }
 513         } else if (mach->is_MachSafePoint()) {
 514           // If call/safepoint are adjacent, account for possible
 515           // nop to disambiguate the two safepoints.
 516           // ScheduleAndBundle() can rearrange nodes in a block,
 517           // check for all offsets inside this block.
 518           if (last_call_adr >= blk_starts[i]) {
 519             blk_size += nop_size;
 520           }
 521         }
 522         if (mach->avoid_back_to_back(MachNode::AVOID_BEFORE)) {
 523           // Nop is inserted between "avoid back to back" instructions.
 524           // ScheduleAndBundle() can rearrange nodes in a block,
 525           // check for all offsets inside this block.
 526           if (last_avoid_back_to_back_adr >= blk_starts[i]) {
 527             blk_size += nop_size;
 528           }
 529         }
 530         if (mach->may_be_short_branch()) {
 531           if (!nj->is_MachBranch()) {
 532 #ifndef PRODUCT
 533             nj->dump(3);
 534 #endif
 535             Unimplemented();
 536           }
 537           assert(jmp_nidx[i] == -1, "block should have only one branch");
 538           jmp_offset[i] = blk_size;
 539           jmp_size[i]   = nj->size(C->regalloc());
 540           jmp_nidx[i]   = j;
 541           has_short_branch_candidate = true;
 542         }
 543       }
 544       blk_size += nj->size(C->regalloc());
 545       // Remember end of call offset
 546       if (nj->is_MachCall() && !nj->is_MachCallLeaf()) {
 547         last_call_adr = blk_starts[i]+blk_size;
 548       }
 549       // Remember end of avoid_back_to_back offset
 550       if (nj->is_Mach() && nj->as_Mach()->avoid_back_to_back(MachNode::AVOID_AFTER)) {
 551         last_avoid_back_to_back_adr = blk_starts[i]+blk_size;
 552       }
 553     }
 554 
 555     // When the next block starts a loop, we may insert pad NOP
 556     // instructions.  Since we cannot know our future alignment,
 557     // assume the worst.
 558     if (i < nblocks - 1) {
 559       Block* nb = C->cfg()->get_block(i + 1);
 560       int max_loop_pad = nb->code_alignment()-relocInfo::addr_unit();
 561       if (max_loop_pad > 0) {
 562         assert(is_power_of_2(max_loop_pad+relocInfo::addr_unit()), "");
 563         // Adjust last_call_adr and/or last_avoid_back_to_back_adr.
 564         // If either is the last instruction in this block, bump by
 565         // max_loop_pad in lock-step with blk_size, so sizing
 566         // calculations in subsequent blocks still can conservatively
 567         // detect that it may the last instruction in this block.
 568         if (last_call_adr == blk_starts[i]+blk_size) {
 569           last_call_adr += max_loop_pad;
 570         }
 571         if (last_avoid_back_to_back_adr == blk_starts[i]+blk_size) {
 572           last_avoid_back_to_back_adr += max_loop_pad;
 573         }
 574         blk_size += max_loop_pad;
 575         block_worst_case_pad[i + 1] = max_loop_pad;
 576       }
 577     }
 578 
 579     // Save block size; update total method size
 580     blk_starts[i+1] = blk_starts[i]+blk_size;
 581   }
 582 
 583   // Step two, replace eligible long jumps.
 584   bool progress = true;
 585   uint last_may_be_short_branch_adr = max_juint;
 586   while (has_short_branch_candidate && progress) {
 587     progress = false;
 588     has_short_branch_candidate = false;
 589     int adjust_block_start = 0;
 590     for (uint i = 0; i < nblocks; i++) {
 591       Block* block = C->cfg()->get_block(i);
 592       int idx = jmp_nidx[i];
 593       MachNode* mach = (idx == -1) ? nullptr: block->get_node(idx)->as_Mach();
 594       if (mach != nullptr && mach->may_be_short_branch()) {
 595 #ifdef ASSERT
 596         assert(jmp_size[i] > 0 && mach->is_MachBranch(), "sanity");
 597         int j;
 598         // Find the branch; ignore trailing NOPs.
 599         for (j = block->number_of_nodes()-1; j>=0; j--) {
 600           Node* n = block->get_node(j);
 601           if (!n->is_Mach() || n->as_Mach()->ideal_Opcode() != Op_Con)
 602             break;
 603         }
 604         assert(j >= 0 && j == idx && block->get_node(j) == (Node*)mach, "sanity");
 605 #endif
 606         int br_size = jmp_size[i];
 607         int br_offs = blk_starts[i] + jmp_offset[i];
 608 
 609         // This requires the TRUE branch target be in succs[0]
 610         uint bnum = block->non_connector_successor(0)->_pre_order;
 611         int offset = blk_starts[bnum] - br_offs;
 612         if (bnum > i) { // adjust following block's offset
 613           offset -= adjust_block_start;
 614         }
 615 
 616         // This block can be a loop header, account for the padding
 617         // in the previous block.
 618         int block_padding = block_worst_case_pad[i];
 619         assert(i == 0 || block_padding == 0 || br_offs >= block_padding, "Should have at least a padding on top");
 620         // In the following code a nop could be inserted before
 621         // the branch which will increase the backward distance.
 622         bool needs_padding = ((uint)(br_offs - block_padding) == last_may_be_short_branch_adr);
 623         assert(!needs_padding || jmp_offset[i] == 0, "padding only branches at the beginning of block");
 624 
 625         if (needs_padding && offset <= 0)
 626           offset -= nop_size;
 627 
 628         if (C->matcher()->is_short_branch_offset(mach->rule(), br_size, offset)) {
 629           // We've got a winner.  Replace this branch.
 630           MachNode* replacement = mach->as_MachBranch()->short_branch_version();
 631 
 632           // Update the jmp_size.
 633           int new_size = replacement->size(C->regalloc());
 634           int diff     = br_size - new_size;
 635           assert(diff >= (int)nop_size, "short_branch size should be smaller");
 636           // Conservatively take into account padding between
 637           // avoid_back_to_back branches. Previous branch could be
 638           // converted into avoid_back_to_back branch during next
 639           // rounds.
 640           if (needs_padding && replacement->avoid_back_to_back(MachNode::AVOID_BEFORE)) {
 641             jmp_offset[i] += nop_size;
 642             diff -= nop_size;
 643           }
 644           adjust_block_start += diff;
 645           block->map_node(replacement, idx);
 646           mach->subsume_by(replacement, C);
 647           mach = replacement;
 648           progress = true;
 649 
 650           jmp_size[i] = new_size;
 651           DEBUG_ONLY( jmp_target[i] = bnum; );
 652           DEBUG_ONLY( jmp_rule[i] = mach->rule(); );
 653         } else {
 654           // The jump distance is not short, try again during next iteration.
 655           has_short_branch_candidate = true;
 656         }
 657       } // (mach->may_be_short_branch())
 658       if (mach != nullptr && (mach->may_be_short_branch() ||
 659                            mach->avoid_back_to_back(MachNode::AVOID_AFTER))) {
 660         last_may_be_short_branch_adr = blk_starts[i] + jmp_offset[i] + jmp_size[i];
 661       }
 662       blk_starts[i+1] -= adjust_block_start;
 663     }
 664   }
 665 
 666 #ifdef ASSERT
 667   for (uint i = 0; i < nblocks; i++) { // For all blocks
 668     if (jmp_target[i] != 0) {
 669       int br_size = jmp_size[i];
 670       int offset = blk_starts[jmp_target[i]]-(blk_starts[i] + jmp_offset[i]);
 671       if (!C->matcher()->is_short_branch_offset(jmp_rule[i], br_size, offset)) {
 672         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]);
 673       }
 674       assert(C->matcher()->is_short_branch_offset(jmp_rule[i], br_size, offset), "Displacement too large for short jmp");
 675     }
 676   }
 677 #endif
 678 
 679   // Step 3, compute the offsets of all blocks, will be done in fill_buffer()
 680   // after ScheduleAndBundle().
 681 
 682   // ------------------
 683   // Compute size for code buffer
 684   code_size = blk_starts[nblocks];
 685 
 686   // Relocation records
 687   reloc_size += 1;              // Relo entry for exception handler
 688 
 689   // Adjust reloc_size to number of record of relocation info
 690   // Min is 2 bytes, max is probably 6 or 8, with a tax up to 25% for
 691   // a relocation index.
 692   // The CodeBuffer will expand the locs array if this estimate is too low.
 693   reloc_size *= 10 / sizeof(relocInfo);
 694 
 695   _buf_sizes._reloc = reloc_size;
 696   _buf_sizes._code  = code_size;
 697   _buf_sizes._stub  = stub_size;
 698 }
 699 
 700 //------------------------------FillLocArray-----------------------------------
 701 // Create a bit of debug info and append it to the array.  The mapping is from
 702 // Java local or expression stack to constant, register or stack-slot.  For
 703 // doubles, insert 2 mappings and return 1 (to tell the caller that the next
 704 // entry has been taken care of and caller should skip it).
 705 static LocationValue *new_loc_value( PhaseRegAlloc *ra, OptoReg::Name regnum, Location::Type l_type ) {
 706   // This should never have accepted Bad before
 707   assert(OptoReg::is_valid(regnum), "location must be valid");
 708   return (OptoReg::is_reg(regnum))
 709          ? new LocationValue(Location::new_reg_loc(l_type, OptoReg::as_VMReg(regnum)) )
 710          : new LocationValue(Location::new_stk_loc(l_type,  ra->reg2offset(regnum)));
 711 }
 712 
 713 
 714 ObjectValue*
 715 PhaseOutput::sv_for_node_id(GrowableArray<ScopeValue*> *objs, int id) {
 716   for (int i = 0; i < objs->length(); i++) {
 717     assert(objs->at(i)->is_object(), "corrupt object cache");
 718     ObjectValue* sv = (ObjectValue*) objs->at(i);
 719     if (sv->id() == id) {
 720       return sv;
 721     }
 722   }
 723   // Otherwise..
 724   return nullptr;
 725 }
 726 
 727 void PhaseOutput::set_sv_for_object_node(GrowableArray<ScopeValue*> *objs,
 728                                      ObjectValue* sv ) {
 729   assert(sv_for_node_id(objs, sv->id()) == nullptr, "Precondition");
 730   objs->append(sv);
 731 }
 732 
 733 
 734 void PhaseOutput::FillLocArray( int idx, MachSafePointNode* sfpt, Node *local,
 735                             GrowableArray<ScopeValue*> *array,
 736                             GrowableArray<ScopeValue*> *objs ) {
 737   assert( local, "use _top instead of null" );
 738   if (array->length() != idx) {
 739     assert(array->length() == idx + 1, "Unexpected array count");
 740     // Old functionality:
 741     //   return
 742     // New functionality:
 743     //   Assert if the local is not top. In product mode let the new node
 744     //   override the old entry.
 745     assert(local == C->top(), "LocArray collision");
 746     if (local == C->top()) {
 747       return;
 748     }
 749     array->pop();
 750   }
 751   const Type *t = local->bottom_type();
 752 
 753   // Is it a safepoint scalar object node?
 754   if (local->is_SafePointScalarObject()) {
 755     SafePointScalarObjectNode* spobj = local->as_SafePointScalarObject();
 756 
 757     ObjectValue* sv = (ObjectValue*) sv_for_node_id(objs, spobj->_idx);
 758     if (sv == nullptr) {
 759       ciKlass* cik = t->is_oopptr()->exact_klass();
 760       assert(cik->is_instance_klass() ||
 761              cik->is_array_klass(), "Not supported allocation.");
 762       sv = new ObjectValue(spobj->_idx,
 763                            new ConstantOopWriteValue(cik->java_mirror()->constant_encoding()));
 764       set_sv_for_object_node(objs, sv);
 765 
 766       uint first_ind = spobj->first_index(sfpt->jvms());
 767       for (uint i = 0; i < spobj->n_fields(); i++) {
 768         Node* fld_node = sfpt->in(first_ind+i);
 769         (void)FillLocArray(sv->field_values()->length(), sfpt, fld_node, sv->field_values(), objs);
 770       }
 771     }
 772     array->append(sv);
 773     return;
 774   } else if (local->is_SafePointScalarMerge()) {
 775     SafePointScalarMergeNode* smerge = local->as_SafePointScalarMerge();
 776     ObjectMergeValue* mv = (ObjectMergeValue*) sv_for_node_id(objs, smerge->_idx);
 777 
 778     if (mv == nullptr) {
 779       GrowableArray<ScopeValue*> deps;
 780 
 781       int merge_pointer_idx = smerge->merge_pointer_idx(sfpt->jvms());
 782       (void)FillLocArray(0, sfpt, sfpt->in(merge_pointer_idx), &deps, objs);
 783       assert(deps.length() == 1, "missing value");
 784 
 785       int selector_idx = smerge->selector_idx(sfpt->jvms());
 786       (void)FillLocArray(1, nullptr, sfpt->in(selector_idx), &deps, nullptr);
 787       assert(deps.length() == 2, "missing value");
 788 
 789       mv = new ObjectMergeValue(smerge->_idx, deps.at(0), deps.at(1));
 790       set_sv_for_object_node(objs, mv);
 791 
 792       for (uint i = 1; i < smerge->req(); i++) {
 793         Node* obj_node = smerge->in(i);
 794         (void)FillLocArray(mv->possible_objects()->length(), sfpt, obj_node, mv->possible_objects(), objs);
 795       }
 796     }
 797     array->append(mv);
 798     return;
 799   }
 800 
 801   // Grab the register number for the local
 802   OptoReg::Name regnum = C->regalloc()->get_reg_first(local);
 803   if( OptoReg::is_valid(regnum) ) {// Got a register/stack?
 804     // Record the double as two float registers.
 805     // The register mask for such a value always specifies two adjacent
 806     // float registers, with the lower register number even.
 807     // Normally, the allocation of high and low words to these registers
 808     // is irrelevant, because nearly all operations on register pairs
 809     // (e.g., StoreD) treat them as a single unit.
 810     // Here, we assume in addition that the words in these two registers
 811     // stored "naturally" (by operations like StoreD and double stores
 812     // within the interpreter) such that the lower-numbered register
 813     // is written to the lower memory address.  This may seem like
 814     // a machine dependency, but it is not--it is a requirement on
 815     // the author of the <arch>.ad file to ensure that, for every
 816     // even/odd double-register pair to which a double may be allocated,
 817     // the word in the even single-register is stored to the first
 818     // memory word.  (Note that register numbers are completely
 819     // arbitrary, and are not tied to any machine-level encodings.)
 820 #ifdef _LP64
 821     if( t->base() == Type::DoubleBot || t->base() == Type::DoubleCon ) {
 822       array->append(new ConstantIntValue((jint)0));
 823       array->append(new_loc_value( C->regalloc(), regnum, Location::dbl ));
 824     } else if ( t->base() == Type::Long ) {
 825       array->append(new ConstantIntValue((jint)0));
 826       array->append(new_loc_value( C->regalloc(), regnum, Location::lng ));
 827     } else if ( t->base() == Type::RawPtr ) {
 828       // jsr/ret return address which must be restored into the full
 829       // width 64-bit stack slot.
 830       array->append(new_loc_value( C->regalloc(), regnum, Location::lng ));
 831     }
 832 #else //_LP64
 833     if( t->base() == Type::DoubleBot || t->base() == Type::DoubleCon || t->base() == Type::Long ) {
 834       // Repack the double/long as two jints.
 835       // The convention the interpreter uses is that the second local
 836       // holds the first raw word of the native double representation.
 837       // This is actually reasonable, since locals and stack arrays
 838       // grow downwards in all implementations.
 839       // (If, on some machine, the interpreter's Java locals or stack
 840       // were to grow upwards, the embedded doubles would be word-swapped.)
 841       array->append(new_loc_value( C->regalloc(), OptoReg::add(regnum,1), Location::normal ));
 842       array->append(new_loc_value( C->regalloc(),              regnum   , Location::normal ));
 843     }
 844 #endif //_LP64
 845     else if( (t->base() == Type::FloatBot || t->base() == Type::FloatCon) &&
 846              OptoReg::is_reg(regnum) ) {
 847       array->append(new_loc_value( C->regalloc(), regnum, Matcher::float_in_double()
 848                                                       ? Location::float_in_dbl : Location::normal ));
 849     } else if( t->base() == Type::Int && OptoReg::is_reg(regnum) ) {
 850       array->append(new_loc_value( C->regalloc(), regnum, Matcher::int_in_long
 851                                                       ? Location::int_in_long : Location::normal ));
 852     } else if( t->base() == Type::NarrowOop ) {
 853       array->append(new_loc_value( C->regalloc(), regnum, Location::narrowoop ));
 854     } else if (t->base() == Type::VectorA || t->base() == Type::VectorS ||
 855                t->base() == Type::VectorD || t->base() == Type::VectorX ||
 856                t->base() == Type::VectorY || t->base() == Type::VectorZ) {
 857       array->append(new_loc_value( C->regalloc(), regnum, Location::vector ));
 858     } else if (C->regalloc()->is_oop(local)) {
 859       assert(t->base() == Type::OopPtr || t->base() == Type::InstPtr ||
 860              t->base() == Type::AryPtr,
 861              "Unexpected type: %s", t->msg());
 862       array->append(new_loc_value( C->regalloc(), regnum, Location::oop ));
 863     } else {
 864       assert(t->base() == Type::Int || t->base() == Type::Half ||
 865              t->base() == Type::FloatCon || t->base() == Type::FloatBot,
 866              "Unexpected type: %s", t->msg());
 867       array->append(new_loc_value( C->regalloc(), regnum, Location::normal ));
 868     }
 869     return;
 870   }
 871 
 872   // No register.  It must be constant data.
 873   switch (t->base()) {
 874     case Type::Half:              // Second half of a double
 875       ShouldNotReachHere();       // Caller should skip 2nd halves
 876       break;
 877     case Type::AnyPtr:
 878       array->append(new ConstantOopWriteValue(nullptr));
 879       break;
 880     case Type::AryPtr:
 881     case Type::InstPtr:          // fall through
 882       array->append(new ConstantOopWriteValue(t->isa_oopptr()->const_oop()->constant_encoding()));
 883       break;
 884     case Type::NarrowOop:
 885       if (t == TypeNarrowOop::NULL_PTR) {
 886         array->append(new ConstantOopWriteValue(nullptr));
 887       } else {
 888         array->append(new ConstantOopWriteValue(t->make_ptr()->isa_oopptr()->const_oop()->constant_encoding()));
 889       }
 890       break;
 891     case Type::Int:
 892       array->append(new ConstantIntValue(t->is_int()->get_con()));
 893       break;
 894     case Type::RawPtr:
 895       // A return address (T_ADDRESS).
 896       assert((intptr_t)t->is_ptr()->get_con() < (intptr_t)0x10000, "must be a valid BCI");
 897 #ifdef _LP64
 898       // Must be restored to the full-width 64-bit stack slot.
 899       array->append(new ConstantLongValue(t->is_ptr()->get_con()));
 900 #else
 901       array->append(new ConstantIntValue(t->is_ptr()->get_con()));
 902 #endif
 903       break;
 904     case Type::FloatCon: {
 905       float f = t->is_float_constant()->getf();
 906       array->append(new ConstantIntValue(jint_cast(f)));
 907       break;
 908     }
 909     case Type::DoubleCon: {
 910       jdouble d = t->is_double_constant()->getd();
 911 #ifdef _LP64
 912       array->append(new ConstantIntValue((jint)0));
 913       array->append(new ConstantDoubleValue(d));
 914 #else
 915       // Repack the double as two jints.
 916     // The convention the interpreter uses is that the second local
 917     // holds the first raw word of the native double representation.
 918     // This is actually reasonable, since locals and stack arrays
 919     // grow downwards in all implementations.
 920     // (If, on some machine, the interpreter's Java locals or stack
 921     // were to grow upwards, the embedded doubles would be word-swapped.)
 922     jlong_accessor acc;
 923     acc.long_value = jlong_cast(d);
 924     array->append(new ConstantIntValue(acc.words[1]));
 925     array->append(new ConstantIntValue(acc.words[0]));
 926 #endif
 927       break;
 928     }
 929     case Type::Long: {
 930       jlong d = t->is_long()->get_con();
 931 #ifdef _LP64
 932       array->append(new ConstantIntValue((jint)0));
 933       array->append(new ConstantLongValue(d));
 934 #else
 935       // Repack the long as two jints.
 936     // The convention the interpreter uses is that the second local
 937     // holds the first raw word of the native double representation.
 938     // This is actually reasonable, since locals and stack arrays
 939     // grow downwards in all implementations.
 940     // (If, on some machine, the interpreter's Java locals or stack
 941     // were to grow upwards, the embedded doubles would be word-swapped.)
 942     jlong_accessor acc;
 943     acc.long_value = d;
 944     array->append(new ConstantIntValue(acc.words[1]));
 945     array->append(new ConstantIntValue(acc.words[0]));
 946 #endif
 947       break;
 948     }
 949     case Type::Top:               // Add an illegal value here
 950       array->append(new LocationValue(Location()));
 951       break;
 952     default:
 953       ShouldNotReachHere();
 954       break;
 955   }
 956 }
 957 
 958 // Determine if this node starts a bundle
 959 bool PhaseOutput::starts_bundle(const Node *n) const {
 960   return (_node_bundling_limit > n->_idx &&
 961           _node_bundling_base[n->_idx].starts_bundle());
 962 }
 963 
 964 // Determine if there is a monitor that has 'ov' as its owner.
 965 bool PhaseOutput::contains_as_owner(GrowableArray<MonitorValue*> *monarray, ObjectValue *ov) const {
 966   for (int k = 0; k < monarray->length(); k++) {
 967     MonitorValue* mv = monarray->at(k);
 968     if (mv->owner() == ov) {
 969       return true;
 970     }
 971   }
 972 
 973   return false;
 974 }
 975 
 976 //--------------------------Process_OopMap_Node--------------------------------
 977 void PhaseOutput::Process_OopMap_Node(MachNode *mach, int current_offset) {
 978   // Handle special safepoint nodes for synchronization
 979   MachSafePointNode *sfn   = mach->as_MachSafePoint();
 980   MachCallNode      *mcall;
 981 
 982   int safepoint_pc_offset = current_offset;
 983   bool is_method_handle_invoke = false;
 984   bool return_oop = false;
 985   bool has_ea_local_in_scope = sfn->_has_ea_local_in_scope;
 986   bool arg_escape = false;
 987 
 988   // Add the safepoint in the DebugInfoRecorder
 989   if( !mach->is_MachCall() ) {
 990     mcall = nullptr;
 991     C->debug_info()->add_safepoint(safepoint_pc_offset, sfn->_oop_map);
 992   } else {
 993     mcall = mach->as_MachCall();
 994 
 995     // Is the call a MethodHandle call?
 996     if (mcall->is_MachCallJava()) {
 997       if (mcall->as_MachCallJava()->_method_handle_invoke) {
 998         assert(C->has_method_handle_invokes(), "must have been set during call generation");
 999         is_method_handle_invoke = true;
1000       }
1001       arg_escape = mcall->as_MachCallJava()->_arg_escape;
1002     }
1003 
1004     // Check if a call returns an object.
1005     if (mcall->returns_pointer()) {
1006       return_oop = true;
1007     }
1008     safepoint_pc_offset += mcall->ret_addr_offset();
1009     C->debug_info()->add_safepoint(safepoint_pc_offset, mcall->_oop_map);
1010   }
1011 
1012   // Loop over the JVMState list to add scope information
1013   // Do not skip safepoints with a null method, they need monitor info
1014   JVMState* youngest_jvms = sfn->jvms();
1015   int max_depth = youngest_jvms->depth();
1016 
1017   // Allocate the object pool for scalar-replaced objects -- the map from
1018   // small-integer keys (which can be recorded in the local and ostack
1019   // arrays) to descriptions of the object state.
1020   GrowableArray<ScopeValue*> *objs = new GrowableArray<ScopeValue*>();
1021 
1022   // Visit scopes from oldest to youngest.
1023   for (int depth = 1; depth <= max_depth; depth++) {
1024     JVMState* jvms = youngest_jvms->of_depth(depth);
1025     int idx;
1026     ciMethod* method = jvms->has_method() ? jvms->method() : nullptr;
1027     // Safepoints that do not have method() set only provide oop-map and monitor info
1028     // to support GC; these do not support deoptimization.
1029     int num_locs = (method == nullptr) ? 0 : jvms->loc_size();
1030     int num_exps = (method == nullptr) ? 0 : jvms->stk_size();
1031     int num_mon  = jvms->nof_monitors();
1032     assert(method == nullptr || jvms->bci() < 0 || num_locs == method->max_locals(),
1033            "JVMS local count must match that of the method");
1034 
1035     // Add Local and Expression Stack Information
1036 
1037     // Insert locals into the locarray
1038     GrowableArray<ScopeValue*> *locarray = new GrowableArray<ScopeValue*>(num_locs);
1039     for( idx = 0; idx < num_locs; idx++ ) {
1040       FillLocArray( idx, sfn, sfn->local(jvms, idx), locarray, objs );
1041     }
1042 
1043     // Insert expression stack entries into the exparray
1044     GrowableArray<ScopeValue*> *exparray = new GrowableArray<ScopeValue*>(num_exps);
1045     for( idx = 0; idx < num_exps; idx++ ) {
1046       FillLocArray( idx,  sfn, sfn->stack(jvms, idx), exparray, objs );
1047     }
1048 
1049     // Add in mappings of the monitors
1050     assert( !method ||
1051             !method->is_synchronized() ||
1052             method->is_native() ||
1053             num_mon > 0 ||
1054             !GenerateSynchronizationCode,
1055             "monitors must always exist for synchronized methods");
1056 
1057     // Build the growable array of ScopeValues for exp stack
1058     GrowableArray<MonitorValue*> *monarray = new GrowableArray<MonitorValue*>(num_mon);
1059 
1060     // Loop over monitors and insert into array
1061     for (idx = 0; idx < num_mon; idx++) {
1062       // Grab the node that defines this monitor
1063       Node* box_node = sfn->monitor_box(jvms, idx);
1064       Node* obj_node = sfn->monitor_obj(jvms, idx);
1065 
1066       // Create ScopeValue for object
1067       ScopeValue *scval = nullptr;
1068 
1069       if (obj_node->is_SafePointScalarObject()) {
1070         SafePointScalarObjectNode* spobj = obj_node->as_SafePointScalarObject();
1071         scval = PhaseOutput::sv_for_node_id(objs, spobj->_idx);
1072         if (scval == nullptr) {
1073           const Type *t = spobj->bottom_type();
1074           ciKlass* cik = t->is_oopptr()->exact_klass();
1075           assert(cik->is_instance_klass() ||
1076                  cik->is_array_klass(), "Not supported allocation.");
1077           ObjectValue* sv = new ObjectValue(spobj->_idx,
1078                                             new ConstantOopWriteValue(cik->java_mirror()->constant_encoding()));
1079           PhaseOutput::set_sv_for_object_node(objs, sv);
1080 
1081           uint first_ind = spobj->first_index(youngest_jvms);
1082           for (uint i = 0; i < spobj->n_fields(); i++) {
1083             Node* fld_node = sfn->in(first_ind+i);
1084             (void)FillLocArray(sv->field_values()->length(), sfn, fld_node, sv->field_values(), objs);
1085           }
1086           scval = sv;
1087         }
1088       } else if (obj_node->is_SafePointScalarMerge()) {
1089         SafePointScalarMergeNode* smerge = obj_node->as_SafePointScalarMerge();
1090         ObjectMergeValue* mv = (ObjectMergeValue*) sv_for_node_id(objs, smerge->_idx);
1091 
1092         if (mv == nullptr) {
1093           GrowableArray<ScopeValue*> deps;
1094 
1095           int merge_pointer_idx = smerge->merge_pointer_idx(youngest_jvms);
1096           FillLocArray(0, sfn, sfn->in(merge_pointer_idx), &deps, objs);
1097           assert(deps.length() == 1, "missing value");
1098 
1099           int selector_idx = smerge->selector_idx(youngest_jvms);
1100           FillLocArray(1, nullptr, sfn->in(selector_idx), &deps, nullptr);
1101           assert(deps.length() == 2, "missing value");
1102 
1103           mv = new ObjectMergeValue(smerge->_idx, deps.at(0), deps.at(1));
1104           set_sv_for_object_node(objs, mv);
1105 
1106           for (uint i = 1; i < smerge->req(); i++) {
1107             Node* obj_node = smerge->in(i);
1108             FillLocArray(mv->possible_objects()->length(), sfn, obj_node, mv->possible_objects(), objs);
1109           }
1110         }
1111         scval = mv;
1112       } else if (!obj_node->is_Con()) {
1113         OptoReg::Name obj_reg = C->regalloc()->get_reg_first(obj_node);
1114         if( obj_node->bottom_type()->base() == Type::NarrowOop ) {
1115           scval = new_loc_value( C->regalloc(), obj_reg, Location::narrowoop );
1116         } else {
1117           scval = new_loc_value( C->regalloc(), obj_reg, Location::oop );
1118         }
1119       } else {
1120         const TypePtr *tp = obj_node->get_ptr_type();
1121         scval = new ConstantOopWriteValue(tp->is_oopptr()->const_oop()->constant_encoding());
1122       }
1123 
1124       OptoReg::Name box_reg = BoxLockNode::reg(box_node);
1125       Location basic_lock = Location::new_stk_loc(Location::normal,C->regalloc()->reg2offset(box_reg));
1126       bool eliminated = (box_node->is_BoxLock() && box_node->as_BoxLock()->is_eliminated());
1127       monarray->append(new MonitorValue(scval, basic_lock, eliminated));
1128     }
1129 
1130     // Mark ObjectValue nodes as root nodes if they are directly
1131     // referenced in the JVMS.
1132     for (int i = 0; i < objs->length(); i++) {
1133       ScopeValue* sv = objs->at(i);
1134       if (sv->is_object_merge()) {
1135         ObjectMergeValue* merge = sv->as_ObjectMergeValue();
1136 
1137         for (int j = 0; j< merge->possible_objects()->length(); j++) {
1138           ObjectValue* ov = merge->possible_objects()->at(j)->as_ObjectValue();
1139           bool is_root = locarray->contains(ov) || exparray->contains(ov) || contains_as_owner(monarray, ov);
1140           ov->set_root(is_root);
1141         }
1142       }
1143     }
1144 
1145     // We dump the object pool first, since deoptimization reads it in first.
1146     C->debug_info()->dump_object_pool(objs);
1147 
1148     // Build first class objects to pass to scope
1149     DebugToken *locvals = C->debug_info()->create_scope_values(locarray);
1150     DebugToken *expvals = C->debug_info()->create_scope_values(exparray);
1151     DebugToken *monvals = C->debug_info()->create_monitor_values(monarray);
1152 
1153     // Make method available for all Safepoints
1154     ciMethod* scope_method = method ? method : C->method();
1155     // Describe the scope here
1156     assert(jvms->bci() >= InvocationEntryBci && jvms->bci() <= 0x10000, "must be a valid or entry BCI");
1157     assert(!jvms->should_reexecute() || depth == max_depth, "reexecute allowed only for the youngest");
1158     // Now we can describe the scope.
1159     methodHandle null_mh;
1160     bool rethrow_exception = false;
1161     C->debug_info()->describe_scope(
1162       safepoint_pc_offset,
1163       null_mh,
1164       scope_method,
1165       jvms->bci(),
1166       jvms->should_reexecute(),
1167       rethrow_exception,
1168       is_method_handle_invoke,
1169       return_oop,
1170       has_ea_local_in_scope,
1171       arg_escape,
1172       locvals,
1173       expvals,
1174       monvals
1175     );
1176   } // End jvms loop
1177 
1178   // Mark the end of the scope set.
1179   C->debug_info()->end_safepoint(safepoint_pc_offset);
1180 }
1181 
1182 
1183 
1184 // A simplified version of Process_OopMap_Node, to handle non-safepoints.
1185 class NonSafepointEmitter {
1186     Compile*  C;
1187     JVMState* _pending_jvms;
1188     int       _pending_offset;
1189 
1190     void emit_non_safepoint();
1191 
1192  public:
1193     NonSafepointEmitter(Compile* compile) {
1194       this->C = compile;
1195       _pending_jvms = nullptr;
1196       _pending_offset = 0;
1197     }
1198 
1199     void observe_instruction(Node* n, int pc_offset) {
1200       if (!C->debug_info()->recording_non_safepoints())  return;
1201 
1202       Node_Notes* nn = C->node_notes_at(n->_idx);
1203       if (nn == nullptr || nn->jvms() == nullptr)  return;
1204       if (_pending_jvms != nullptr &&
1205           _pending_jvms->same_calls_as(nn->jvms())) {
1206         // Repeated JVMS?  Stretch it up here.
1207         _pending_offset = pc_offset;
1208       } else {
1209         if (_pending_jvms != nullptr &&
1210             _pending_offset < pc_offset) {
1211           emit_non_safepoint();
1212         }
1213         _pending_jvms = nullptr;
1214         if (pc_offset > C->debug_info()->last_pc_offset()) {
1215           // This is the only way _pending_jvms can become non-null:
1216           _pending_jvms = nn->jvms();
1217           _pending_offset = pc_offset;
1218         }
1219       }
1220     }
1221 
1222     // Stay out of the way of real safepoints:
1223     void observe_safepoint(JVMState* jvms, int pc_offset) {
1224       if (_pending_jvms != nullptr &&
1225           !_pending_jvms->same_calls_as(jvms) &&
1226           _pending_offset < pc_offset) {
1227         emit_non_safepoint();
1228       }
1229       _pending_jvms = nullptr;
1230     }
1231 
1232     void flush_at_end() {
1233       if (_pending_jvms != nullptr) {
1234         emit_non_safepoint();
1235       }
1236       _pending_jvms = nullptr;
1237     }
1238 };
1239 
1240 void NonSafepointEmitter::emit_non_safepoint() {
1241   JVMState* youngest_jvms = _pending_jvms;
1242   int       pc_offset     = _pending_offset;
1243 
1244   // Clear it now:
1245   _pending_jvms = nullptr;
1246 
1247   DebugInformationRecorder* debug_info = C->debug_info();
1248   assert(debug_info->recording_non_safepoints(), "sanity");
1249 
1250   debug_info->add_non_safepoint(pc_offset);
1251   int max_depth = youngest_jvms->depth();
1252 
1253   // Visit scopes from oldest to youngest.
1254   for (int depth = 1; depth <= max_depth; depth++) {
1255     JVMState* jvms = youngest_jvms->of_depth(depth);
1256     ciMethod* method = jvms->has_method() ? jvms->method() : nullptr;
1257     assert(!jvms->should_reexecute() || depth==max_depth, "reexecute allowed only for the youngest");
1258     methodHandle null_mh;
1259     debug_info->describe_scope(pc_offset, null_mh, method, jvms->bci(), jvms->should_reexecute());
1260   }
1261 
1262   // Mark the end of the scope set.
1263   debug_info->end_non_safepoint(pc_offset);
1264 }
1265 
1266 //------------------------------init_buffer------------------------------------
1267 void PhaseOutput::estimate_buffer_size(int& const_req) {
1268 
1269   // Set the initially allocated size
1270   const_req = initial_const_capacity;
1271 
1272   // The extra spacing after the code is necessary on some platforms.
1273   // Sometimes we need to patch in a jump after the last instruction,
1274   // if the nmethod has been deoptimized.  (See 4932387, 4894843.)
1275 
1276   // Compute the byte offset where we can store the deopt pc.
1277   if (C->fixed_slots() != 0) {
1278     _orig_pc_slot_offset_in_bytes = C->regalloc()->reg2offset(OptoReg::stack2reg(_orig_pc_slot));
1279   }
1280 
1281   // Compute prolog code size
1282   _method_size = 0;
1283   _frame_slots = OptoReg::reg2stack(C->matcher()->_old_SP) + C->regalloc()->_framesize;
1284   assert(_frame_slots >= 0 && _frame_slots < 1000000, "sanity check");
1285 
1286   if (C->has_mach_constant_base_node()) {
1287     uint add_size = 0;
1288     // Fill the constant table.
1289     // Note:  This must happen before shorten_branches.
1290     for (uint i = 0; i < C->cfg()->number_of_blocks(); i++) {
1291       Block* b = C->cfg()->get_block(i);
1292 
1293       for (uint j = 0; j < b->number_of_nodes(); j++) {
1294         Node* n = b->get_node(j);
1295 
1296         // If the node is a MachConstantNode evaluate the constant
1297         // value section.
1298         if (n->is_MachConstant()) {
1299           MachConstantNode* machcon = n->as_MachConstant();
1300           machcon->eval_constant(C);
1301         } else if (n->is_Mach()) {
1302           // On Power there are more nodes that issue constants.
1303           add_size += (n->as_Mach()->ins_num_consts() * 8);
1304         }
1305       }
1306     }
1307 
1308     // Calculate the offsets of the constants and the size of the
1309     // constant table (including the padding to the next section).
1310     constant_table().calculate_offsets_and_size();
1311     const_req = constant_table().size() + add_size;
1312   }
1313 
1314   // Initialize the space for the BufferBlob used to find and verify
1315   // instruction size in MachNode::emit_size()
1316   init_scratch_buffer_blob(const_req);
1317 }
1318 
1319 CodeBuffer* PhaseOutput::init_buffer() {
1320   int stub_req  = _buf_sizes._stub;
1321   int code_req  = _buf_sizes._code;
1322   int const_req = _buf_sizes._const;
1323 
1324   int pad_req   = NativeCall::instruction_size;
1325 
1326   BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
1327   stub_req += bs->estimate_stub_size();
1328 
1329   // nmethod and CodeBuffer count stubs & constants as part of method's code.
1330   // class HandlerImpl is platform-specific and defined in the *.ad files.
1331   int exception_handler_req = HandlerImpl::size_exception_handler() + MAX_stubs_size; // add marginal slop for handler
1332   int deopt_handler_req     = HandlerImpl::size_deopt_handler()     + MAX_stubs_size; // add marginal slop for handler
1333   stub_req += MAX_stubs_size;   // ensure per-stub margin
1334   code_req += MAX_inst_size;    // ensure per-instruction margin
1335 
1336   if (StressCodeBuffers)
1337     code_req = const_req = stub_req = exception_handler_req = deopt_handler_req = 0x10;  // force expansion
1338 
1339   int total_req =
1340           const_req +
1341           code_req +
1342           pad_req +
1343           stub_req +
1344           exception_handler_req +
1345           deopt_handler_req;               // deopt handler
1346 
1347   if (C->has_method_handle_invokes())
1348     total_req += deopt_handler_req;  // deopt MH handler
1349 
1350   CodeBuffer* cb = code_buffer();
1351   cb->initialize(total_req, _buf_sizes._reloc);
1352 
1353   // Have we run out of code space?
1354   if ((cb->blob() == nullptr) || (!CompileBroker::should_compile_new_jobs())) {
1355     C->record_failure("CodeCache is full");
1356     return nullptr;
1357   }
1358   // Configure the code buffer.
1359   cb->initialize_consts_size(const_req);
1360   cb->initialize_stubs_size(stub_req);
1361   cb->initialize_oop_recorder(C->env()->oop_recorder());
1362 
1363   // fill in the nop array for bundling computations
1364   MachNode *_nop_list[Bundle::_nop_count];
1365   Bundle::initialize_nops(_nop_list);
1366 
1367   return cb;
1368 }
1369 
1370 //------------------------------fill_buffer------------------------------------
1371 void PhaseOutput::fill_buffer(CodeBuffer* cb, uint* blk_starts) {
1372   // blk_starts[] contains offsets calculated during short branches processing,
1373   // offsets should not be increased during following steps.
1374 
1375   // Compute the size of first NumberOfLoopInstrToAlign instructions at head
1376   // of a loop. It is used to determine the padding for loop alignment.
1377   Compile::TracePhase tp("fill buffer", &timers[_t_fillBuffer]);
1378 
1379   compute_loop_first_inst_sizes();
1380 
1381   // Create oopmap set.
1382   _oop_map_set = new OopMapSet();
1383 
1384   // !!!!! This preserves old handling of oopmaps for now
1385   C->debug_info()->set_oopmaps(_oop_map_set);
1386 
1387   uint nblocks  = C->cfg()->number_of_blocks();
1388   // Count and start of implicit null check instructions
1389   uint inct_cnt = 0;
1390   uint* inct_starts = NEW_RESOURCE_ARRAY(uint, nblocks+1);
1391 
1392   // Count and start of calls
1393   uint* call_returns = NEW_RESOURCE_ARRAY(uint, nblocks+1);
1394 
1395   uint  return_offset = 0;
1396   int nop_size = (new MachNopNode())->size(C->regalloc());
1397 
1398   int previous_offset = 0;
1399   int current_offset  = 0;
1400   int last_call_offset = -1;
1401   int last_avoid_back_to_back_offset = -1;
1402 #ifdef ASSERT
1403   uint* jmp_target = NEW_RESOURCE_ARRAY(uint,nblocks);
1404   uint* jmp_offset = NEW_RESOURCE_ARRAY(uint,nblocks);
1405   uint* jmp_size   = NEW_RESOURCE_ARRAY(uint,nblocks);
1406   uint* jmp_rule   = NEW_RESOURCE_ARRAY(uint,nblocks);
1407 #endif
1408 
1409   // Create an array of unused labels, one for each basic block, if printing is enabled
1410 #if defined(SUPPORT_OPTO_ASSEMBLY)
1411   int* node_offsets      = nullptr;
1412   uint node_offset_limit = C->unique();
1413 
1414   if (C->print_assembly()) {
1415     node_offsets = NEW_RESOURCE_ARRAY(int, node_offset_limit);
1416   }
1417   if (node_offsets != nullptr) {
1418     // We need to initialize. Unused array elements may contain garbage and mess up PrintOptoAssembly.
1419     memset(node_offsets, 0, node_offset_limit*sizeof(int));
1420   }
1421 #endif
1422 
1423   NonSafepointEmitter non_safepoints(C);  // emit non-safepoints lazily
1424 
1425   // Emit the constant table.
1426   if (C->has_mach_constant_base_node()) {
1427     if (!constant_table().emit(*cb)) {
1428       C->record_failure("consts section overflow");
1429       return;
1430     }
1431   }
1432 
1433   // Create an array of labels, one for each basic block
1434   Label* blk_labels = NEW_RESOURCE_ARRAY(Label, nblocks+1);
1435   for (uint i = 0; i <= nblocks; i++) {
1436     blk_labels[i].init();
1437   }
1438 
1439   // Now fill in the code buffer
1440   Node* delay_slot = nullptr;
1441   for (uint i = 0; i < nblocks; i++) {
1442     Block* block = C->cfg()->get_block(i);
1443     _block = block;
1444     Node* head = block->head();
1445 
1446     // If this block needs to start aligned (i.e, can be reached other
1447     // than by falling-thru from the previous block), then force the
1448     // start of a new bundle.
1449     if (Pipeline::requires_bundling() && starts_bundle(head)) {
1450       cb->flush_bundle(true);
1451     }
1452 
1453 #ifdef ASSERT
1454     if (!block->is_connector()) {
1455       stringStream st;
1456       block->dump_head(C->cfg(), &st);
1457       MacroAssembler(cb).block_comment(st.freeze());
1458     }
1459     jmp_target[i] = 0;
1460     jmp_offset[i] = 0;
1461     jmp_size[i]   = 0;
1462     jmp_rule[i]   = 0;
1463 #endif
1464     int blk_offset = current_offset;
1465 
1466     // Define the label at the beginning of the basic block
1467     MacroAssembler(cb).bind(blk_labels[block->_pre_order]);
1468 
1469     uint last_inst = block->number_of_nodes();
1470 
1471     // Emit block normally, except for last instruction.
1472     // Emit means "dump code bits into code buffer".
1473     for (uint j = 0; j<last_inst; j++) {
1474       _index = j;
1475 
1476       // Get the node
1477       Node* n = block->get_node(j);
1478 
1479       // See if delay slots are supported
1480       if (valid_bundle_info(n) && node_bundling(n)->used_in_unconditional_delay()) {
1481         assert(delay_slot == nullptr, "no use of delay slot node");
1482         assert(n->size(C->regalloc()) == Pipeline::instr_unit_size(), "delay slot instruction wrong size");
1483 
1484         delay_slot = n;
1485         continue;
1486       }
1487 
1488       // If this starts a new instruction group, then flush the current one
1489       // (but allow split bundles)
1490       if (Pipeline::requires_bundling() && starts_bundle(n))
1491         cb->flush_bundle(false);
1492 
1493       // Special handling for SafePoint/Call Nodes
1494       bool is_mcall = false;
1495       if (n->is_Mach()) {
1496         MachNode *mach = n->as_Mach();
1497         is_mcall = n->is_MachCall();
1498         bool is_sfn = n->is_MachSafePoint();
1499 
1500         // If this requires all previous instructions be flushed, then do so
1501         if (is_sfn || is_mcall || mach->alignment_required() != 1) {
1502           cb->flush_bundle(true);
1503           current_offset = cb->insts_size();
1504         }
1505 
1506         // A padding may be needed again since a previous instruction
1507         // could be moved to delay slot.
1508 
1509         // align the instruction if necessary
1510         int padding = mach->compute_padding(current_offset);
1511         // Make sure safepoint node for polling is distinct from a call's
1512         // return by adding a nop if needed.
1513         if (is_sfn && !is_mcall && padding == 0 && current_offset == last_call_offset) {
1514           padding = nop_size;
1515         }
1516         if (padding == 0 && mach->avoid_back_to_back(MachNode::AVOID_BEFORE) &&
1517             current_offset == last_avoid_back_to_back_offset) {
1518           // Avoid back to back some instructions.
1519           padding = nop_size;
1520         }
1521 
1522         if (padding > 0) {
1523           assert((padding % nop_size) == 0, "padding is not a multiple of NOP size");
1524           int nops_cnt = padding / nop_size;
1525           MachNode *nop = new MachNopNode(nops_cnt);
1526           block->insert_node(nop, j++);
1527           last_inst++;
1528           C->cfg()->map_node_to_block(nop, block);
1529           // Ensure enough space.
1530           cb->insts()->maybe_expand_to_ensure_remaining(MAX_inst_size);
1531           if ((cb->blob() == nullptr) || (!CompileBroker::should_compile_new_jobs())) {
1532             C->record_failure("CodeCache is full");
1533             return;
1534           }
1535           nop->emit(*cb, C->regalloc());
1536           cb->flush_bundle(true);
1537           current_offset = cb->insts_size();
1538         }
1539 
1540         bool observe_safepoint = is_sfn;
1541         // Remember the start of the last call in a basic block
1542         if (is_mcall) {
1543           MachCallNode *mcall = mach->as_MachCall();
1544 
1545           // This destination address is NOT PC-relative
1546           mcall->method_set((intptr_t)mcall->entry_point());
1547 
1548           // Save the return address
1549           call_returns[block->_pre_order] = current_offset + mcall->ret_addr_offset();
1550 
1551           observe_safepoint = mcall->guaranteed_safepoint();
1552         }
1553 
1554         // sfn will be valid whenever mcall is valid now because of inheritance
1555         if (observe_safepoint) {
1556           // Handle special safepoint nodes for synchronization
1557           if (!is_mcall) {
1558             MachSafePointNode *sfn = mach->as_MachSafePoint();
1559             // !!!!! Stubs only need an oopmap right now, so bail out
1560             if (sfn->jvms()->method() == nullptr) {
1561               // Write the oopmap directly to the code blob??!!
1562               continue;
1563             }
1564           } // End synchronization
1565 
1566           non_safepoints.observe_safepoint(mach->as_MachSafePoint()->jvms(),
1567                                            current_offset);
1568           Process_OopMap_Node(mach, current_offset);
1569         } // End if safepoint
1570 
1571           // If this is a null check, then add the start of the previous instruction to the list
1572         else if( mach->is_MachNullCheck() ) {
1573           inct_starts[inct_cnt++] = previous_offset;
1574         }
1575 
1576           // If this is a branch, then fill in the label with the target BB's label
1577         else if (mach->is_MachBranch()) {
1578           // This requires the TRUE branch target be in succs[0]
1579           uint block_num = block->non_connector_successor(0)->_pre_order;
1580 
1581           // Try to replace long branch if delay slot is not used,
1582           // it is mostly for back branches since forward branch's
1583           // distance is not updated yet.
1584           bool delay_slot_is_used = valid_bundle_info(n) &&
1585                                     C->output()->node_bundling(n)->use_unconditional_delay();
1586           if (!delay_slot_is_used && mach->may_be_short_branch()) {
1587             assert(delay_slot == nullptr, "not expecting delay slot node");
1588             int br_size = n->size(C->regalloc());
1589             int offset = blk_starts[block_num] - current_offset;
1590             if (block_num >= i) {
1591               // Current and following block's offset are not
1592               // finalized yet, adjust distance by the difference
1593               // between calculated and final offsets of current block.
1594               offset -= (blk_starts[i] - blk_offset);
1595             }
1596             // In the following code a nop could be inserted before
1597             // the branch which will increase the backward distance.
1598             bool needs_padding = (current_offset == last_avoid_back_to_back_offset);
1599             if (needs_padding && offset <= 0)
1600               offset -= nop_size;
1601 
1602             if (C->matcher()->is_short_branch_offset(mach->rule(), br_size, offset)) {
1603               // We've got a winner.  Replace this branch.
1604               MachNode* replacement = mach->as_MachBranch()->short_branch_version();
1605 
1606               // Update the jmp_size.
1607               int new_size = replacement->size(C->regalloc());
1608               assert((br_size - new_size) >= (int)nop_size, "short_branch size should be smaller");
1609               // Insert padding between avoid_back_to_back branches.
1610               if (needs_padding && replacement->avoid_back_to_back(MachNode::AVOID_BEFORE)) {
1611                 MachNode *nop = new MachNopNode();
1612                 block->insert_node(nop, j++);
1613                 C->cfg()->map_node_to_block(nop, block);
1614                 last_inst++;
1615                 nop->emit(*cb, C->regalloc());
1616                 cb->flush_bundle(true);
1617                 current_offset = cb->insts_size();
1618               }
1619 #ifdef ASSERT
1620               jmp_target[i] = block_num;
1621               jmp_offset[i] = current_offset - blk_offset;
1622               jmp_size[i]   = new_size;
1623               jmp_rule[i]   = mach->rule();
1624 #endif
1625               block->map_node(replacement, j);
1626               mach->subsume_by(replacement, C);
1627               n    = replacement;
1628               mach = replacement;
1629             }
1630           }
1631           mach->as_MachBranch()->label_set( &blk_labels[block_num], block_num );
1632         } else if (mach->ideal_Opcode() == Op_Jump) {
1633           for (uint h = 0; h < block->_num_succs; h++) {
1634             Block* succs_block = block->_succs[h];
1635             for (uint j = 1; j < succs_block->num_preds(); j++) {
1636               Node* jpn = succs_block->pred(j);
1637               if (jpn->is_JumpProj() && jpn->in(0) == mach) {
1638                 uint block_num = succs_block->non_connector()->_pre_order;
1639                 Label *blkLabel = &blk_labels[block_num];
1640                 mach->add_case_label(jpn->as_JumpProj()->proj_no(), blkLabel);
1641               }
1642             }
1643           }
1644         }
1645 #ifdef ASSERT
1646           // Check that oop-store precedes the card-mark
1647         else if (mach->ideal_Opcode() == Op_StoreCM) {
1648           uint storeCM_idx = j;
1649           int count = 0;
1650           for (uint prec = mach->req(); prec < mach->len(); prec++) {
1651             Node *oop_store = mach->in(prec);  // Precedence edge
1652             if (oop_store == nullptr) continue;
1653             count++;
1654             uint i4;
1655             for (i4 = 0; i4 < last_inst; ++i4) {
1656               if (block->get_node(i4) == oop_store) {
1657                 break;
1658               }
1659             }
1660             // Note: This test can provide a false failure if other precedence
1661             // edges have been added to the storeCMNode.
1662             assert(i4 == last_inst || i4 < storeCM_idx, "CM card-mark executes before oop-store");
1663           }
1664           assert(count > 0, "storeCM expects at least one precedence edge");
1665         }
1666 #endif
1667         else if (!n->is_Proj()) {
1668           // Remember the beginning of the previous instruction, in case
1669           // it's followed by a flag-kill and a null-check.  Happens on
1670           // Intel all the time, with add-to-memory kind of opcodes.
1671           previous_offset = current_offset;
1672         }
1673 
1674         // Not an else-if!
1675         // If this is a trap based cmp then add its offset to the list.
1676         if (mach->is_TrapBasedCheckNode()) {
1677           inct_starts[inct_cnt++] = current_offset;
1678         }
1679       }
1680 
1681       // Verify that there is sufficient space remaining
1682       cb->insts()->maybe_expand_to_ensure_remaining(MAX_inst_size);
1683       if ((cb->blob() == nullptr) || (!CompileBroker::should_compile_new_jobs())) {
1684         C->record_failure("CodeCache is full");
1685         return;
1686       }
1687 
1688       // Save the offset for the listing
1689 #if defined(SUPPORT_OPTO_ASSEMBLY)
1690       if ((node_offsets != nullptr) && (n->_idx < node_offset_limit)) {
1691         node_offsets[n->_idx] = cb->insts_size();
1692       }
1693 #endif
1694       assert(!C->failing(), "Should not reach here if failing.");
1695 
1696       // "Normal" instruction case
1697       DEBUG_ONLY(uint instr_offset = cb->insts_size());
1698       n->emit(*cb, C->regalloc());
1699       current_offset = cb->insts_size();
1700 
1701       // Above we only verified that there is enough space in the instruction section.
1702       // However, the instruction may emit stubs that cause code buffer expansion.
1703       // Bail out here if expansion failed due to a lack of code cache space.
1704       if (C->failing()) {
1705         return;
1706       }
1707 
1708       assert(!is_mcall || (call_returns[block->_pre_order] <= (uint)current_offset),
1709              "ret_addr_offset() not within emitted code");
1710 
1711 #ifdef ASSERT
1712       uint n_size = n->size(C->regalloc());
1713       if (n_size < (current_offset-instr_offset)) {
1714         MachNode* mach = n->as_Mach();
1715         n->dump();
1716         mach->dump_format(C->regalloc(), tty);
1717         tty->print_cr(" n_size (%d), current_offset (%d), instr_offset (%d)", n_size, current_offset, instr_offset);
1718         Disassembler::decode(cb->insts_begin() + instr_offset, cb->insts_begin() + current_offset + 1, tty);
1719         tty->print_cr(" ------------------- ");
1720         BufferBlob* blob = this->scratch_buffer_blob();
1721         address blob_begin = blob->content_begin();
1722         Disassembler::decode(blob_begin, blob_begin + n_size + 1, tty);
1723         assert(false, "wrong size of mach node");
1724       }
1725 #endif
1726       non_safepoints.observe_instruction(n, current_offset);
1727 
1728       // mcall is last "call" that can be a safepoint
1729       // record it so we can see if a poll will directly follow it
1730       // in which case we'll need a pad to make the PcDesc sites unique
1731       // see  5010568. This can be slightly inaccurate but conservative
1732       // in the case that return address is not actually at current_offset.
1733       // This is a small price to pay.
1734 
1735       if (is_mcall) {
1736         last_call_offset = current_offset;
1737       }
1738 
1739       if (n->is_Mach() && n->as_Mach()->avoid_back_to_back(MachNode::AVOID_AFTER)) {
1740         // Avoid back to back some instructions.
1741         last_avoid_back_to_back_offset = current_offset;
1742       }
1743 
1744       // See if this instruction has a delay slot
1745       if (valid_bundle_info(n) && node_bundling(n)->use_unconditional_delay()) {
1746         guarantee(delay_slot != nullptr, "expecting delay slot node");
1747 
1748         // Back up 1 instruction
1749         cb->set_insts_end(cb->insts_end() - Pipeline::instr_unit_size());
1750 
1751         // Save the offset for the listing
1752 #if defined(SUPPORT_OPTO_ASSEMBLY)
1753         if ((node_offsets != nullptr) && (delay_slot->_idx < node_offset_limit)) {
1754           node_offsets[delay_slot->_idx] = cb->insts_size();
1755         }
1756 #endif
1757 
1758         // Support a SafePoint in the delay slot
1759         if (delay_slot->is_MachSafePoint()) {
1760           MachNode *mach = delay_slot->as_Mach();
1761           // !!!!! Stubs only need an oopmap right now, so bail out
1762           if (!mach->is_MachCall() && mach->as_MachSafePoint()->jvms()->method() == nullptr) {
1763             // Write the oopmap directly to the code blob??!!
1764             delay_slot = nullptr;
1765             continue;
1766           }
1767 
1768           int adjusted_offset = current_offset - Pipeline::instr_unit_size();
1769           non_safepoints.observe_safepoint(mach->as_MachSafePoint()->jvms(),
1770                                            adjusted_offset);
1771           // Generate an OopMap entry
1772           Process_OopMap_Node(mach, adjusted_offset);
1773         }
1774 
1775         // Insert the delay slot instruction
1776         delay_slot->emit(*cb, C->regalloc());
1777 
1778         // Don't reuse it
1779         delay_slot = nullptr;
1780       }
1781 
1782     } // End for all instructions in block
1783 
1784     // If the next block is the top of a loop, pad this block out to align
1785     // the loop top a little. Helps prevent pipe stalls at loop back branches.
1786     if (i < nblocks-1) {
1787       Block *nb = C->cfg()->get_block(i + 1);
1788       int padding = nb->alignment_padding(current_offset);
1789       if( padding > 0 ) {
1790         MachNode *nop = new MachNopNode(padding / nop_size);
1791         block->insert_node(nop, block->number_of_nodes());
1792         C->cfg()->map_node_to_block(nop, block);
1793         nop->emit(*cb, C->regalloc());
1794         current_offset = cb->insts_size();
1795       }
1796     }
1797     // Verify that the distance for generated before forward
1798     // short branches is still valid.
1799     guarantee((int)(blk_starts[i+1] - blk_starts[i]) >= (current_offset - blk_offset), "shouldn't increase block size");
1800 
1801     // Save new block start offset
1802     blk_starts[i] = blk_offset;
1803   } // End of for all blocks
1804   blk_starts[nblocks] = current_offset;
1805 
1806   non_safepoints.flush_at_end();
1807 
1808   // Offset too large?
1809   if (C->failing())  return;
1810 
1811   // Define a pseudo-label at the end of the code
1812   MacroAssembler(cb).bind( blk_labels[nblocks] );
1813 
1814   // Compute the size of the first block
1815   _first_block_size = blk_labels[1].loc_pos() - blk_labels[0].loc_pos();
1816 
1817 #ifdef ASSERT
1818   for (uint i = 0; i < nblocks; i++) { // For all blocks
1819     if (jmp_target[i] != 0) {
1820       int br_size = jmp_size[i];
1821       int offset = blk_starts[jmp_target[i]]-(blk_starts[i] + jmp_offset[i]);
1822       if (!C->matcher()->is_short_branch_offset(jmp_rule[i], br_size, offset)) {
1823         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]);
1824         assert(false, "Displacement too large for short jmp");
1825       }
1826     }
1827   }
1828 #endif
1829 
1830   if (!cb->finalize_stubs()) {
1831     C->record_failure("CodeCache is full");
1832     return;
1833   }
1834 
1835   BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
1836   bs->emit_stubs(*cb);
1837   if (C->failing())  return;
1838 
1839   // Fill in stubs.
1840   _stub_list.emit(*cb);
1841   if (C->failing())  return;
1842 
1843 #ifndef PRODUCT
1844   // Information on the size of the method, without the extraneous code
1845   Scheduling::increment_method_size(cb->insts_size());
1846 #endif
1847 
1848   // ------------------
1849   // Fill in exception table entries.
1850   FillExceptionTables(inct_cnt, call_returns, inct_starts, blk_labels);
1851 
1852   // Only java methods have exception handlers and deopt handlers
1853   // class HandlerImpl is platform-specific and defined in the *.ad files.
1854   if (C->method()) {
1855     // Emit the exception handler code.
1856     _code_offsets.set_value(CodeOffsets::Exceptions, HandlerImpl::emit_exception_handler(*cb));
1857     if (C->failing()) {
1858       return; // CodeBuffer::expand failed
1859     }
1860     // Emit the deopt handler code.
1861     _code_offsets.set_value(CodeOffsets::Deopt, HandlerImpl::emit_deopt_handler(*cb));
1862 
1863     // Emit the MethodHandle deopt handler code (if required).
1864     if (C->has_method_handle_invokes() && !C->failing()) {
1865       // We can use the same code as for the normal deopt handler, we
1866       // just need a different entry point address.
1867       _code_offsets.set_value(CodeOffsets::DeoptMH, HandlerImpl::emit_deopt_handler(*cb));
1868     }
1869   }
1870 
1871   // One last check for failed CodeBuffer::expand:
1872   if ((cb->blob() == nullptr) || (!CompileBroker::should_compile_new_jobs())) {
1873     C->record_failure("CodeCache is full");
1874     return;
1875   }
1876 
1877 #if defined(SUPPORT_ABSTRACT_ASSEMBLY) || defined(SUPPORT_ASSEMBLY) || defined(SUPPORT_OPTO_ASSEMBLY)
1878   if (C->print_assembly()) {
1879     tty->cr();
1880     tty->print_cr("============================= C2-compiled nmethod ==============================");
1881   }
1882 #endif
1883 
1884 #if defined(SUPPORT_OPTO_ASSEMBLY)
1885   // Dump the assembly code, including basic-block numbers
1886   if (C->print_assembly()) {
1887     ttyLocker ttyl;  // keep the following output all in one block
1888     if (!VMThread::should_terminate()) {  // test this under the tty lock
1889       // print_metadata and dump_asm may safepoint which makes us loose the ttylock.
1890       // We call them first and write to a stringStream, then we retake the lock to
1891       // make sure the end tag is coherent, and that xmlStream->pop_tag is done thread safe.
1892       ResourceMark rm;
1893       stringStream method_metadata_str;
1894       if (C->method() != nullptr) {
1895         C->method()->print_metadata(&method_metadata_str);
1896       }
1897       stringStream dump_asm_str;
1898       dump_asm_on(&dump_asm_str, node_offsets, node_offset_limit);
1899 
1900       NoSafepointVerifier nsv;
1901       ttyLocker ttyl2;
1902       // This output goes directly to the tty, not the compiler log.
1903       // To enable tools to match it up with the compilation activity,
1904       // be sure to tag this tty output with the compile ID.
1905       if (xtty != nullptr) {
1906         xtty->head("opto_assembly compile_id='%d'%s", C->compile_id(),
1907                    C->is_osr_compilation() ? " compile_kind='osr'" : "");
1908       }
1909       if (C->method() != nullptr) {
1910         tty->print_cr("----------------------- MetaData before Compile_id = %d ------------------------", C->compile_id());
1911         tty->print_raw(method_metadata_str.freeze());
1912       } else if (C->stub_name() != nullptr) {
1913         tty->print_cr("----------------------------- RuntimeStub %s -------------------------------", C->stub_name());
1914       }
1915       tty->cr();
1916       tty->print_cr("------------------------ OptoAssembly for Compile_id = %d -----------------------", C->compile_id());
1917       tty->print_raw(dump_asm_str.freeze());
1918       tty->print_cr("--------------------------------------------------------------------------------");
1919       if (xtty != nullptr) {
1920         xtty->tail("opto_assembly");
1921       }
1922     }
1923   }
1924 #endif
1925 }
1926 
1927 void PhaseOutput::FillExceptionTables(uint cnt, uint *call_returns, uint *inct_starts, Label *blk_labels) {
1928   _inc_table.set_size(cnt);
1929 
1930   uint inct_cnt = 0;
1931   for (uint i = 0; i < C->cfg()->number_of_blocks(); i++) {
1932     Block* block = C->cfg()->get_block(i);
1933     Node *n = nullptr;
1934     int j;
1935 
1936     // Find the branch; ignore trailing NOPs.
1937     for (j = block->number_of_nodes() - 1; j >= 0; j--) {
1938       n = block->get_node(j);
1939       if (!n->is_Mach() || n->as_Mach()->ideal_Opcode() != Op_Con) {
1940         break;
1941       }
1942     }
1943 
1944     // If we didn't find anything, continue
1945     if (j < 0) {
1946       continue;
1947     }
1948 
1949     // Compute ExceptionHandlerTable subtable entry and add it
1950     // (skip empty blocks)
1951     if (n->is_Catch()) {
1952 
1953       // Get the offset of the return from the call
1954       uint call_return = call_returns[block->_pre_order];
1955 #ifdef ASSERT
1956       assert( call_return > 0, "no call seen for this basic block" );
1957       while (block->get_node(--j)->is_MachProj()) ;
1958       assert(block->get_node(j)->is_MachCall(), "CatchProj must follow call");
1959 #endif
1960       // last instruction is a CatchNode, find it's CatchProjNodes
1961       int nof_succs = block->_num_succs;
1962       // allocate space
1963       GrowableArray<intptr_t> handler_bcis(nof_succs);
1964       GrowableArray<intptr_t> handler_pcos(nof_succs);
1965       // iterate through all successors
1966       for (int j = 0; j < nof_succs; j++) {
1967         Block* s = block->_succs[j];
1968         bool found_p = false;
1969         for (uint k = 1; k < s->num_preds(); k++) {
1970           Node* pk = s->pred(k);
1971           if (pk->is_CatchProj() && pk->in(0) == n) {
1972             const CatchProjNode* p = pk->as_CatchProj();
1973             found_p = true;
1974             // add the corresponding handler bci & pco information
1975             if (p->_con != CatchProjNode::fall_through_index) {
1976               // p leads to an exception handler (and is not fall through)
1977               assert(s == C->cfg()->get_block(s->_pre_order), "bad numbering");
1978               // no duplicates, please
1979               if (!handler_bcis.contains(p->handler_bci())) {
1980                 uint block_num = s->non_connector()->_pre_order;
1981                 handler_bcis.append(p->handler_bci());
1982                 handler_pcos.append(blk_labels[block_num].loc_pos());
1983               }
1984             }
1985           }
1986         }
1987         assert(found_p, "no matching predecessor found");
1988         // Note:  Due to empty block removal, one block may have
1989         // several CatchProj inputs, from the same Catch.
1990       }
1991 
1992       // Set the offset of the return from the call
1993       assert(handler_bcis.find(-1) != -1, "must have default handler");
1994       _handler_table.add_subtable(call_return, &handler_bcis, nullptr, &handler_pcos);
1995       continue;
1996     }
1997 
1998     // Handle implicit null exception table updates
1999     if (n->is_MachNullCheck()) {
2000       uint block_num = block->non_connector_successor(0)->_pre_order;
2001       _inc_table.append(inct_starts[inct_cnt++], blk_labels[block_num].loc_pos());
2002       continue;
2003     }
2004     // Handle implicit exception table updates: trap instructions.
2005     if (n->is_Mach() && n->as_Mach()->is_TrapBasedCheckNode()) {
2006       uint block_num = block->non_connector_successor(0)->_pre_order;
2007       _inc_table.append(inct_starts[inct_cnt++], blk_labels[block_num].loc_pos());
2008       continue;
2009     }
2010   } // End of for all blocks fill in exception table entries
2011 }
2012 
2013 // Static Variables
2014 #ifndef PRODUCT
2015 uint Scheduling::_total_nop_size = 0;
2016 uint Scheduling::_total_method_size = 0;
2017 uint Scheduling::_total_branches = 0;
2018 uint Scheduling::_total_unconditional_delays = 0;
2019 uint Scheduling::_total_instructions_per_bundle[Pipeline::_max_instrs_per_cycle+1];
2020 #endif
2021 
2022 // Initializer for class Scheduling
2023 
2024 Scheduling::Scheduling(Arena *arena, Compile &compile)
2025         : _arena(arena),
2026           _cfg(compile.cfg()),
2027           _regalloc(compile.regalloc()),
2028           _scheduled(arena),
2029           _available(arena),
2030           _reg_node(arena),
2031           _pinch_free_list(arena),
2032           _next_node(nullptr),
2033           _bundle_instr_count(0),
2034           _bundle_cycle_number(0),
2035           _bundle_use(0, 0, resource_count, &_bundle_use_elements[0])
2036 #ifndef PRODUCT
2037         , _branches(0)
2038         , _unconditional_delays(0)
2039 #endif
2040 {
2041   // Create a MachNopNode
2042   _nop = new MachNopNode();
2043 
2044   // Now that the nops are in the array, save the count
2045   // (but allow entries for the nops)
2046   _node_bundling_limit = compile.unique();
2047   uint node_max = _regalloc->node_regs_max_index();
2048 
2049   compile.output()->set_node_bundling_limit(_node_bundling_limit);
2050 
2051   // This one is persistent within the Compile class
2052   _node_bundling_base = NEW_ARENA_ARRAY(compile.comp_arena(), Bundle, node_max);
2053 
2054   // Allocate space for fixed-size arrays
2055   _uses            = NEW_ARENA_ARRAY(arena, short,          node_max);
2056   _current_latency = NEW_ARENA_ARRAY(arena, unsigned short, node_max);
2057 
2058   // Clear the arrays
2059   for (uint i = 0; i < node_max; i++) {
2060     ::new (&_node_bundling_base[i]) Bundle();
2061   }
2062   memset(_uses,               0, node_max * sizeof(short));
2063   memset(_current_latency,    0, node_max * sizeof(unsigned short));
2064 
2065   // Clear the bundling information
2066   memcpy(_bundle_use_elements, Pipeline_Use::elaborated_elements, sizeof(Pipeline_Use::elaborated_elements));
2067 
2068   // Get the last node
2069   Block* block = _cfg->get_block(_cfg->number_of_blocks() - 1);
2070 
2071   _next_node = block->get_node(block->number_of_nodes() - 1);
2072 }
2073 
2074 #ifndef PRODUCT
2075 // Scheduling destructor
2076 Scheduling::~Scheduling() {
2077   _total_branches             += _branches;
2078   _total_unconditional_delays += _unconditional_delays;
2079 }
2080 #endif
2081 
2082 // Step ahead "i" cycles
2083 void Scheduling::step(uint i) {
2084 
2085   Bundle *bundle = node_bundling(_next_node);
2086   bundle->set_starts_bundle();
2087 
2088   // Update the bundle record, but leave the flags information alone
2089   if (_bundle_instr_count > 0) {
2090     bundle->set_instr_count(_bundle_instr_count);
2091     bundle->set_resources_used(_bundle_use.resourcesUsed());
2092   }
2093 
2094   // Update the state information
2095   _bundle_instr_count = 0;
2096   _bundle_cycle_number += i;
2097   _bundle_use.step(i);
2098 }
2099 
2100 void Scheduling::step_and_clear() {
2101   Bundle *bundle = node_bundling(_next_node);
2102   bundle->set_starts_bundle();
2103 
2104   // Update the bundle record
2105   if (_bundle_instr_count > 0) {
2106     bundle->set_instr_count(_bundle_instr_count);
2107     bundle->set_resources_used(_bundle_use.resourcesUsed());
2108 
2109     _bundle_cycle_number += 1;
2110   }
2111 
2112   // Clear the bundling information
2113   _bundle_instr_count = 0;
2114   _bundle_use.reset();
2115 
2116   memcpy(_bundle_use_elements,
2117          Pipeline_Use::elaborated_elements,
2118          sizeof(Pipeline_Use::elaborated_elements));
2119 }
2120 
2121 // Perform instruction scheduling and bundling over the sequence of
2122 // instructions in backwards order.
2123 void PhaseOutput::ScheduleAndBundle() {
2124 
2125   // Don't optimize this if it isn't a method
2126   if (!C->method())
2127     return;
2128 
2129   // Don't optimize this if scheduling is disabled
2130   if (!C->do_scheduling())
2131     return;
2132 
2133   // Scheduling code works only with pairs (8 bytes) maximum.
2134   // And when the scalable vector register is used, we may spill/unspill
2135   // the whole reg regardless of the max vector size.
2136   if (C->max_vector_size() > 8 ||
2137       (C->max_vector_size() > 0 && Matcher::supports_scalable_vector())) {
2138     return;
2139   }
2140 
2141   Compile::TracePhase tp("isched", &timers[_t_instrSched]);
2142 
2143   // Create a data structure for all the scheduling information
2144   Scheduling scheduling(Thread::current()->resource_area(), *C);
2145 
2146   // Walk backwards over each basic block, computing the needed alignment
2147   // Walk over all the basic blocks
2148   scheduling.DoScheduling();
2149 
2150 #ifndef PRODUCT
2151   if (C->trace_opto_output()) {
2152     // Buffer and print all at once
2153     ResourceMark rm;
2154     stringStream ss;
2155     ss.print("\n---- After ScheduleAndBundle ----\n");
2156     print_scheduling(&ss);
2157     tty->print("%s", ss.as_string());
2158   }
2159 #endif
2160 }
2161 
2162 #ifndef PRODUCT
2163 // Separated out so that it can be called directly from debugger
2164 void PhaseOutput::print_scheduling() {
2165   print_scheduling(tty);
2166 }
2167 
2168 void PhaseOutput::print_scheduling(outputStream* output_stream) {
2169   for (uint i = 0; i < C->cfg()->number_of_blocks(); i++) {
2170     output_stream->print("\nBB#%03d:\n", i);
2171     Block* block = C->cfg()->get_block(i);
2172     for (uint j = 0; j < block->number_of_nodes(); j++) {
2173       Node* n = block->get_node(j);
2174       OptoReg::Name reg = C->regalloc()->get_reg_first(n);
2175       output_stream->print(" %-6s ", reg >= 0 && reg < REG_COUNT ? Matcher::regName[reg] : "");
2176       n->dump("\n", false, output_stream);
2177     }
2178   }
2179 }
2180 #endif
2181 
2182 // See if this node fits into the present instruction bundle
2183 bool Scheduling::NodeFitsInBundle(Node *n) {
2184   uint n_idx = n->_idx;
2185 
2186   // If this is the unconditional delay instruction, then it fits
2187   if (n == _unconditional_delay_slot) {
2188 #ifndef PRODUCT
2189     if (_cfg->C->trace_opto_output())
2190       tty->print("#     NodeFitsInBundle [%4d]: TRUE; is in unconditional delay slot\n", n->_idx);
2191 #endif
2192     return (true);
2193   }
2194 
2195   // If the node cannot be scheduled this cycle, skip it
2196   if (_current_latency[n_idx] > _bundle_cycle_number) {
2197 #ifndef PRODUCT
2198     if (_cfg->C->trace_opto_output())
2199       tty->print("#     NodeFitsInBundle [%4d]: FALSE; latency %4d > %d\n",
2200                  n->_idx, _current_latency[n_idx], _bundle_cycle_number);
2201 #endif
2202     return (false);
2203   }
2204 
2205   const Pipeline *node_pipeline = n->pipeline();
2206 
2207   uint instruction_count = node_pipeline->instructionCount();
2208   if (node_pipeline->mayHaveNoCode() && n->size(_regalloc) == 0)
2209     instruction_count = 0;
2210   else if (node_pipeline->hasBranchDelay() && !_unconditional_delay_slot)
2211     instruction_count++;
2212 
2213   if (_bundle_instr_count + instruction_count > Pipeline::_max_instrs_per_cycle) {
2214 #ifndef PRODUCT
2215     if (_cfg->C->trace_opto_output())
2216       tty->print("#     NodeFitsInBundle [%4d]: FALSE; too many instructions: %d > %d\n",
2217                  n->_idx, _bundle_instr_count + instruction_count, Pipeline::_max_instrs_per_cycle);
2218 #endif
2219     return (false);
2220   }
2221 
2222   // Don't allow non-machine nodes to be handled this way
2223   if (!n->is_Mach() && instruction_count == 0)
2224     return (false);
2225 
2226   // See if there is any overlap
2227   uint delay = _bundle_use.full_latency(0, node_pipeline->resourceUse());
2228 
2229   if (delay > 0) {
2230 #ifndef PRODUCT
2231     if (_cfg->C->trace_opto_output())
2232       tty->print("#     NodeFitsInBundle [%4d]: FALSE; functional units overlap\n", n_idx);
2233 #endif
2234     return false;
2235   }
2236 
2237 #ifndef PRODUCT
2238   if (_cfg->C->trace_opto_output())
2239     tty->print("#     NodeFitsInBundle [%4d]:  TRUE\n", n_idx);
2240 #endif
2241 
2242   return true;
2243 }
2244 
2245 Node * Scheduling::ChooseNodeToBundle() {
2246   uint siz = _available.size();
2247 
2248   if (siz == 0) {
2249 
2250 #ifndef PRODUCT
2251     if (_cfg->C->trace_opto_output())
2252       tty->print("#   ChooseNodeToBundle: null\n");
2253 #endif
2254     return (nullptr);
2255   }
2256 
2257   // Fast path, if only 1 instruction in the bundle
2258   if (siz == 1) {
2259 #ifndef PRODUCT
2260     if (_cfg->C->trace_opto_output()) {
2261       tty->print("#   ChooseNodeToBundle (only 1): ");
2262       _available[0]->dump();
2263     }
2264 #endif
2265     return (_available[0]);
2266   }
2267 
2268   // Don't bother, if the bundle is already full
2269   if (_bundle_instr_count < Pipeline::_max_instrs_per_cycle) {
2270     for ( uint i = 0; i < siz; i++ ) {
2271       Node *n = _available[i];
2272 
2273       // Skip projections, we'll handle them another way
2274       if (n->is_Proj())
2275         continue;
2276 
2277       // This presupposed that instructions are inserted into the
2278       // available list in a legality order; i.e. instructions that
2279       // must be inserted first are at the head of the list
2280       if (NodeFitsInBundle(n)) {
2281 #ifndef PRODUCT
2282         if (_cfg->C->trace_opto_output()) {
2283           tty->print("#   ChooseNodeToBundle: ");
2284           n->dump();
2285         }
2286 #endif
2287         return (n);
2288       }
2289     }
2290   }
2291 
2292   // Nothing fits in this bundle, choose the highest priority
2293 #ifndef PRODUCT
2294   if (_cfg->C->trace_opto_output()) {
2295     tty->print("#   ChooseNodeToBundle: ");
2296     _available[0]->dump();
2297   }
2298 #endif
2299 
2300   return _available[0];
2301 }
2302 
2303 int Scheduling::compare_two_spill_nodes(Node* first, Node* second) {
2304   assert(first->is_MachSpillCopy() && second->is_MachSpillCopy(), "");
2305 
2306   OptoReg::Name first_src_lo = _regalloc->get_reg_first(first->in(1));
2307   OptoReg::Name first_dst_lo = _regalloc->get_reg_first(first);
2308   OptoReg::Name second_src_lo = _regalloc->get_reg_first(second->in(1));
2309   OptoReg::Name second_dst_lo = _regalloc->get_reg_first(second);
2310 
2311   // Comparison between stack -> reg and stack -> reg
2312   if (OptoReg::is_stack(first_src_lo) && OptoReg::is_stack(second_src_lo) &&
2313       OptoReg::is_reg(first_dst_lo) && OptoReg::is_reg(second_dst_lo)) {
2314     return _regalloc->reg2offset(first_src_lo) - _regalloc->reg2offset(second_src_lo);
2315   }
2316 
2317   // Comparison between reg -> stack and reg -> stack
2318   if (OptoReg::is_stack(first_dst_lo) && OptoReg::is_stack(second_dst_lo) &&
2319       OptoReg::is_reg(first_src_lo) && OptoReg::is_reg(second_src_lo)) {
2320     return _regalloc->reg2offset(first_dst_lo) - _regalloc->reg2offset(second_dst_lo);
2321   }
2322 
2323   return 0; // Not comparable
2324 }
2325 
2326 void Scheduling::AddNodeToAvailableList(Node *n) {
2327   assert( !n->is_Proj(), "projections never directly made available" );
2328 #ifndef PRODUCT
2329   if (_cfg->C->trace_opto_output()) {
2330     tty->print("#   AddNodeToAvailableList: ");
2331     n->dump();
2332   }
2333 #endif
2334 
2335   int latency = _current_latency[n->_idx];
2336 
2337   // Insert in latency order (insertion sort). If two MachSpillCopyNodes
2338   // for stack spilling or unspilling have the same latency, we sort
2339   // them in the order of stack offset. Some ports (e.g. aarch64) may also
2340   // have more opportunities to do ld/st merging
2341   uint i;
2342   for (i = 0; i < _available.size(); i++) {
2343     if (_current_latency[_available[i]->_idx] > latency) {
2344       break;
2345     } else if (_current_latency[_available[i]->_idx] == latency &&
2346                n->is_MachSpillCopy() && _available[i]->is_MachSpillCopy() &&
2347                compare_two_spill_nodes(n, _available[i]) > 0) {
2348       break;
2349     }
2350   }
2351 
2352   // Special Check for compares following branches
2353   if( n->is_Mach() && _scheduled.size() > 0 ) {
2354     int op = n->as_Mach()->ideal_Opcode();
2355     Node *last = _scheduled[0];
2356     if( last->is_MachIf() && last->in(1) == n &&
2357         ( op == Op_CmpI ||
2358           op == Op_CmpU ||
2359           op == Op_CmpUL ||
2360           op == Op_CmpP ||
2361           op == Op_CmpF ||
2362           op == Op_CmpD ||
2363           op == Op_CmpL ) ) {
2364 
2365       // Recalculate position, moving to front of same latency
2366       for ( i=0 ; i < _available.size(); i++ )
2367         if (_current_latency[_available[i]->_idx] >= latency)
2368           break;
2369     }
2370   }
2371 
2372   // Insert the node in the available list
2373   _available.insert(i, n);
2374 
2375 #ifndef PRODUCT
2376   if (_cfg->C->trace_opto_output())
2377     dump_available();
2378 #endif
2379 }
2380 
2381 void Scheduling::DecrementUseCounts(Node *n, const Block *bb) {
2382   for ( uint i=0; i < n->len(); i++ ) {
2383     Node *def = n->in(i);
2384     if (!def) continue;
2385     if( def->is_Proj() )        // If this is a machine projection, then
2386       def = def->in(0);         // propagate usage thru to the base instruction
2387 
2388     if(_cfg->get_block_for_node(def) != bb) { // Ignore if not block-local
2389       continue;
2390     }
2391 
2392     // Compute the latency
2393     uint l = _bundle_cycle_number + n->latency(i);
2394     if (_current_latency[def->_idx] < l)
2395       _current_latency[def->_idx] = l;
2396 
2397     // If this does not have uses then schedule it
2398     if ((--_uses[def->_idx]) == 0)
2399       AddNodeToAvailableList(def);
2400   }
2401 }
2402 
2403 void Scheduling::AddNodeToBundle(Node *n, const Block *bb) {
2404 #ifndef PRODUCT
2405   if (_cfg->C->trace_opto_output()) {
2406     tty->print("#   AddNodeToBundle: ");
2407     n->dump();
2408   }
2409 #endif
2410 
2411   // Remove this from the available list
2412   uint i;
2413   for (i = 0; i < _available.size(); i++)
2414     if (_available[i] == n)
2415       break;
2416   assert(i < _available.size(), "entry in _available list not found");
2417   _available.remove(i);
2418 
2419   // See if this fits in the current bundle
2420   const Pipeline *node_pipeline = n->pipeline();
2421   const Pipeline_Use& node_usage = node_pipeline->resourceUse();
2422 
2423   // Check for instructions to be placed in the delay slot. We
2424   // do this before we actually schedule the current instruction,
2425   // because the delay slot follows the current instruction.
2426   if (Pipeline::_branch_has_delay_slot &&
2427       node_pipeline->hasBranchDelay() &&
2428       !_unconditional_delay_slot) {
2429 
2430     uint siz = _available.size();
2431 
2432     // Conditional branches can support an instruction that
2433     // is unconditionally executed and not dependent by the
2434     // branch, OR a conditionally executed instruction if
2435     // the branch is taken.  In practice, this means that
2436     // the first instruction at the branch target is
2437     // copied to the delay slot, and the branch goes to
2438     // the instruction after that at the branch target
2439     if ( n->is_MachBranch() ) {
2440 
2441       assert( !n->is_MachNullCheck(), "should not look for delay slot for Null Check" );
2442       assert( !n->is_Catch(),         "should not look for delay slot for Catch" );
2443 
2444 #ifndef PRODUCT
2445       _branches++;
2446 #endif
2447 
2448       // At least 1 instruction is on the available list
2449       // that is not dependent on the branch
2450       for (uint i = 0; i < siz; i++) {
2451         Node *d = _available[i];
2452         const Pipeline *avail_pipeline = d->pipeline();
2453 
2454         // Don't allow safepoints in the branch shadow, that will
2455         // cause a number of difficulties
2456         if ( avail_pipeline->instructionCount() == 1 &&
2457              !avail_pipeline->hasMultipleBundles() &&
2458              !avail_pipeline->hasBranchDelay() &&
2459              Pipeline::instr_has_unit_size() &&
2460              d->size(_regalloc) == Pipeline::instr_unit_size() &&
2461              NodeFitsInBundle(d) &&
2462              !node_bundling(d)->used_in_delay()) {
2463 
2464           if (d->is_Mach() && !d->is_MachSafePoint()) {
2465             // A node that fits in the delay slot was found, so we need to
2466             // set the appropriate bits in the bundle pipeline information so
2467             // that it correctly indicates resource usage.  Later, when we
2468             // attempt to add this instruction to the bundle, we will skip
2469             // setting the resource usage.
2470             _unconditional_delay_slot = d;
2471             node_bundling(n)->set_use_unconditional_delay();
2472             node_bundling(d)->set_used_in_unconditional_delay();
2473             _bundle_use.add_usage(avail_pipeline->resourceUse());
2474             _current_latency[d->_idx] = _bundle_cycle_number;
2475             _next_node = d;
2476             ++_bundle_instr_count;
2477 #ifndef PRODUCT
2478             _unconditional_delays++;
2479 #endif
2480             break;
2481           }
2482         }
2483       }
2484     }
2485 
2486     // No delay slot, add a nop to the usage
2487     if (!_unconditional_delay_slot) {
2488       // See if adding an instruction in the delay slot will overflow
2489       // the bundle.
2490       if (!NodeFitsInBundle(_nop)) {
2491 #ifndef PRODUCT
2492         if (_cfg->C->trace_opto_output())
2493           tty->print("#  *** STEP(1 instruction for delay slot) ***\n");
2494 #endif
2495         step(1);
2496       }
2497 
2498       _bundle_use.add_usage(_nop->pipeline()->resourceUse());
2499       _next_node = _nop;
2500       ++_bundle_instr_count;
2501     }
2502 
2503     // See if the instruction in the delay slot requires a
2504     // step of the bundles
2505     if (!NodeFitsInBundle(n)) {
2506 #ifndef PRODUCT
2507       if (_cfg->C->trace_opto_output())
2508         tty->print("#  *** STEP(branch won't fit) ***\n");
2509 #endif
2510       // Update the state information
2511       _bundle_instr_count = 0;
2512       _bundle_cycle_number += 1;
2513       _bundle_use.step(1);
2514     }
2515   }
2516 
2517   // Get the number of instructions
2518   uint instruction_count = node_pipeline->instructionCount();
2519   if (node_pipeline->mayHaveNoCode() && n->size(_regalloc) == 0)
2520     instruction_count = 0;
2521 
2522   // Compute the latency information
2523   uint delay = 0;
2524 
2525   if (instruction_count > 0 || !node_pipeline->mayHaveNoCode()) {
2526     int relative_latency = _current_latency[n->_idx] - _bundle_cycle_number;
2527     if (relative_latency < 0)
2528       relative_latency = 0;
2529 
2530     delay = _bundle_use.full_latency(relative_latency, node_usage);
2531 
2532     // Does not fit in this bundle, start a new one
2533     if (delay > 0) {
2534       step(delay);
2535 
2536 #ifndef PRODUCT
2537       if (_cfg->C->trace_opto_output())
2538         tty->print("#  *** STEP(%d) ***\n", delay);
2539 #endif
2540     }
2541   }
2542 
2543   // If this was placed in the delay slot, ignore it
2544   if (n != _unconditional_delay_slot) {
2545 
2546     if (delay == 0) {
2547       if (node_pipeline->hasMultipleBundles()) {
2548 #ifndef PRODUCT
2549         if (_cfg->C->trace_opto_output())
2550           tty->print("#  *** STEP(multiple instructions) ***\n");
2551 #endif
2552         step(1);
2553       }
2554 
2555       else if (instruction_count + _bundle_instr_count > Pipeline::_max_instrs_per_cycle) {
2556 #ifndef PRODUCT
2557         if (_cfg->C->trace_opto_output())
2558           tty->print("#  *** STEP(%d >= %d instructions) ***\n",
2559                      instruction_count + _bundle_instr_count,
2560                      Pipeline::_max_instrs_per_cycle);
2561 #endif
2562         step(1);
2563       }
2564     }
2565 
2566     if (node_pipeline->hasBranchDelay() && !_unconditional_delay_slot)
2567       _bundle_instr_count++;
2568 
2569     // Set the node's latency
2570     _current_latency[n->_idx] = _bundle_cycle_number;
2571 
2572     // Now merge the functional unit information
2573     if (instruction_count > 0 || !node_pipeline->mayHaveNoCode())
2574       _bundle_use.add_usage(node_usage);
2575 
2576     // Increment the number of instructions in this bundle
2577     _bundle_instr_count += instruction_count;
2578 
2579     // Remember this node for later
2580     if (n->is_Mach())
2581       _next_node = n;
2582   }
2583 
2584   // It's possible to have a BoxLock in the graph and in the _bbs mapping but
2585   // not in the bb->_nodes array.  This happens for debug-info-only BoxLocks.
2586   // 'Schedule' them (basically ignore in the schedule) but do not insert them
2587   // into the block.  All other scheduled nodes get put in the schedule here.
2588   int op = n->Opcode();
2589   if( (op == Op_Node && n->req() == 0) || // anti-dependence node OR
2590       (op != Op_Node &&         // Not an unused antidepedence node and
2591        // not an unallocated boxlock
2592        (OptoReg::is_valid(_regalloc->get_reg_first(n)) || op != Op_BoxLock)) ) {
2593 
2594     // Push any trailing projections
2595     if( bb->get_node(bb->number_of_nodes()-1) != n ) {
2596       for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2597         Node *foi = n->fast_out(i);
2598         if( foi->is_Proj() )
2599           _scheduled.push(foi);
2600       }
2601     }
2602 
2603     // Put the instruction in the schedule list
2604     _scheduled.push(n);
2605   }
2606 
2607 #ifndef PRODUCT
2608   if (_cfg->C->trace_opto_output())
2609     dump_available();
2610 #endif
2611 
2612   // Walk all the definitions, decrementing use counts, and
2613   // if a definition has a 0 use count, place it in the available list.
2614   DecrementUseCounts(n,bb);
2615 }
2616 
2617 // This method sets the use count within a basic block.  We will ignore all
2618 // uses outside the current basic block.  As we are doing a backwards walk,
2619 // any node we reach that has a use count of 0 may be scheduled.  This also
2620 // avoids the problem of cyclic references from phi nodes, as long as phi
2621 // nodes are at the front of the basic block.  This method also initializes
2622 // the available list to the set of instructions that have no uses within this
2623 // basic block.
2624 void Scheduling::ComputeUseCount(const Block *bb) {
2625 #ifndef PRODUCT
2626   if (_cfg->C->trace_opto_output())
2627     tty->print("# -> ComputeUseCount\n");
2628 #endif
2629 
2630   // Clear the list of available and scheduled instructions, just in case
2631   _available.clear();
2632   _scheduled.clear();
2633 
2634   // No delay slot specified
2635   _unconditional_delay_slot = nullptr;
2636 
2637 #ifdef ASSERT
2638   for( uint i=0; i < bb->number_of_nodes(); i++ )
2639     assert( _uses[bb->get_node(i)->_idx] == 0, "_use array not clean" );
2640 #endif
2641 
2642   // Force the _uses count to never go to zero for unscheduable pieces
2643   // of the block
2644   for( uint k = 0; k < _bb_start; k++ )
2645     _uses[bb->get_node(k)->_idx] = 1;
2646   for( uint l = _bb_end; l < bb->number_of_nodes(); l++ )
2647     _uses[bb->get_node(l)->_idx] = 1;
2648 
2649   // Iterate backwards over the instructions in the block.  Don't count the
2650   // branch projections at end or the block header instructions.
2651   for( uint j = _bb_end-1; j >= _bb_start; j-- ) {
2652     Node *n = bb->get_node(j);
2653     if( n->is_Proj() ) continue; // Projections handled another way
2654 
2655     // Account for all uses
2656     for ( uint k = 0; k < n->len(); k++ ) {
2657       Node *inp = n->in(k);
2658       if (!inp) continue;
2659       assert(inp != n, "no cycles allowed" );
2660       if (_cfg->get_block_for_node(inp) == bb) { // Block-local use?
2661         if (inp->is_Proj()) { // Skip through Proj's
2662           inp = inp->in(0);
2663         }
2664         ++_uses[inp->_idx];     // Count 1 block-local use
2665       }
2666     }
2667 
2668     // If this instruction has a 0 use count, then it is available
2669     if (!_uses[n->_idx]) {
2670       _current_latency[n->_idx] = _bundle_cycle_number;
2671       AddNodeToAvailableList(n);
2672     }
2673 
2674 #ifndef PRODUCT
2675     if (_cfg->C->trace_opto_output()) {
2676       tty->print("#   uses: %3d: ", _uses[n->_idx]);
2677       n->dump();
2678     }
2679 #endif
2680   }
2681 
2682 #ifndef PRODUCT
2683   if (_cfg->C->trace_opto_output())
2684     tty->print("# <- ComputeUseCount\n");
2685 #endif
2686 }
2687 
2688 // This routine performs scheduling on each basic block in reverse order,
2689 // using instruction latencies and taking into account function unit
2690 // availability.
2691 void Scheduling::DoScheduling() {
2692 #ifndef PRODUCT
2693   if (_cfg->C->trace_opto_output())
2694     tty->print("# -> DoScheduling\n");
2695 #endif
2696 
2697   Block *succ_bb = nullptr;
2698   Block *bb;
2699   Compile* C = Compile::current();
2700 
2701   // Walk over all the basic blocks in reverse order
2702   for (int i = _cfg->number_of_blocks() - 1; i >= 0; succ_bb = bb, i--) {
2703     bb = _cfg->get_block(i);
2704 
2705 #ifndef PRODUCT
2706     if (_cfg->C->trace_opto_output()) {
2707       tty->print("#  Schedule BB#%03d (initial)\n", i);
2708       for (uint j = 0; j < bb->number_of_nodes(); j++) {
2709         bb->get_node(j)->dump();
2710       }
2711     }
2712 #endif
2713 
2714     // On the head node, skip processing
2715     if (bb == _cfg->get_root_block()) {
2716       continue;
2717     }
2718 
2719     // Skip empty, connector blocks
2720     if (bb->is_connector())
2721       continue;
2722 
2723     // If the following block is not the sole successor of
2724     // this one, then reset the pipeline information
2725     if (bb->_num_succs != 1 || bb->non_connector_successor(0) != succ_bb) {
2726 #ifndef PRODUCT
2727       if (_cfg->C->trace_opto_output()) {
2728         tty->print("*** bundle start of next BB, node %d, for %d instructions\n",
2729                    _next_node->_idx, _bundle_instr_count);
2730       }
2731 #endif
2732       step_and_clear();
2733     }
2734 
2735     // Leave untouched the starting instruction, any Phis, a CreateEx node
2736     // or Top.  bb->get_node(_bb_start) is the first schedulable instruction.
2737     _bb_end = bb->number_of_nodes()-1;
2738     for( _bb_start=1; _bb_start <= _bb_end; _bb_start++ ) {
2739       Node *n = bb->get_node(_bb_start);
2740       // Things not matched, like Phinodes and ProjNodes don't get scheduled.
2741       // Also, MachIdealNodes do not get scheduled
2742       if( !n->is_Mach() ) continue;     // Skip non-machine nodes
2743       MachNode *mach = n->as_Mach();
2744       int iop = mach->ideal_Opcode();
2745       if( iop == Op_CreateEx ) continue; // CreateEx is pinned
2746       if( iop == Op_Con ) continue;      // Do not schedule Top
2747       if( iop == Op_Node &&     // Do not schedule PhiNodes, ProjNodes
2748           mach->pipeline() == MachNode::pipeline_class() &&
2749           !n->is_SpillCopy() && !n->is_MachMerge() )  // Breakpoints, Prolog, etc
2750         continue;
2751       break;                    // Funny loop structure to be sure...
2752     }
2753     // Compute last "interesting" instruction in block - last instruction we
2754     // might schedule.  _bb_end points just after last schedulable inst.  We
2755     // normally schedule conditional branches (despite them being forced last
2756     // in the block), because they have delay slots we can fill.  Calls all
2757     // have their delay slots filled in the template expansions, so we don't
2758     // bother scheduling them.
2759     Node *last = bb->get_node(_bb_end);
2760     // Ignore trailing NOPs.
2761     while (_bb_end > 0 && last->is_Mach() &&
2762            last->as_Mach()->ideal_Opcode() == Op_Con) {
2763       last = bb->get_node(--_bb_end);
2764     }
2765     assert(!last->is_Mach() || last->as_Mach()->ideal_Opcode() != Op_Con, "");
2766     if( last->is_Catch() ||
2767         (last->is_Mach() && last->as_Mach()->ideal_Opcode() == Op_Halt) ) {
2768       // There might be a prior call.  Skip it.
2769       while (_bb_start < _bb_end && bb->get_node(--_bb_end)->is_MachProj());
2770     } else if( last->is_MachNullCheck() ) {
2771       // Backup so the last null-checked memory instruction is
2772       // outside the schedulable range. Skip over the nullcheck,
2773       // projection, and the memory nodes.
2774       Node *mem = last->in(1);
2775       do {
2776         _bb_end--;
2777       } while (mem != bb->get_node(_bb_end));
2778     } else {
2779       // Set _bb_end to point after last schedulable inst.
2780       _bb_end++;
2781     }
2782 
2783     assert( _bb_start <= _bb_end, "inverted block ends" );
2784 
2785     // Compute the register antidependencies for the basic block
2786     ComputeRegisterAntidependencies(bb);
2787     if (C->failing())  return;  // too many D-U pinch points
2788 
2789     // Compute the usage within the block, and set the list of all nodes
2790     // in the block that have no uses within the block.
2791     ComputeUseCount(bb);
2792 
2793     // Schedule the remaining instructions in the block
2794     while ( _available.size() > 0 ) {
2795       Node *n = ChooseNodeToBundle();
2796       guarantee(n != nullptr, "no nodes available");
2797       AddNodeToBundle(n,bb);
2798     }
2799 
2800     assert( _scheduled.size() == _bb_end - _bb_start, "wrong number of instructions" );
2801 #ifdef ASSERT
2802     for( uint l = _bb_start; l < _bb_end; l++ ) {
2803       Node *n = bb->get_node(l);
2804       uint m;
2805       for( m = 0; m < _bb_end-_bb_start; m++ )
2806         if( _scheduled[m] == n )
2807           break;
2808       assert( m < _bb_end-_bb_start, "instruction missing in schedule" );
2809     }
2810 #endif
2811 
2812     // Now copy the instructions (in reverse order) back to the block
2813     for ( uint k = _bb_start; k < _bb_end; k++ )
2814       bb->map_node(_scheduled[_bb_end-k-1], k);
2815 
2816 #ifndef PRODUCT
2817     if (_cfg->C->trace_opto_output()) {
2818       tty->print("#  Schedule BB#%03d (final)\n", i);
2819       uint current = 0;
2820       for (uint j = 0; j < bb->number_of_nodes(); j++) {
2821         Node *n = bb->get_node(j);
2822         if( valid_bundle_info(n) ) {
2823           Bundle *bundle = node_bundling(n);
2824           if (bundle->instr_count() > 0 || bundle->flags() > 0) {
2825             tty->print("*** Bundle: ");
2826             bundle->dump();
2827           }
2828           n->dump();
2829         }
2830       }
2831     }
2832 #endif
2833 #ifdef ASSERT
2834     verify_good_schedule(bb,"after block local scheduling");
2835 #endif
2836   }
2837 
2838 #ifndef PRODUCT
2839   if (_cfg->C->trace_opto_output())
2840     tty->print("# <- DoScheduling\n");
2841 #endif
2842 
2843   // Record final node-bundling array location
2844   _regalloc->C->output()->set_node_bundling_base(_node_bundling_base);
2845 
2846 } // end DoScheduling
2847 
2848 // Verify that no live-range used in the block is killed in the block by a
2849 // wrong DEF.  This doesn't verify live-ranges that span blocks.
2850 
2851 // Check for edge existence.  Used to avoid adding redundant precedence edges.
2852 static bool edge_from_to( Node *from, Node *to ) {
2853   for( uint i=0; i<from->len(); i++ )
2854     if( from->in(i) == to )
2855       return true;
2856   return false;
2857 }
2858 
2859 #ifdef ASSERT
2860 void Scheduling::verify_do_def( Node *n, OptoReg::Name def, const char *msg ) {
2861   // Check for bad kills
2862   if( OptoReg::is_valid(def) ) { // Ignore stores & control flow
2863     Node *prior_use = _reg_node[def];
2864     if( prior_use && !edge_from_to(prior_use,n) ) {
2865       tty->print("%s = ",OptoReg::as_VMReg(def)->name());
2866       n->dump();
2867       tty->print_cr("...");
2868       prior_use->dump();
2869       assert(edge_from_to(prior_use,n), "%s", msg);
2870     }
2871     _reg_node.map(def,nullptr); // Kill live USEs
2872   }
2873 }
2874 
2875 void Scheduling::verify_good_schedule( Block *b, const char *msg ) {
2876 
2877   // Zap to something reasonable for the verify code
2878   _reg_node.clear();
2879 
2880   // Walk over the block backwards.  Check to make sure each DEF doesn't
2881   // kill a live value (other than the one it's supposed to).  Add each
2882   // USE to the live set.
2883   for( uint i = b->number_of_nodes()-1; i >= _bb_start; i-- ) {
2884     Node *n = b->get_node(i);
2885     int n_op = n->Opcode();
2886     if( n_op == Op_MachProj && n->ideal_reg() == MachProjNode::fat_proj ) {
2887       // Fat-proj kills a slew of registers
2888       RegMaskIterator rmi(n->out_RegMask());
2889       while (rmi.has_next()) {
2890         OptoReg::Name kill = rmi.next();
2891         verify_do_def(n, kill, msg);
2892       }
2893     } else if( n_op != Op_Node ) { // Avoid brand new antidependence nodes
2894       // Get DEF'd registers the normal way
2895       verify_do_def( n, _regalloc->get_reg_first(n), msg );
2896       verify_do_def( n, _regalloc->get_reg_second(n), msg );
2897     }
2898 
2899     // Now make all USEs live
2900     for( uint i=1; i<n->req(); i++ ) {
2901       Node *def = n->in(i);
2902       assert(def != 0, "input edge required");
2903       OptoReg::Name reg_lo = _regalloc->get_reg_first(def);
2904       OptoReg::Name reg_hi = _regalloc->get_reg_second(def);
2905       if( OptoReg::is_valid(reg_lo) ) {
2906         assert(!_reg_node[reg_lo] || edge_from_to(_reg_node[reg_lo],def), "%s", msg);
2907         _reg_node.map(reg_lo,n);
2908       }
2909       if( OptoReg::is_valid(reg_hi) ) {
2910         assert(!_reg_node[reg_hi] || edge_from_to(_reg_node[reg_hi],def), "%s", msg);
2911         _reg_node.map(reg_hi,n);
2912       }
2913     }
2914 
2915   }
2916 
2917   // Zap to something reasonable for the Antidependence code
2918   _reg_node.clear();
2919 }
2920 #endif
2921 
2922 // Conditionally add precedence edges.  Avoid putting edges on Projs.
2923 static void add_prec_edge_from_to( Node *from, Node *to ) {
2924   if( from->is_Proj() ) {       // Put precedence edge on Proj's input
2925     assert( from->req() == 1 && (from->len() == 1 || from->in(1)==0), "no precedence edges on projections" );
2926     from = from->in(0);
2927   }
2928   if( from != to &&             // No cycles (for things like LD L0,[L0+4] )
2929       !edge_from_to( from, to ) ) // Avoid duplicate edge
2930     from->add_prec(to);
2931 }
2932 
2933 void Scheduling::anti_do_def( Block *b, Node *def, OptoReg::Name def_reg, int is_def ) {
2934   if( !OptoReg::is_valid(def_reg) ) // Ignore stores & control flow
2935     return;
2936 
2937   if (OptoReg::is_reg(def_reg)) {
2938     VMReg vmreg = OptoReg::as_VMReg(def_reg);
2939     if (vmreg->is_reg() && !vmreg->is_concrete() && !vmreg->prev()->is_concrete()) {
2940       // This is one of the high slots of a vector register.
2941       // ScheduleAndBundle already checked there are no live wide
2942       // vectors in this method so it can be safely ignored.
2943       return;
2944     }
2945   }
2946 
2947   Node *pinch = _reg_node[def_reg]; // Get pinch point
2948   if ((pinch == nullptr) || _cfg->get_block_for_node(pinch) != b || // No pinch-point yet?
2949       is_def ) {    // Check for a true def (not a kill)
2950     _reg_node.map(def_reg,def); // Record def/kill as the optimistic pinch-point
2951     return;
2952   }
2953 
2954   Node *kill = def;             // Rename 'def' to more descriptive 'kill'
2955   debug_only( def = (Node*)((intptr_t)0xdeadbeef); )
2956 
2957   // After some number of kills there _may_ be a later def
2958   Node *later_def = nullptr;
2959 
2960   Compile* C = Compile::current();
2961 
2962   // Finding a kill requires a real pinch-point.
2963   // Check for not already having a pinch-point.
2964   // Pinch points are Op_Node's.
2965   if( pinch->Opcode() != Op_Node ) { // Or later-def/kill as pinch-point?
2966     later_def = pinch;            // Must be def/kill as optimistic pinch-point
2967     if ( _pinch_free_list.size() > 0) {
2968       pinch = _pinch_free_list.pop();
2969     } else {
2970       pinch = new Node(1); // Pinch point to-be
2971     }
2972     if (pinch->_idx >= _regalloc->node_regs_max_index()) {
2973       DEBUG_ONLY( pinch->dump(); );
2974       assert(false, "too many D-U pinch points: %d >= %d", pinch->_idx, _regalloc->node_regs_max_index());
2975       _cfg->C->record_method_not_compilable("too many D-U pinch points");
2976       return;
2977     }
2978     _cfg->map_node_to_block(pinch, b);      // Pretend it's valid in this block (lazy init)
2979     _reg_node.map(def_reg,pinch); // Record pinch-point
2980     //regalloc()->set_bad(pinch->_idx); // Already initialized this way.
2981     if( later_def->outcnt() == 0 || later_def->ideal_reg() == MachProjNode::fat_proj ) { // Distinguish def from kill
2982       pinch->init_req(0, C->top());     // set not null for the next call
2983       add_prec_edge_from_to(later_def,pinch); // Add edge from kill to pinch
2984       later_def = nullptr;           // and no later def
2985     }
2986     pinch->set_req(0,later_def);  // Hook later def so we can find it
2987   } else {                        // Else have valid pinch point
2988     if( pinch->in(0) )            // If there is a later-def
2989       later_def = pinch->in(0);   // Get it
2990   }
2991 
2992   // Add output-dependence edge from later def to kill
2993   if( later_def )               // If there is some original def
2994     add_prec_edge_from_to(later_def,kill); // Add edge from def to kill
2995 
2996   // See if current kill is also a use, and so is forced to be the pinch-point.
2997   if( pinch->Opcode() == Op_Node ) {
2998     Node *uses = kill->is_Proj() ? kill->in(0) : kill;
2999     for( uint i=1; i<uses->req(); i++ ) {
3000       if( _regalloc->get_reg_first(uses->in(i)) == def_reg ||
3001           _regalloc->get_reg_second(uses->in(i)) == def_reg ) {
3002         // Yes, found a use/kill pinch-point
3003         pinch->set_req(0,nullptr);  //
3004         pinch->replace_by(kill); // Move anti-dep edges up
3005         pinch = kill;
3006         _reg_node.map(def_reg,pinch);
3007         return;
3008       }
3009     }
3010   }
3011 
3012   // Add edge from kill to pinch-point
3013   add_prec_edge_from_to(kill,pinch);
3014 }
3015 
3016 void Scheduling::anti_do_use( Block *b, Node *use, OptoReg::Name use_reg ) {
3017   if( !OptoReg::is_valid(use_reg) ) // Ignore stores & control flow
3018     return;
3019   Node *pinch = _reg_node[use_reg]; // Get pinch point
3020   // Check for no later def_reg/kill in block
3021   if ((pinch != nullptr) && _cfg->get_block_for_node(pinch) == b &&
3022       // Use has to be block-local as well
3023       _cfg->get_block_for_node(use) == b) {
3024     if( pinch->Opcode() == Op_Node && // Real pinch-point (not optimistic?)
3025         pinch->req() == 1 ) {   // pinch not yet in block?
3026       pinch->del_req(0);        // yank pointer to later-def, also set flag
3027       // Insert the pinch-point in the block just after the last use
3028       b->insert_node(pinch, b->find_node(use) + 1);
3029       _bb_end++;                // Increase size scheduled region in block
3030     }
3031 
3032     add_prec_edge_from_to(pinch,use);
3033   }
3034 }
3035 
3036 // We insert antidependences between the reads and following write of
3037 // allocated registers to prevent illegal code motion. Hopefully, the
3038 // number of added references should be fairly small, especially as we
3039 // are only adding references within the current basic block.
3040 void Scheduling::ComputeRegisterAntidependencies(Block *b) {
3041 
3042 #ifdef ASSERT
3043   verify_good_schedule(b,"before block local scheduling");
3044 #endif
3045 
3046   // A valid schedule, for each register independently, is an endless cycle
3047   // of: a def, then some uses (connected to the def by true dependencies),
3048   // then some kills (defs with no uses), finally the cycle repeats with a new
3049   // def.  The uses are allowed to float relative to each other, as are the
3050   // kills.  No use is allowed to slide past a kill (or def).  This requires
3051   // antidependencies between all uses of a single def and all kills that
3052   // follow, up to the next def.  More edges are redundant, because later defs
3053   // & kills are already serialized with true or antidependencies.  To keep
3054   // the edge count down, we add a 'pinch point' node if there's more than
3055   // one use or more than one kill/def.
3056 
3057   // We add dependencies in one bottom-up pass.
3058 
3059   // For each instruction we handle it's DEFs/KILLs, then it's USEs.
3060 
3061   // For each DEF/KILL, we check to see if there's a prior DEF/KILL for this
3062   // register.  If not, we record the DEF/KILL in _reg_node, the
3063   // register-to-def mapping.  If there is a prior DEF/KILL, we insert a
3064   // "pinch point", a new Node that's in the graph but not in the block.
3065   // We put edges from the prior and current DEF/KILLs to the pinch point.
3066   // We put the pinch point in _reg_node.  If there's already a pinch point
3067   // we merely add an edge from the current DEF/KILL to the pinch point.
3068 
3069   // After doing the DEF/KILLs, we handle USEs.  For each used register, we
3070   // put an edge from the pinch point to the USE.
3071 
3072   // To be expedient, the _reg_node array is pre-allocated for the whole
3073   // compilation.  _reg_node is lazily initialized; it either contains a null,
3074   // or a valid def/kill/pinch-point, or a leftover node from some prior
3075   // block.  Leftover node from some prior block is treated like a null (no
3076   // prior def, so no anti-dependence needed).  Valid def is distinguished by
3077   // it being in the current block.
3078   bool fat_proj_seen = false;
3079   uint last_safept = _bb_end-1;
3080   Node* end_node         = (_bb_end-1 >= _bb_start) ? b->get_node(last_safept) : nullptr;
3081   Node* last_safept_node = end_node;
3082   for( uint i = _bb_end-1; i >= _bb_start; i-- ) {
3083     Node *n = b->get_node(i);
3084     int is_def = n->outcnt();   // def if some uses prior to adding precedence edges
3085     if( n->is_MachProj() && n->ideal_reg() == MachProjNode::fat_proj ) {
3086       // Fat-proj kills a slew of registers
3087       // This can add edges to 'n' and obscure whether or not it was a def,
3088       // hence the is_def flag.
3089       fat_proj_seen = true;
3090       RegMaskIterator rmi(n->out_RegMask());
3091       while (rmi.has_next()) {
3092         OptoReg::Name kill = rmi.next();
3093         anti_do_def(b, n, kill, is_def);
3094       }
3095     } else {
3096       // Get DEF'd registers the normal way
3097       anti_do_def( b, n, _regalloc->get_reg_first(n), is_def );
3098       anti_do_def( b, n, _regalloc->get_reg_second(n), is_def );
3099     }
3100 
3101     // Kill projections on a branch should appear to occur on the
3102     // branch, not afterwards, so grab the masks from the projections
3103     // and process them.
3104     if (n->is_MachBranch() || (n->is_Mach() && n->as_Mach()->ideal_Opcode() == Op_Jump)) {
3105       for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
3106         Node* use = n->fast_out(i);
3107         if (use->is_Proj()) {
3108           RegMaskIterator rmi(use->out_RegMask());
3109           while (rmi.has_next()) {
3110             OptoReg::Name kill = rmi.next();
3111             anti_do_def(b, n, kill, false);
3112           }
3113         }
3114       }
3115     }
3116 
3117     // Check each register used by this instruction for a following DEF/KILL
3118     // that must occur afterward and requires an anti-dependence edge.
3119     for( uint j=0; j<n->req(); j++ ) {
3120       Node *def = n->in(j);
3121       if( def ) {
3122         assert( !def->is_MachProj() || def->ideal_reg() != MachProjNode::fat_proj, "" );
3123         anti_do_use( b, n, _regalloc->get_reg_first(def) );
3124         anti_do_use( b, n, _regalloc->get_reg_second(def) );
3125       }
3126     }
3127     // Do not allow defs of new derived values to float above GC
3128     // points unless the base is definitely available at the GC point.
3129 
3130     Node *m = b->get_node(i);
3131 
3132     // Add precedence edge from following safepoint to use of derived pointer
3133     if( last_safept_node != end_node &&
3134         m != last_safept_node) {
3135       for (uint k = 1; k < m->req(); k++) {
3136         const Type *t = m->in(k)->bottom_type();
3137         if( t->isa_oop_ptr() &&
3138             t->is_ptr()->offset() != 0 ) {
3139           last_safept_node->add_prec( m );
3140           break;
3141         }
3142       }
3143     }
3144 
3145     if( n->jvms() ) {           // Precedence edge from derived to safept
3146       // Check if last_safept_node was moved by pinch-point insertion in anti_do_use()
3147       if( b->get_node(last_safept) != last_safept_node ) {
3148         last_safept = b->find_node(last_safept_node);
3149       }
3150       for( uint j=last_safept; j > i; j-- ) {
3151         Node *mach = b->get_node(j);
3152         if( mach->is_Mach() && mach->as_Mach()->ideal_Opcode() == Op_AddP )
3153           mach->add_prec( n );
3154       }
3155       last_safept = i;
3156       last_safept_node = m;
3157     }
3158   }
3159 
3160   if (fat_proj_seen) {
3161     // Garbage collect pinch nodes that were not consumed.
3162     // They are usually created by a fat kill MachProj for a call.
3163     garbage_collect_pinch_nodes();
3164   }
3165 }
3166 
3167 // Garbage collect pinch nodes for reuse by other blocks.
3168 //
3169 // The block scheduler's insertion of anti-dependence
3170 // edges creates many pinch nodes when the block contains
3171 // 2 or more Calls.  A pinch node is used to prevent a
3172 // combinatorial explosion of edges.  If a set of kills for a
3173 // register is anti-dependent on a set of uses (or defs), rather
3174 // than adding an edge in the graph between each pair of kill
3175 // and use (or def), a pinch is inserted between them:
3176 //
3177 //            use1   use2  use3
3178 //                \   |   /
3179 //                 \  |  /
3180 //                  pinch
3181 //                 /  |  \
3182 //                /   |   \
3183 //            kill1 kill2 kill3
3184 //
3185 // One pinch node is created per register killed when
3186 // the second call is encountered during a backwards pass
3187 // over the block.  Most of these pinch nodes are never
3188 // wired into the graph because the register is never
3189 // used or def'ed in the block.
3190 //
3191 void Scheduling::garbage_collect_pinch_nodes() {
3192 #ifndef PRODUCT
3193   if (_cfg->C->trace_opto_output()) tty->print("Reclaimed pinch nodes:");
3194 #endif
3195   int trace_cnt = 0;
3196   for (uint k = 0; k < _reg_node.max(); k++) {
3197     Node* pinch = _reg_node[k];
3198     if ((pinch != nullptr) && pinch->Opcode() == Op_Node &&
3199         // no predecence input edges
3200         (pinch->req() == pinch->len() || pinch->in(pinch->req()) == nullptr) ) {
3201       cleanup_pinch(pinch);
3202       _pinch_free_list.push(pinch);
3203       _reg_node.map(k, nullptr);
3204 #ifndef PRODUCT
3205       if (_cfg->C->trace_opto_output()) {
3206         trace_cnt++;
3207         if (trace_cnt > 40) {
3208           tty->print("\n");
3209           trace_cnt = 0;
3210         }
3211         tty->print(" %d", pinch->_idx);
3212       }
3213 #endif
3214     }
3215   }
3216 #ifndef PRODUCT
3217   if (_cfg->C->trace_opto_output()) tty->print("\n");
3218 #endif
3219 }
3220 
3221 // Clean up a pinch node for reuse.
3222 void Scheduling::cleanup_pinch( Node *pinch ) {
3223   assert (pinch && pinch->Opcode() == Op_Node && pinch->req() == 1, "just checking");
3224 
3225   for (DUIterator_Last imin, i = pinch->last_outs(imin); i >= imin; ) {
3226     Node* use = pinch->last_out(i);
3227     uint uses_found = 0;
3228     for (uint j = use->req(); j < use->len(); j++) {
3229       if (use->in(j) == pinch) {
3230         use->rm_prec(j);
3231         uses_found++;
3232       }
3233     }
3234     assert(uses_found > 0, "must be a precedence edge");
3235     i -= uses_found;    // we deleted 1 or more copies of this edge
3236   }
3237   // May have a later_def entry
3238   pinch->set_req(0, nullptr);
3239 }
3240 
3241 #ifndef PRODUCT
3242 
3243 void Scheduling::dump_available() const {
3244   tty->print("#Availist  ");
3245   for (uint i = 0; i < _available.size(); i++)
3246     tty->print(" N%d/l%d", _available[i]->_idx,_current_latency[_available[i]->_idx]);
3247   tty->cr();
3248 }
3249 
3250 // Print Scheduling Statistics
3251 void Scheduling::print_statistics() {
3252   // Print the size added by nops for bundling
3253   tty->print("Nops added %d bytes to total of %d bytes",
3254              _total_nop_size, _total_method_size);
3255   if (_total_method_size > 0)
3256     tty->print(", for %.2f%%",
3257                ((double)_total_nop_size) / ((double) _total_method_size) * 100.0);
3258   tty->print("\n");
3259 
3260   // Print the number of branch shadows filled
3261   if (Pipeline::_branch_has_delay_slot) {
3262     tty->print("Of %d branches, %d had unconditional delay slots filled",
3263                _total_branches, _total_unconditional_delays);
3264     if (_total_branches > 0)
3265       tty->print(", for %.2f%%",
3266                  ((double)_total_unconditional_delays) / ((double)_total_branches) * 100.0);
3267     tty->print("\n");
3268   }
3269 
3270   uint total_instructions = 0, total_bundles = 0;
3271 
3272   for (uint i = 1; i <= Pipeline::_max_instrs_per_cycle; i++) {
3273     uint bundle_count   = _total_instructions_per_bundle[i];
3274     total_instructions += bundle_count * i;
3275     total_bundles      += bundle_count;
3276   }
3277 
3278   if (total_bundles > 0)
3279     tty->print("Average ILP (excluding nops) is %.2f\n",
3280                ((double)total_instructions) / ((double)total_bundles));
3281 }
3282 #endif
3283 
3284 //-----------------------init_scratch_buffer_blob------------------------------
3285 // Construct a temporary BufferBlob and cache it for this compile.
3286 void PhaseOutput::init_scratch_buffer_blob(int const_size) {
3287   // If there is already a scratch buffer blob allocated and the
3288   // constant section is big enough, use it.  Otherwise free the
3289   // current and allocate a new one.
3290   BufferBlob* blob = scratch_buffer_blob();
3291   if ((blob != nullptr) && (const_size <= _scratch_const_size)) {
3292     // Use the current blob.
3293   } else {
3294     if (blob != nullptr) {
3295       BufferBlob::free(blob);
3296     }
3297 
3298     ResourceMark rm;
3299     _scratch_const_size = const_size;
3300     int size = C2Compiler::initial_code_buffer_size(const_size);
3301     blob = BufferBlob::create("Compile::scratch_buffer", size);
3302     // Record the buffer blob for next time.
3303     set_scratch_buffer_blob(blob);
3304     // Have we run out of code space?
3305     if (scratch_buffer_blob() == nullptr) {
3306       // Let CompilerBroker disable further compilations.
3307       C->record_failure("Not enough space for scratch buffer in CodeCache");
3308       return;
3309     }
3310   }
3311 
3312   // Initialize the relocation buffers
3313   relocInfo* locs_buf = (relocInfo*) blob->content_end() - MAX_locs_size;
3314   set_scratch_locs_memory(locs_buf);
3315 }
3316 
3317 
3318 //-----------------------scratch_emit_size-------------------------------------
3319 // Helper function that computes size by emitting code
3320 uint PhaseOutput::scratch_emit_size(const Node* n) {
3321   // Start scratch_emit_size section.
3322   set_in_scratch_emit_size(true);
3323 
3324   // Emit into a trash buffer and count bytes emitted.
3325   // This is a pretty expensive way to compute a size,
3326   // but it works well enough if seldom used.
3327   // All common fixed-size instructions are given a size
3328   // method by the AD file.
3329   // Note that the scratch buffer blob and locs memory are
3330   // allocated at the beginning of the compile task, and
3331   // may be shared by several calls to scratch_emit_size.
3332   // The allocation of the scratch buffer blob is particularly
3333   // expensive, since it has to grab the code cache lock.
3334   BufferBlob* blob = this->scratch_buffer_blob();
3335   assert(blob != nullptr, "Initialize BufferBlob at start");
3336   assert(blob->size() > MAX_inst_size, "sanity");
3337   relocInfo* locs_buf = scratch_locs_memory();
3338   address blob_begin = blob->content_begin();
3339   address blob_end   = (address)locs_buf;
3340   assert(blob->contains(blob_end), "sanity");
3341   CodeBuffer buf(blob_begin, blob_end - blob_begin);
3342   buf.initialize_consts_size(_scratch_const_size);
3343   buf.initialize_stubs_size(MAX_stubs_size);
3344   assert(locs_buf != nullptr, "sanity");
3345   int lsize = MAX_locs_size / 3;
3346   buf.consts()->initialize_shared_locs(&locs_buf[lsize * 0], lsize);
3347   buf.insts()->initialize_shared_locs( &locs_buf[lsize * 1], lsize);
3348   buf.stubs()->initialize_shared_locs( &locs_buf[lsize * 2], lsize);
3349   // Mark as scratch buffer.
3350   buf.consts()->set_scratch_emit();
3351   buf.insts()->set_scratch_emit();
3352   buf.stubs()->set_scratch_emit();
3353 
3354   // Do the emission.
3355 
3356   Label fakeL; // Fake label for branch instructions.
3357   Label*   saveL = nullptr;
3358   uint save_bnum = 0;
3359   bool is_branch = n->is_MachBranch();
3360   if (is_branch) {
3361     MacroAssembler masm(&buf);
3362     masm.bind(fakeL);
3363     n->as_MachBranch()->save_label(&saveL, &save_bnum);
3364     n->as_MachBranch()->label_set(&fakeL, 0);
3365   }
3366   n->emit(buf, C->regalloc());
3367 
3368   // Emitting into the scratch buffer should not fail
3369   assert (!C->failing(), "Must not have pending failure. Reason is: %s", C->failure_reason());
3370 
3371   if (is_branch) // Restore label.
3372     n->as_MachBranch()->label_set(saveL, save_bnum);
3373 
3374   // End scratch_emit_size section.
3375   set_in_scratch_emit_size(false);
3376 
3377   return buf.insts_size();
3378 }
3379 
3380 void PhaseOutput::install() {
3381   if (C->should_install_code() && C->stub_function() != nullptr) {
3382     install_stub(C->stub_name());
3383   } else {
3384     install_code(C->method(),
3385                  C->entry_bci(),
3386                  CompilerThread::current()->compiler(),
3387                  C->has_unsafe_access(),
3388                  SharedRuntime::is_wide_vector(C->max_vector_size()),
3389                  C->rtm_state());
3390   }
3391 }
3392 
3393 void PhaseOutput::install_code(ciMethod*         target,
3394                                int               entry_bci,
3395                                AbstractCompiler* compiler,
3396                                bool              has_unsafe_access,
3397                                bool              has_wide_vectors,
3398                                RTMState          rtm_state) {
3399   // Check if we want to skip execution of all compiled code.
3400   {
3401 #ifndef PRODUCT
3402     if (OptoNoExecute) {
3403       C->record_method_not_compilable("+OptoNoExecute");  // Flag as failed
3404       return;
3405     }
3406 #endif
3407     Compile::TracePhase tp("install_code", &timers[_t_registerMethod]);
3408 
3409     if (C->is_osr_compilation()) {
3410       _code_offsets.set_value(CodeOffsets::Verified_Entry, 0);
3411       _code_offsets.set_value(CodeOffsets::OSR_Entry, _first_block_size);
3412     } else {
3413       if (!target->is_static()) {
3414         // The UEP of an nmethod ensures that the VEP is padded. However, the padding of the UEP is placed
3415         // before the inline cache check, so we don't have to execute any nop instructions when dispatching
3416         // through the UEP, yet we can ensure that the VEP is aligned appropriately.
3417         _code_offsets.set_value(CodeOffsets::Entry, _first_block_size - MacroAssembler::ic_check_size());
3418       }
3419       _code_offsets.set_value(CodeOffsets::Verified_Entry, _first_block_size);
3420       _code_offsets.set_value(CodeOffsets::OSR_Entry, 0);
3421     }
3422 
3423     C->env()->register_method(target,
3424                                      entry_bci,
3425                                      &_code_offsets,
3426                                      _orig_pc_slot_offset_in_bytes,
3427                                      code_buffer(),
3428                                      frame_size_in_words(),
3429                                      oop_map_set(),
3430                                      &_handler_table,
3431                                      inc_table(),
3432                                      compiler,
3433                                      C->has_clinit_barriers(),
3434                                      C->for_preload(),
3435                                      has_unsafe_access,
3436                                      SharedRuntime::is_wide_vector(C->max_vector_size()),
3437                                      C->has_monitors(),
3438                                      0,
3439                                      C->should_install_code(),
3440                                      C->rtm_state());
3441 
3442     if (C->log() != nullptr) { // Print code cache state into compiler log
3443       C->log()->code_cache_state();
3444     }
3445     if (C->has_clinit_barriers()) {
3446       assert(C->for_preload(), "sanity");
3447       // Build second version of code without class initialization barriers
3448       if (C->env()->task()->compile_reason() == CompileTask::Reason_PrecompileForPreload) {
3449         // don't automatically precompile a barrier-free version unless explicitly asked
3450       } else {
3451         C->record_failure(C2Compiler::retry_no_clinit_barriers());
3452       }
3453     }
3454   }
3455 }
3456 void PhaseOutput::install_stub(const char* stub_name) {
3457   // Entry point will be accessed using stub_entry_point();
3458   if (code_buffer() == nullptr) {
3459     Matcher::soft_match_failure();
3460   } else {
3461     if (PrintAssembly && (WizardMode || Verbose))
3462       tty->print_cr("### Stub::%s", stub_name);
3463 
3464     if (!C->failing()) {
3465       assert(C->fixed_slots() == 0, "no fixed slots used for runtime stubs");
3466 
3467       // Make the NMethod
3468       // For now we mark the frame as never safe for profile stackwalking
3469       RuntimeStub *rs = RuntimeStub::new_runtime_stub(stub_name,
3470                                                       code_buffer(),
3471                                                       CodeOffsets::frame_never_safe,
3472                                                       // _code_offsets.value(CodeOffsets::Frame_Complete),
3473                                                       frame_size_in_words(),
3474                                                       oop_map_set(),
3475                                                       false);
3476       assert(rs != nullptr && rs->is_runtime_stub(), "sanity check");
3477 
3478       C->set_stub_entry_point(rs->entry_point());
3479     }
3480   }
3481 }
3482 
3483 // Support for bundling info
3484 Bundle* PhaseOutput::node_bundling(const Node *n) {
3485   assert(valid_bundle_info(n), "oob");
3486   return &_node_bundling_base[n->_idx];
3487 }
3488 
3489 bool PhaseOutput::valid_bundle_info(const Node *n) {
3490   return (_node_bundling_limit > n->_idx);
3491 }
3492 
3493 //------------------------------frame_size_in_words-----------------------------
3494 // frame_slots in units of words
3495 int PhaseOutput::frame_size_in_words() const {
3496   // shift is 0 in LP32 and 1 in LP64
3497   const int shift = (LogBytesPerWord - LogBytesPerInt);
3498   int words = _frame_slots >> shift;
3499   assert( words << shift == _frame_slots, "frame size must be properly aligned in LP64" );
3500   return words;
3501 }
3502 
3503 // To bang the stack of this compiled method we use the stack size
3504 // that the interpreter would need in case of a deoptimization. This
3505 // removes the need to bang the stack in the deoptimization blob which
3506 // in turn simplifies stack overflow handling.
3507 int PhaseOutput::bang_size_in_bytes() const {
3508   return MAX2(frame_size_in_bytes() + os::extra_bang_size_in_bytes(), C->interpreter_frame_size());
3509 }
3510 
3511 //------------------------------dump_asm---------------------------------------
3512 // Dump formatted assembly
3513 #if defined(SUPPORT_OPTO_ASSEMBLY)
3514 void PhaseOutput::dump_asm_on(outputStream* st, int* pcs, uint pc_limit) {
3515 
3516   int pc_digits = 3; // #chars required for pc
3517   int sb_chars  = 3; // #chars for "start bundle" indicator
3518   int tab_size  = 8;
3519   if (pcs != nullptr) {
3520     int max_pc = 0;
3521     for (uint i = 0; i < pc_limit; i++) {
3522       max_pc = (max_pc < pcs[i]) ? pcs[i] : max_pc;
3523     }
3524     pc_digits  = ((max_pc < 4096) ? 3 : ((max_pc < 65536) ? 4 : ((max_pc < 65536*256) ? 6 : 8))); // #chars required for pc
3525   }
3526   int prefix_len = ((pc_digits + sb_chars + tab_size - 1)/tab_size)*tab_size;
3527 
3528   bool cut_short = false;
3529   st->print_cr("#");
3530   st->print("#  ");  C->tf()->dump_on(st);  st->cr();
3531   st->print_cr("#");
3532 
3533   // For all blocks
3534   int pc = 0x0;                 // Program counter
3535   char starts_bundle = ' ';
3536   C->regalloc()->dump_frame();
3537 
3538   Node *n = nullptr;
3539   for (uint i = 0; i < C->cfg()->number_of_blocks(); i++) {
3540     if (VMThread::should_terminate()) {
3541       cut_short = true;
3542       break;
3543     }
3544     Block* block = C->cfg()->get_block(i);
3545     if (block->is_connector() && !Verbose) {
3546       continue;
3547     }
3548     n = block->head();
3549     if ((pcs != nullptr) && (n->_idx < pc_limit)) {
3550       pc = pcs[n->_idx];
3551       st->print("%*.*x", pc_digits, pc_digits, pc);
3552     }
3553     st->fill_to(prefix_len);
3554     block->dump_head(C->cfg(), st);
3555     if (block->is_connector()) {
3556       st->fill_to(prefix_len);
3557       st->print_cr("# Empty connector block");
3558     } else if (block->num_preds() == 2 && block->pred(1)->is_CatchProj() && block->pred(1)->as_CatchProj()->_con == CatchProjNode::fall_through_index) {
3559       st->fill_to(prefix_len);
3560       st->print_cr("# Block is sole successor of call");
3561     }
3562 
3563     // For all instructions
3564     Node *delay = nullptr;
3565     for (uint j = 0; j < block->number_of_nodes(); j++) {
3566       if (VMThread::should_terminate()) {
3567         cut_short = true;
3568         break;
3569       }
3570       n = block->get_node(j);
3571       if (valid_bundle_info(n)) {
3572         Bundle* bundle = node_bundling(n);
3573         if (bundle->used_in_unconditional_delay()) {
3574           delay = n;
3575           continue;
3576         }
3577         if (bundle->starts_bundle()) {
3578           starts_bundle = '+';
3579         }
3580       }
3581 
3582       if (WizardMode) {
3583         n->dump();
3584       }
3585 
3586       if( !n->is_Region() &&    // Dont print in the Assembly
3587           !n->is_Phi() &&       // a few noisely useless nodes
3588           !n->is_Proj() &&
3589           !n->is_MachTemp() &&
3590           !n->is_SafePointScalarObject() &&
3591           !n->is_Catch() &&     // Would be nice to print exception table targets
3592           !n->is_MergeMem() &&  // Not very interesting
3593           !n->is_top() &&       // Debug info table constants
3594           !(n->is_Con() && !n->is_Mach())// Debug info table constants
3595           ) {
3596         if ((pcs != nullptr) && (n->_idx < pc_limit)) {
3597           pc = pcs[n->_idx];
3598           st->print("%*.*x", pc_digits, pc_digits, pc);
3599         } else {
3600           st->fill_to(pc_digits);
3601         }
3602         st->print(" %c ", starts_bundle);
3603         starts_bundle = ' ';
3604         st->fill_to(prefix_len);
3605         n->format(C->regalloc(), st);
3606         st->cr();
3607       }
3608 
3609       // If we have an instruction with a delay slot, and have seen a delay,
3610       // then back up and print it
3611       if (valid_bundle_info(n) && node_bundling(n)->use_unconditional_delay()) {
3612         // Coverity finding - Explicit null dereferenced.
3613         guarantee(delay != nullptr, "no unconditional delay instruction");
3614         if (WizardMode) delay->dump();
3615 
3616         if (node_bundling(delay)->starts_bundle())
3617           starts_bundle = '+';
3618         if ((pcs != nullptr) && (n->_idx < pc_limit)) {
3619           pc = pcs[n->_idx];
3620           st->print("%*.*x", pc_digits, pc_digits, pc);
3621         } else {
3622           st->fill_to(pc_digits);
3623         }
3624         st->print(" %c ", starts_bundle);
3625         starts_bundle = ' ';
3626         st->fill_to(prefix_len);
3627         delay->format(C->regalloc(), st);
3628         st->cr();
3629         delay = nullptr;
3630       }
3631 
3632       // Dump the exception table as well
3633       if( n->is_Catch() && (Verbose || WizardMode) ) {
3634         // Print the exception table for this offset
3635         _handler_table.print_subtable_for(pc);
3636       }
3637       st->bol(); // Make sure we start on a new line
3638     }
3639     st->cr(); // one empty line between blocks
3640     assert(cut_short || delay == nullptr, "no unconditional delay branch");
3641   } // End of per-block dump
3642 
3643   if (cut_short)  st->print_cr("*** disassembly is cut short ***");
3644 }
3645 #endif
3646 
3647 #ifndef PRODUCT
3648 void PhaseOutput::print_statistics() {
3649   Scheduling::print_statistics();
3650 }
3651 #endif