1 /*
   2  * Copyright (c) 1998, 2011, 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 "code/debugInfo.hpp"
  28 #include "code/debugInfoRec.hpp"
  29 #include "compiler/compileBroker.hpp"
  30 #include "compiler/oopMap.hpp"
  31 #include "memory/allocation.inline.hpp"
  32 #include "opto/callnode.hpp"
  33 #include "opto/cfgnode.hpp"
  34 #include "opto/locknode.hpp"
  35 #include "opto/machnode.hpp"
  36 #include "opto/output.hpp"
  37 #include "opto/regalloc.hpp"
  38 #include "opto/runtime.hpp"
  39 #include "opto/subnode.hpp"
  40 #include "opto/type.hpp"
  41 #include "runtime/handles.inline.hpp"
  42 #include "utilities/xmlstream.hpp"
  43 
  44 extern uint size_java_to_interp();
  45 extern uint reloc_java_to_interp();
  46 extern uint size_exception_handler();
  47 extern uint size_deopt_handler();
  48 
  49 #ifndef PRODUCT
  50 #define DEBUG_ARG(x) , x
  51 #else
  52 #define DEBUG_ARG(x)
  53 #endif
  54 
  55 extern int emit_exception_handler(CodeBuffer &cbuf);
  56 extern int emit_deopt_handler(CodeBuffer &cbuf);
  57 
  58 //------------------------------Output-----------------------------------------
  59 // Convert Nodes to instruction bits and pass off to the VM
  60 void Compile::Output() {
  61   // RootNode goes
  62   assert( _cfg->_broot->_nodes.size() == 0, "" );
  63 
  64   // The number of new nodes (mostly MachNop) is proportional to
  65   // the number of java calls and inner loops which are aligned.
  66   if ( C->check_node_count((NodeLimitFudgeFactor + C->java_calls()*3 +
  67                             C->inner_loops()*(OptoLoopAlignment-1)),
  68                            "out of nodes before code generation" ) ) {
  69     return;
  70   }
  71   // Make sure I can find the Start Node
  72   Block_Array& bbs = _cfg->_bbs;
  73   Block *entry = _cfg->_blocks[1];
  74   Block *broot = _cfg->_broot;
  75 
  76   const StartNode *start = entry->_nodes[0]->as_Start();
  77 
  78   // Replace StartNode with prolog
  79   MachPrologNode *prolog = new (this) MachPrologNode();
  80   entry->_nodes.map( 0, prolog );
  81   bbs.map( prolog->_idx, entry );
  82   bbs.map( start->_idx, NULL ); // start is no longer in any block
  83 
  84   // Virtual methods need an unverified entry point
  85 
  86   if( is_osr_compilation() ) {
  87     if( PoisonOSREntry ) {
  88       // TODO: Should use a ShouldNotReachHereNode...
  89       _cfg->insert( broot, 0, new (this) MachBreakpointNode() );
  90     }
  91   } else {
  92     if( _method && !_method->flags().is_static() ) {
  93       // Insert unvalidated entry point
  94       _cfg->insert( broot, 0, new (this) MachUEPNode() );
  95     }
  96 
  97   }
  98 
  99 
 100   // Break before main entry point
 101   if( (_method && _method->break_at_execute())
 102 #ifndef PRODUCT
 103     ||(OptoBreakpoint && is_method_compilation())
 104     ||(OptoBreakpointOSR && is_osr_compilation())
 105     ||(OptoBreakpointC2R && !_method)
 106 #endif
 107     ) {
 108     // checking for _method means that OptoBreakpoint does not apply to
 109     // runtime stubs or frame converters
 110     _cfg->insert( entry, 1, new (this) MachBreakpointNode() );
 111   }
 112 
 113   // Insert epilogs before every return
 114   for( uint i=0; i<_cfg->_num_blocks; i++ ) {
 115     Block *b = _cfg->_blocks[i];
 116     if( !b->is_connector() && b->non_connector_successor(0) == _cfg->_broot ) { // Found a program exit point?
 117       Node *m = b->end();
 118       if( m->is_Mach() && m->as_Mach()->ideal_Opcode() != Op_Halt ) {
 119         MachEpilogNode *epilog = new (this) MachEpilogNode(m->as_Mach()->ideal_Opcode() == Op_Return);
 120         b->add_inst( epilog );
 121         bbs.map(epilog->_idx, b);
 122         //_regalloc->set_bad(epilog->_idx); // Already initialized this way.
 123       }
 124     }
 125   }
 126 
 127 # ifdef ENABLE_ZAP_DEAD_LOCALS
 128   if ( ZapDeadCompiledLocals )  Insert_zap_nodes();
 129 # endif
 130 
 131   uint* blk_starts = NEW_RESOURCE_ARRAY(uint,_cfg->_num_blocks+1);
 132   blk_starts[0]    = 0;
 133 
 134   // Initialize code buffer and process short branches.
 135   CodeBuffer* cb = init_buffer(blk_starts);
 136 
 137   if (cb == NULL || failing())  return;
 138 
 139   ScheduleAndBundle();
 140 
 141 #ifndef PRODUCT
 142   if (trace_opto_output()) {
 143     tty->print("\n---- After ScheduleAndBundle ----\n");
 144     for (uint i = 0; i < _cfg->_num_blocks; i++) {
 145       tty->print("\nBB#%03d:\n", i);
 146       Block *bb = _cfg->_blocks[i];
 147       for (uint j = 0; j < bb->_nodes.size(); j++) {
 148         Node *n = bb->_nodes[j];
 149         OptoReg::Name reg = _regalloc->get_reg_first(n);
 150         tty->print(" %-6s ", reg >= 0 && reg < REG_COUNT ? Matcher::regName[reg] : "");
 151         n->dump();
 152       }
 153     }
 154   }
 155 #endif
 156 
 157   if (failing())  return;
 158 
 159   BuildOopMaps();
 160 
 161   if (failing())  return;
 162 
 163   fill_buffer(cb, blk_starts);
 164 }
 165 
 166 bool Compile::need_stack_bang(int frame_size_in_bytes) const {
 167   // Determine if we need to generate a stack overflow check.
 168   // Do it if the method is not a stub function and
 169   // has java calls or has frame size > vm_page_size/8.
 170   return (stub_function() == NULL &&
 171           (has_java_calls() || frame_size_in_bytes > os::vm_page_size()>>3));
 172 }
 173 
 174 bool Compile::need_register_stack_bang() const {
 175   // Determine if we need to generate a register stack overflow check.
 176   // This is only used on architectures which have split register
 177   // and memory stacks (ie. IA64).
 178   // Bang if the method is not a stub function and has java calls
 179   return (stub_function() == NULL && has_java_calls());
 180 }
 181 
 182 # ifdef ENABLE_ZAP_DEAD_LOCALS
 183 
 184 
 185 // In order to catch compiler oop-map bugs, we have implemented
 186 // a debugging mode called ZapDeadCompilerLocals.
 187 // This mode causes the compiler to insert a call to a runtime routine,
 188 // "zap_dead_locals", right before each place in compiled code
 189 // that could potentially be a gc-point (i.e., a safepoint or oop map point).
 190 // The runtime routine checks that locations mapped as oops are really
 191 // oops, that locations mapped as values do not look like oops,
 192 // and that locations mapped as dead are not used later
 193 // (by zapping them to an invalid address).
 194 
 195 int Compile::_CompiledZap_count = 0;
 196 
 197 void Compile::Insert_zap_nodes() {
 198   bool skip = false;
 199 
 200 
 201   // Dink with static counts because code code without the extra
 202   // runtime calls is MUCH faster for debugging purposes
 203 
 204        if ( CompileZapFirst  ==  0  ) ; // nothing special
 205   else if ( CompileZapFirst  >  CompiledZap_count() )  skip = true;
 206   else if ( CompileZapFirst  == CompiledZap_count() )
 207     warning("starting zap compilation after skipping");
 208 
 209        if ( CompileZapLast  ==  -1  ) ; // nothing special
 210   else if ( CompileZapLast  <   CompiledZap_count() )  skip = true;
 211   else if ( CompileZapLast  ==  CompiledZap_count() )
 212     warning("about to compile last zap");
 213 
 214   ++_CompiledZap_count; // counts skipped zaps, too
 215 
 216   if ( skip )  return;
 217 
 218 
 219   if ( _method == NULL )
 220     return; // no safepoints/oopmaps emitted for calls in stubs,so we don't care
 221 
 222   // Insert call to zap runtime stub before every node with an oop map
 223   for( uint i=0; i<_cfg->_num_blocks; i++ ) {
 224     Block *b = _cfg->_blocks[i];
 225     for ( uint j = 0;  j < b->_nodes.size();  ++j ) {
 226       Node *n = b->_nodes[j];
 227 
 228       // Determining if we should insert a zap-a-lot node in output.
 229       // We do that for all nodes that has oopmap info, except for calls
 230       // to allocation.  Calls to allocation passes in the old top-of-eden pointer
 231       // and expect the C code to reset it.  Hence, there can be no safepoints between
 232       // the inlined-allocation and the call to new_Java, etc.
 233       // We also cannot zap monitor calls, as they must hold the microlock
 234       // during the call to Zap, which also wants to grab the microlock.
 235       bool insert = n->is_MachSafePoint() && (n->as_MachSafePoint()->oop_map() != NULL);
 236       if ( insert ) { // it is MachSafePoint
 237         if ( !n->is_MachCall() ) {
 238           insert = false;
 239         } else if ( n->is_MachCall() ) {
 240           MachCallNode* call = n->as_MachCall();
 241           if (call->entry_point() == OptoRuntime::new_instance_Java() ||
 242               call->entry_point() == OptoRuntime::new_array_Java() ||
 243               call->entry_point() == OptoRuntime::multianewarray2_Java() ||
 244               call->entry_point() == OptoRuntime::multianewarray3_Java() ||
 245               call->entry_point() == OptoRuntime::multianewarray4_Java() ||
 246               call->entry_point() == OptoRuntime::multianewarray5_Java() ||
 247               call->entry_point() == OptoRuntime::slow_arraycopy_Java() ||
 248               call->entry_point() == OptoRuntime::complete_monitor_locking_Java()
 249               ) {
 250             insert = false;
 251           }
 252         }
 253         if (insert) {
 254           Node *zap = call_zap_node(n->as_MachSafePoint(), i);
 255           b->_nodes.insert( j, zap );
 256           _cfg->_bbs.map( zap->_idx, b );
 257           ++j;
 258         }
 259       }
 260     }
 261   }
 262 }
 263 
 264 
 265 Node* Compile::call_zap_node(MachSafePointNode* node_to_check, int block_no) {
 266   const TypeFunc *tf = OptoRuntime::zap_dead_locals_Type();
 267   CallStaticJavaNode* ideal_node =
 268     new (this, tf->domain()->cnt()) CallStaticJavaNode( tf,
 269          OptoRuntime::zap_dead_locals_stub(_method->flags().is_native()),
 270                             "call zap dead locals stub", 0, TypePtr::BOTTOM);
 271   // We need to copy the OopMap from the site we're zapping at.
 272   // We have to make a copy, because the zap site might not be
 273   // a call site, and zap_dead is a call site.
 274   OopMap* clone = node_to_check->oop_map()->deep_copy();
 275 
 276   // Add the cloned OopMap to the zap node
 277   ideal_node->set_oop_map(clone);
 278   return _matcher->match_sfpt(ideal_node);
 279 }
 280 
 281 //------------------------------is_node_getting_a_safepoint--------------------
 282 bool Compile::is_node_getting_a_safepoint( Node* n) {
 283   // This code duplicates the logic prior to the call of add_safepoint
 284   // below in this file.
 285   if( n->is_MachSafePoint() ) return true;
 286   return false;
 287 }
 288 
 289 # endif // ENABLE_ZAP_DEAD_LOCALS
 290 
 291 //------------------------------compute_loop_first_inst_sizes------------------
 292 // Compute the size of first NumberOfLoopInstrToAlign instructions at the top
 293 // of a loop. When aligning a loop we need to provide enough instructions
 294 // in cpu's fetch buffer to feed decoders. The loop alignment could be
 295 // avoided if we have enough instructions in fetch buffer at the head of a loop.
 296 // By default, the size is set to 999999 by Block's constructor so that
 297 // a loop will be aligned if the size is not reset here.
 298 //
 299 // Note: Mach instructions could contain several HW instructions
 300 // so the size is estimated only.
 301 //
 302 void Compile::compute_loop_first_inst_sizes() {
 303   // The next condition is used to gate the loop alignment optimization.
 304   // Don't aligned a loop if there are enough instructions at the head of a loop
 305   // or alignment padding is larger then MaxLoopPad. By default, MaxLoopPad
 306   // is equal to OptoLoopAlignment-1 except on new Intel cpus, where it is
 307   // equal to 11 bytes which is the largest address NOP instruction.
 308   if( MaxLoopPad < OptoLoopAlignment-1 ) {
 309     uint last_block = _cfg->_num_blocks-1;
 310     for( uint i=1; i <= last_block; i++ ) {
 311       Block *b = _cfg->_blocks[i];
 312       // Check the first loop's block which requires an alignment.
 313       if( b->loop_alignment() > (uint)relocInfo::addr_unit() ) {
 314         uint sum_size = 0;
 315         uint inst_cnt = NumberOfLoopInstrToAlign;
 316         inst_cnt = b->compute_first_inst_size(sum_size, inst_cnt, _regalloc);
 317 
 318         // Check subsequent fallthrough blocks if the loop's first
 319         // block(s) does not have enough instructions.
 320         Block *nb = b;
 321         while( inst_cnt > 0 &&
 322                i < last_block &&
 323                !_cfg->_blocks[i+1]->has_loop_alignment() &&
 324                !nb->has_successor(b) ) {
 325           i++;
 326           nb = _cfg->_blocks[i];
 327           inst_cnt  = nb->compute_first_inst_size(sum_size, inst_cnt, _regalloc);
 328         } // while( inst_cnt > 0 && i < last_block  )
 329 
 330         b->set_first_inst_size(sum_size);
 331       } // f( b->head()->is_Loop() )
 332     } // for( i <= last_block )
 333   } // if( MaxLoopPad < OptoLoopAlignment-1 )
 334 }
 335 
 336 //----------------------shorten_branches---------------------------------------
 337 // The architecture description provides short branch variants for some long
 338 // branch instructions. Replace eligible long branches with short branches.
 339 void Compile::shorten_branches(uint* blk_starts, int& code_size, int& reloc_size, int& stub_size) {
 340 
 341   // ------------------
 342   // Compute size of each block, method size, and relocation information size
 343   uint nblocks  = _cfg->_num_blocks;
 344 
 345   uint*      jmp_offset = NEW_RESOURCE_ARRAY(uint,nblocks);
 346   uint*      jmp_size   = NEW_RESOURCE_ARRAY(uint,nblocks);
 347   int*       jmp_nidx   = NEW_RESOURCE_ARRAY(int ,nblocks);
 348   DEBUG_ONLY( uint *jmp_target = NEW_RESOURCE_ARRAY(uint,nblocks); )
 349   DEBUG_ONLY( uint *jmp_rule = NEW_RESOURCE_ARRAY(uint,nblocks); )
 350 
 351   bool has_short_branch_candidate = false;
 352 
 353   // Initialize the sizes to 0
 354   code_size  = 0;          // Size in bytes of generated code
 355   stub_size  = 0;          // Size in bytes of all stub entries
 356   // Size in bytes of all relocation entries, including those in local stubs.
 357   // Start with 2-bytes of reloc info for the unvalidated entry point
 358   reloc_size = 1;          // Number of relocation entries
 359 
 360   // Make three passes.  The first computes pessimistic blk_starts,
 361   // relative jmp_offset and reloc_size information.  The second performs
 362   // short branch substitution using the pessimistic sizing.  The
 363   // third inserts nops where needed.
 364 
 365   // Step one, perform a pessimistic sizing pass.
 366   uint last_call_adr = max_uint;
 367   uint last_avoid_back_to_back_adr = max_uint;
 368   uint nop_size = (new (this) MachNopNode())->size(_regalloc);
 369   for (uint i = 0; i < nblocks; i++) { // For all blocks
 370     Block *b = _cfg->_blocks[i];
 371 
 372     // During short branch replacement, we store the relative (to blk_starts)
 373     // offset of jump in jmp_offset, rather than the absolute offset of jump.
 374     // This is so that we do not need to recompute sizes of all nodes when
 375     // we compute correct blk_starts in our next sizing pass.
 376     jmp_offset[i] = 0;
 377     jmp_size[i]   = 0;
 378     jmp_nidx[i]   = -1;
 379     DEBUG_ONLY( jmp_target[i] = 0; )
 380     DEBUG_ONLY( jmp_rule[i]   = 0; )
 381 
 382     // Sum all instruction sizes to compute block size
 383     uint last_inst = b->_nodes.size();
 384     uint blk_size = 0;
 385     for (uint j = 0; j < last_inst; j++) {
 386       Node* nj = b->_nodes[j];
 387       // Handle machine instruction nodes
 388       if (nj->is_Mach()) {
 389         MachNode *mach = nj->as_Mach();
 390         blk_size += (mach->alignment_required() - 1) * relocInfo::addr_unit(); // assume worst case padding
 391         reloc_size += mach->reloc();
 392         if( mach->is_MachCall() ) {
 393           MachCallNode *mcall = mach->as_MachCall();
 394           // This destination address is NOT PC-relative
 395 
 396           mcall->method_set((intptr_t)mcall->entry_point());
 397 
 398           if( mcall->is_MachCallJava() && mcall->as_MachCallJava()->_method ) {
 399             stub_size  += size_java_to_interp();
 400             reloc_size += reloc_java_to_interp();
 401           }
 402         } else if (mach->is_MachSafePoint()) {
 403           // If call/safepoint are adjacent, account for possible
 404           // nop to disambiguate the two safepoints.
 405           // ScheduleAndBundle() can rearrange nodes in a block,
 406           // check for all offsets inside this block.
 407           if (last_call_adr >= blk_starts[i]) {
 408             blk_size += nop_size;
 409           }
 410         }
 411         if (mach->avoid_back_to_back()) {
 412           // Nop is inserted between "avoid back to back" instructions.
 413           // ScheduleAndBundle() can rearrange nodes in a block,
 414           // check for all offsets inside this block.
 415           if (last_avoid_back_to_back_adr >= blk_starts[i]) {
 416             blk_size += nop_size;
 417           }
 418         }
 419         if (mach->may_be_short_branch()) {
 420           if (!nj->is_MachBranch()) {
 421 #ifndef PRODUCT
 422             nj->dump(3);
 423 #endif
 424             Unimplemented();
 425           }
 426           assert(jmp_nidx[i] == -1, "block should have only one branch");
 427           jmp_offset[i] = blk_size;
 428           jmp_size[i]   = nj->size(_regalloc);
 429           jmp_nidx[i]   = j;
 430           has_short_branch_candidate = true;
 431         }
 432       }
 433       blk_size += nj->size(_regalloc);
 434       // Remember end of call offset
 435       if (nj->is_MachCall() && !nj->is_MachCallLeaf()) {
 436         last_call_adr = blk_starts[i]+blk_size;
 437       }
 438       // Remember end of avoid_back_to_back offset
 439       if (nj->is_Mach() && nj->as_Mach()->avoid_back_to_back()) {
 440         last_avoid_back_to_back_adr = blk_starts[i]+blk_size;
 441       }
 442     }
 443 
 444     // When the next block starts a loop, we may insert pad NOP
 445     // instructions.  Since we cannot know our future alignment,
 446     // assume the worst.
 447     if (i< nblocks-1) {
 448       Block *nb = _cfg->_blocks[i+1];
 449       int max_loop_pad = nb->code_alignment()-relocInfo::addr_unit();
 450       if (max_loop_pad > 0) {
 451         assert(is_power_of_2(max_loop_pad+relocInfo::addr_unit()), "");
 452         blk_size += max_loop_pad;
 453       }
 454     }
 455 
 456     // Save block size; update total method size
 457     blk_starts[i+1] = blk_starts[i]+blk_size;
 458   }
 459 
 460   // Step two, replace eligible long jumps.
 461   bool progress = true;
 462   uint last_may_be_short_branch_adr = max_uint;
 463   while (has_short_branch_candidate && progress) {
 464     progress = false;
 465     has_short_branch_candidate = false;
 466     int adjust_block_start = 0;
 467     for (uint i = 0; i < nblocks; i++) {
 468       Block *b = _cfg->_blocks[i];
 469       int idx = jmp_nidx[i];
 470       MachNode* mach = (idx == -1) ? NULL: b->_nodes[idx]->as_Mach();
 471       if (mach != NULL && mach->may_be_short_branch()) {
 472 #ifdef ASSERT
 473         assert(jmp_size[i] > 0 && mach->is_MachBranch(), "sanity");
 474         int j;
 475         // Find the branch; ignore trailing NOPs.
 476         for (j = b->_nodes.size()-1; j>=0; j--) {
 477           Node* n = b->_nodes[j];
 478           if (!n->is_Mach() || n->as_Mach()->ideal_Opcode() != Op_Con)
 479             break;
 480         }
 481         assert(j >= 0 && j == idx && b->_nodes[j] == (Node*)mach, "sanity");
 482 #endif
 483         int br_size = jmp_size[i];
 484         int br_offs = blk_starts[i] + jmp_offset[i];
 485 
 486         // This requires the TRUE branch target be in succs[0]
 487         uint bnum = b->non_connector_successor(0)->_pre_order;
 488         int offset = blk_starts[bnum] - br_offs;
 489         if (bnum > i) { // adjust following block's offset
 490           offset -= adjust_block_start;
 491         }
 492         // In the following code a nop could be inserted before
 493         // the branch which will increase the backward distance.
 494         bool needs_padding = ((uint)br_offs == last_may_be_short_branch_adr);
 495         if (needs_padding && offset <= 0)
 496           offset -= nop_size;
 497 
 498         if (_matcher->is_short_branch_offset(mach->rule(), br_size, offset)) {
 499           // We've got a winner.  Replace this branch.
 500           MachNode* replacement = mach->as_MachBranch()->short_branch_version(this);
 501 
 502           // Update the jmp_size.
 503           int new_size = replacement->size(_regalloc);
 504           int diff     = br_size - new_size;
 505           assert(diff >= (int)nop_size, "short_branch size should be smaller");
 506           // Conservatively take into accound padding between
 507           // avoid_back_to_back branches. Previous branch could be
 508           // converted into avoid_back_to_back branch during next
 509           // rounds.
 510           if (needs_padding && replacement->avoid_back_to_back()) {
 511             jmp_offset[i] += nop_size;
 512             diff -= nop_size;
 513           }
 514           adjust_block_start += diff;
 515           b->_nodes.map(idx, replacement);
 516           mach->subsume_by(replacement);
 517           mach = replacement;
 518           progress = true;
 519 
 520           jmp_size[i] = new_size;
 521           DEBUG_ONLY( jmp_target[i] = bnum; );
 522           DEBUG_ONLY( jmp_rule[i] = mach->rule(); );
 523         } else {
 524           // The jump distance is not short, try again during next iteration.
 525           has_short_branch_candidate = true;
 526         }
 527       } // (mach->may_be_short_branch())
 528       if (mach != NULL && (mach->may_be_short_branch() ||
 529                            mach->avoid_back_to_back())) {
 530         last_may_be_short_branch_adr = blk_starts[i] + jmp_offset[i] + jmp_size[i];
 531       }
 532       blk_starts[i+1] -= adjust_block_start;
 533     }
 534   }
 535 
 536 #ifdef ASSERT
 537   for (uint i = 0; i < nblocks; i++) { // For all blocks
 538     if (jmp_target[i] != 0) {
 539       int br_size = jmp_size[i];
 540       int offset = blk_starts[jmp_target[i]]-(blk_starts[i] + jmp_offset[i]);
 541       if (!_matcher->is_short_branch_offset(jmp_rule[i], br_size, offset)) {
 542         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]);
 543       }
 544       assert(_matcher->is_short_branch_offset(jmp_rule[i], br_size, offset), "Displacement too large for short jmp");
 545     }
 546   }
 547 #endif
 548 
 549   // Step 3, compute the offsets of all blocks, will be done in fill_buffer()
 550   // after ScheduleAndBundle().
 551 
 552   // ------------------
 553   // Compute size for code buffer
 554   code_size = blk_starts[nblocks];
 555 
 556   // Relocation records
 557   reloc_size += 1;              // Relo entry for exception handler
 558 
 559   // Adjust reloc_size to number of record of relocation info
 560   // Min is 2 bytes, max is probably 6 or 8, with a tax up to 25% for
 561   // a relocation index.
 562   // The CodeBuffer will expand the locs array if this estimate is too low.
 563   reloc_size *= 10 / sizeof(relocInfo);
 564 }
 565 
 566 //------------------------------FillLocArray-----------------------------------
 567 // Create a bit of debug info and append it to the array.  The mapping is from
 568 // Java local or expression stack to constant, register or stack-slot.  For
 569 // doubles, insert 2 mappings and return 1 (to tell the caller that the next
 570 // entry has been taken care of and caller should skip it).
 571 static LocationValue *new_loc_value( PhaseRegAlloc *ra, OptoReg::Name regnum, Location::Type l_type ) {
 572   // This should never have accepted Bad before
 573   assert(OptoReg::is_valid(regnum), "location must be valid");
 574   return (OptoReg::is_reg(regnum))
 575     ? new LocationValue(Location::new_reg_loc(l_type, OptoReg::as_VMReg(regnum)) )
 576     : new LocationValue(Location::new_stk_loc(l_type,  ra->reg2offset(regnum)));
 577 }
 578 
 579 
 580 ObjectValue*
 581 Compile::sv_for_node_id(GrowableArray<ScopeValue*> *objs, int id) {
 582   for (int i = 0; i < objs->length(); i++) {
 583     assert(objs->at(i)->is_object(), "corrupt object cache");
 584     ObjectValue* sv = (ObjectValue*) objs->at(i);
 585     if (sv->id() == id) {
 586       return sv;
 587     }
 588   }
 589   // Otherwise..
 590   return NULL;
 591 }
 592 
 593 void Compile::set_sv_for_object_node(GrowableArray<ScopeValue*> *objs,
 594                                      ObjectValue* sv ) {
 595   assert(sv_for_node_id(objs, sv->id()) == NULL, "Precondition");
 596   objs->append(sv);
 597 }
 598 
 599 
 600 void Compile::FillLocArray( int idx, MachSafePointNode* sfpt, Node *local,
 601                             GrowableArray<ScopeValue*> *array,
 602                             GrowableArray<ScopeValue*> *objs ) {
 603   assert( local, "use _top instead of null" );
 604   if (array->length() != idx) {
 605     assert(array->length() == idx + 1, "Unexpected array count");
 606     // Old functionality:
 607     //   return
 608     // New functionality:
 609     //   Assert if the local is not top. In product mode let the new node
 610     //   override the old entry.
 611     assert(local == top(), "LocArray collision");
 612     if (local == top()) {
 613       return;
 614     }
 615     array->pop();
 616   }
 617   const Type *t = local->bottom_type();
 618 
 619   // Is it a safepoint scalar object node?
 620   if (local->is_SafePointScalarObject()) {
 621     SafePointScalarObjectNode* spobj = local->as_SafePointScalarObject();
 622 
 623     ObjectValue* sv = Compile::sv_for_node_id(objs, spobj->_idx);
 624     if (sv == NULL) {
 625       ciKlass* cik = t->is_oopptr()->klass();
 626       assert(cik->is_instance_klass() ||
 627              cik->is_array_klass(), "Not supported allocation.");
 628       sv = new ObjectValue(spobj->_idx,
 629                            new ConstantOopWriteValue(cik->constant_encoding()));
 630       Compile::set_sv_for_object_node(objs, sv);
 631 
 632       uint first_ind = spobj->first_index();
 633       for (uint i = 0; i < spobj->n_fields(); i++) {
 634         Node* fld_node = sfpt->in(first_ind+i);
 635         (void)FillLocArray(sv->field_values()->length(), sfpt, fld_node, sv->field_values(), objs);
 636       }
 637     }
 638     array->append(sv);
 639     return;
 640   }
 641 
 642   // Grab the register number for the local
 643   OptoReg::Name regnum = _regalloc->get_reg_first(local);
 644   if( OptoReg::is_valid(regnum) ) {// Got a register/stack?
 645     // Record the double as two float registers.
 646     // The register mask for such a value always specifies two adjacent
 647     // float registers, with the lower register number even.
 648     // Normally, the allocation of high and low words to these registers
 649     // is irrelevant, because nearly all operations on register pairs
 650     // (e.g., StoreD) treat them as a single unit.
 651     // Here, we assume in addition that the words in these two registers
 652     // stored "naturally" (by operations like StoreD and double stores
 653     // within the interpreter) such that the lower-numbered register
 654     // is written to the lower memory address.  This may seem like
 655     // a machine dependency, but it is not--it is a requirement on
 656     // the author of the <arch>.ad file to ensure that, for every
 657     // even/odd double-register pair to which a double may be allocated,
 658     // the word in the even single-register is stored to the first
 659     // memory word.  (Note that register numbers are completely
 660     // arbitrary, and are not tied to any machine-level encodings.)
 661 #ifdef _LP64
 662     if( t->base() == Type::DoubleBot || t->base() == Type::DoubleCon ) {
 663       array->append(new ConstantIntValue(0));
 664       array->append(new_loc_value( _regalloc, regnum, Location::dbl ));
 665     } else if ( t->base() == Type::Long ) {
 666       array->append(new ConstantIntValue(0));
 667       array->append(new_loc_value( _regalloc, regnum, Location::lng ));
 668     } else if ( t->base() == Type::RawPtr ) {
 669       // jsr/ret return address which must be restored into a the full
 670       // width 64-bit stack slot.
 671       array->append(new_loc_value( _regalloc, regnum, Location::lng ));
 672     }
 673 #else //_LP64
 674 #ifdef SPARC
 675     if (t->base() == Type::Long && OptoReg::is_reg(regnum)) {
 676       // For SPARC we have to swap high and low words for
 677       // long values stored in a single-register (g0-g7).
 678       array->append(new_loc_value( _regalloc,              regnum   , Location::normal ));
 679       array->append(new_loc_value( _regalloc, OptoReg::add(regnum,1), Location::normal ));
 680     } else
 681 #endif //SPARC
 682     if( t->base() == Type::DoubleBot || t->base() == Type::DoubleCon || t->base() == Type::Long ) {
 683       // Repack the double/long as two jints.
 684       // The convention the interpreter uses is that the second local
 685       // holds the first raw word of the native double representation.
 686       // This is actually reasonable, since locals and stack arrays
 687       // grow downwards in all implementations.
 688       // (If, on some machine, the interpreter's Java locals or stack
 689       // were to grow upwards, the embedded doubles would be word-swapped.)
 690       array->append(new_loc_value( _regalloc, OptoReg::add(regnum,1), Location::normal ));
 691       array->append(new_loc_value( _regalloc,              regnum   , Location::normal ));
 692     }
 693 #endif //_LP64
 694     else if( (t->base() == Type::FloatBot || t->base() == Type::FloatCon) &&
 695                OptoReg::is_reg(regnum) ) {
 696       array->append(new_loc_value( _regalloc, regnum, Matcher::float_in_double()
 697                                    ? Location::float_in_dbl : Location::normal ));
 698     } else if( t->base() == Type::Int && OptoReg::is_reg(regnum) ) {
 699       array->append(new_loc_value( _regalloc, regnum, Matcher::int_in_long
 700                                    ? Location::int_in_long : Location::normal ));
 701     } else if( t->base() == Type::NarrowOop ) {
 702       array->append(new_loc_value( _regalloc, regnum, Location::narrowoop ));
 703     } else {
 704       array->append(new_loc_value( _regalloc, regnum, _regalloc->is_oop(local) ? Location::oop : Location::normal ));
 705     }
 706     return;
 707   }
 708 
 709   // No register.  It must be constant data.
 710   switch (t->base()) {
 711   case Type::Half:              // Second half of a double
 712     ShouldNotReachHere();       // Caller should skip 2nd halves
 713     break;
 714   case Type::AnyPtr:
 715     array->append(new ConstantOopWriteValue(NULL));
 716     break;
 717   case Type::AryPtr:
 718   case Type::InstPtr:
 719   case Type::KlassPtr:          // fall through
 720     array->append(new ConstantOopWriteValue(t->isa_oopptr()->const_oop()->constant_encoding()));
 721     break;
 722   case Type::NarrowOop:
 723     if (t == TypeNarrowOop::NULL_PTR) {
 724       array->append(new ConstantOopWriteValue(NULL));
 725     } else {
 726       array->append(new ConstantOopWriteValue(t->make_ptr()->isa_oopptr()->const_oop()->constant_encoding()));
 727     }
 728     break;
 729   case Type::Int:
 730     array->append(new ConstantIntValue(t->is_int()->get_con()));
 731     break;
 732   case Type::RawPtr:
 733     // A return address (T_ADDRESS).
 734     assert((intptr_t)t->is_ptr()->get_con() < (intptr_t)0x10000, "must be a valid BCI");
 735 #ifdef _LP64
 736     // Must be restored to the full-width 64-bit stack slot.
 737     array->append(new ConstantLongValue(t->is_ptr()->get_con()));
 738 #else
 739     array->append(new ConstantIntValue(t->is_ptr()->get_con()));
 740 #endif
 741     break;
 742   case Type::FloatCon: {
 743     float f = t->is_float_constant()->getf();
 744     array->append(new ConstantIntValue(jint_cast(f)));
 745     break;
 746   }
 747   case Type::DoubleCon: {
 748     jdouble d = t->is_double_constant()->getd();
 749 #ifdef _LP64
 750     array->append(new ConstantIntValue(0));
 751     array->append(new ConstantDoubleValue(d));
 752 #else
 753     // Repack the double as two jints.
 754     // The convention the interpreter uses is that the second local
 755     // holds the first raw word of the native double representation.
 756     // This is actually reasonable, since locals and stack arrays
 757     // grow downwards in all implementations.
 758     // (If, on some machine, the interpreter's Java locals or stack
 759     // were to grow upwards, the embedded doubles would be word-swapped.)
 760     jint   *dp = (jint*)&d;
 761     array->append(new ConstantIntValue(dp[1]));
 762     array->append(new ConstantIntValue(dp[0]));
 763 #endif
 764     break;
 765   }
 766   case Type::Long: {
 767     jlong d = t->is_long()->get_con();
 768 #ifdef _LP64
 769     array->append(new ConstantIntValue(0));
 770     array->append(new ConstantLongValue(d));
 771 #else
 772     // Repack the long as two jints.
 773     // The convention the interpreter uses is that the second local
 774     // holds the first raw word of the native double representation.
 775     // This is actually reasonable, since locals and stack arrays
 776     // grow downwards in all implementations.
 777     // (If, on some machine, the interpreter's Java locals or stack
 778     // were to grow upwards, the embedded doubles would be word-swapped.)
 779     jint *dp = (jint*)&d;
 780     array->append(new ConstantIntValue(dp[1]));
 781     array->append(new ConstantIntValue(dp[0]));
 782 #endif
 783     break;
 784   }
 785   case Type::Top:               // Add an illegal value here
 786     array->append(new LocationValue(Location()));
 787     break;
 788   default:
 789     ShouldNotReachHere();
 790     break;
 791   }
 792 }
 793 
 794 // Determine if this node starts a bundle
 795 bool Compile::starts_bundle(const Node *n) const {
 796   return (_node_bundling_limit > n->_idx &&
 797           _node_bundling_base[n->_idx].starts_bundle());
 798 }
 799 
 800 //--------------------------Process_OopMap_Node--------------------------------
 801 void Compile::Process_OopMap_Node(MachNode *mach, int current_offset) {
 802 
 803   // Handle special safepoint nodes for synchronization
 804   MachSafePointNode *sfn   = mach->as_MachSafePoint();
 805   MachCallNode      *mcall;
 806 
 807 #ifdef ENABLE_ZAP_DEAD_LOCALS
 808   assert( is_node_getting_a_safepoint(mach),  "logic does not match; false negative");
 809 #endif
 810 
 811   int safepoint_pc_offset = current_offset;
 812   bool is_method_handle_invoke = false;
 813   bool return_oop = false;
 814 
 815   // Add the safepoint in the DebugInfoRecorder
 816   if( !mach->is_MachCall() ) {
 817     mcall = NULL;
 818     debug_info()->add_safepoint(safepoint_pc_offset, sfn->_oop_map);
 819   } else {
 820     mcall = mach->as_MachCall();
 821 
 822     // Is the call a MethodHandle call?
 823     if (mcall->is_MachCallJava()) {
 824       if (mcall->as_MachCallJava()->_method_handle_invoke) {
 825         assert(has_method_handle_invokes(), "must have been set during call generation");
 826         is_method_handle_invoke = true;
 827       }
 828     }
 829 
 830     // Check if a call returns an object.
 831     if (mcall->return_value_is_used() &&
 832         mcall->tf()->range()->field_at(TypeFunc::Parms)->isa_ptr()) {
 833       return_oop = true;
 834     }
 835     safepoint_pc_offset += mcall->ret_addr_offset();
 836     debug_info()->add_safepoint(safepoint_pc_offset, mcall->_oop_map);
 837   }
 838 
 839   // Loop over the JVMState list to add scope information
 840   // Do not skip safepoints with a NULL method, they need monitor info
 841   JVMState* youngest_jvms = sfn->jvms();
 842   int max_depth = youngest_jvms->depth();
 843 
 844   // Allocate the object pool for scalar-replaced objects -- the map from
 845   // small-integer keys (which can be recorded in the local and ostack
 846   // arrays) to descriptions of the object state.
 847   GrowableArray<ScopeValue*> *objs = new GrowableArray<ScopeValue*>();
 848 
 849   // Visit scopes from oldest to youngest.
 850   for (int depth = 1; depth <= max_depth; depth++) {
 851     JVMState* jvms = youngest_jvms->of_depth(depth);
 852     int idx;
 853     ciMethod* method = jvms->has_method() ? jvms->method() : NULL;
 854     // Safepoints that do not have method() set only provide oop-map and monitor info
 855     // to support GC; these do not support deoptimization.
 856     int num_locs = (method == NULL) ? 0 : jvms->loc_size();
 857     int num_exps = (method == NULL) ? 0 : jvms->stk_size();
 858     int num_mon  = jvms->nof_monitors();
 859     assert(method == NULL || jvms->bci() < 0 || num_locs == method->max_locals(),
 860            "JVMS local count must match that of the method");
 861 
 862     // Add Local and Expression Stack Information
 863 
 864     // Insert locals into the locarray
 865     GrowableArray<ScopeValue*> *locarray = new GrowableArray<ScopeValue*>(num_locs);
 866     for( idx = 0; idx < num_locs; idx++ ) {
 867       FillLocArray( idx, sfn, sfn->local(jvms, idx), locarray, objs );
 868     }
 869 
 870     // Insert expression stack entries into the exparray
 871     GrowableArray<ScopeValue*> *exparray = new GrowableArray<ScopeValue*>(num_exps);
 872     for( idx = 0; idx < num_exps; idx++ ) {
 873       FillLocArray( idx,  sfn, sfn->stack(jvms, idx), exparray, objs );
 874     }
 875 
 876     // Add in mappings of the monitors
 877     assert( !method ||
 878             !method->is_synchronized() ||
 879             method->is_native() ||
 880             num_mon > 0 ||
 881             !GenerateSynchronizationCode,
 882             "monitors must always exist for synchronized methods");
 883 
 884     // Build the growable array of ScopeValues for exp stack
 885     GrowableArray<MonitorValue*> *monarray = new GrowableArray<MonitorValue*>(num_mon);
 886 
 887     // Loop over monitors and insert into array
 888     for(idx = 0; idx < num_mon; idx++) {
 889       // Grab the node that defines this monitor
 890       Node* box_node = sfn->monitor_box(jvms, idx);
 891       Node* obj_node = sfn->monitor_obj(jvms, idx);
 892 
 893       // Create ScopeValue for object
 894       ScopeValue *scval = NULL;
 895 
 896       if( obj_node->is_SafePointScalarObject() ) {
 897         SafePointScalarObjectNode* spobj = obj_node->as_SafePointScalarObject();
 898         scval = Compile::sv_for_node_id(objs, spobj->_idx);
 899         if (scval == NULL) {
 900           const Type *t = obj_node->bottom_type();
 901           ciKlass* cik = t->is_oopptr()->klass();
 902           assert(cik->is_instance_klass() ||
 903                  cik->is_array_klass(), "Not supported allocation.");
 904           ObjectValue* sv = new ObjectValue(spobj->_idx,
 905                                 new ConstantOopWriteValue(cik->constant_encoding()));
 906           Compile::set_sv_for_object_node(objs, sv);
 907 
 908           uint first_ind = spobj->first_index();
 909           for (uint i = 0; i < spobj->n_fields(); i++) {
 910             Node* fld_node = sfn->in(first_ind+i);
 911             (void)FillLocArray(sv->field_values()->length(), sfn, fld_node, sv->field_values(), objs);
 912           }
 913           scval = sv;
 914         }
 915       } else if( !obj_node->is_Con() ) {
 916         OptoReg::Name obj_reg = _regalloc->get_reg_first(obj_node);
 917         if( obj_node->bottom_type()->base() == Type::NarrowOop ) {
 918           scval = new_loc_value( _regalloc, obj_reg, Location::narrowoop );
 919         } else {
 920           scval = new_loc_value( _regalloc, obj_reg, Location::oop );
 921         }
 922       } else {
 923         const TypePtr *tp = obj_node->bottom_type()->make_ptr();
 924         scval = new ConstantOopWriteValue(tp->is_oopptr()->const_oop()->constant_encoding());
 925       }
 926 
 927       OptoReg::Name box_reg = BoxLockNode::stack_slot(box_node);
 928       Location basic_lock = Location::new_stk_loc(Location::normal,_regalloc->reg2offset(box_reg));
 929       while( !box_node->is_BoxLock() )  box_node = box_node->in(1);
 930       monarray->append(new MonitorValue(scval, basic_lock, box_node->as_BoxLock()->is_eliminated()));
 931     }
 932 
 933     // We dump the object pool first, since deoptimization reads it in first.
 934     debug_info()->dump_object_pool(objs);
 935 
 936     // Build first class objects to pass to scope
 937     DebugToken *locvals = debug_info()->create_scope_values(locarray);
 938     DebugToken *expvals = debug_info()->create_scope_values(exparray);
 939     DebugToken *monvals = debug_info()->create_monitor_values(monarray);
 940 
 941     // Make method available for all Safepoints
 942     ciMethod* scope_method = method ? method : _method;
 943     // Describe the scope here
 944     assert(jvms->bci() >= InvocationEntryBci && jvms->bci() <= 0x10000, "must be a valid or entry BCI");
 945     assert(!jvms->should_reexecute() || depth == max_depth, "reexecute allowed only for the youngest");
 946     // Now we can describe the scope.
 947     debug_info()->describe_scope(safepoint_pc_offset, scope_method, jvms->bci(), jvms->should_reexecute(), is_method_handle_invoke, false, return_oop, locvals, expvals, monvals);
 948   } // End jvms loop
 949 
 950   // Mark the end of the scope set.
 951   debug_info()->end_safepoint(safepoint_pc_offset);
 952 }
 953 
 954 
 955 
 956 // A simplified version of Process_OopMap_Node, to handle non-safepoints.
 957 class NonSafepointEmitter {
 958   Compile*  C;
 959   JVMState* _pending_jvms;
 960   int       _pending_offset;
 961 
 962   void emit_non_safepoint();
 963 
 964  public:
 965   NonSafepointEmitter(Compile* compile) {
 966     this->C = compile;
 967     _pending_jvms = NULL;
 968     _pending_offset = 0;
 969   }
 970 
 971   void observe_instruction(Node* n, int pc_offset) {
 972     if (!C->debug_info()->recording_non_safepoints())  return;
 973 
 974     Node_Notes* nn = C->node_notes_at(n->_idx);
 975     if (nn == NULL || nn->jvms() == NULL)  return;
 976     if (_pending_jvms != NULL &&
 977         _pending_jvms->same_calls_as(nn->jvms())) {
 978       // Repeated JVMS?  Stretch it up here.
 979       _pending_offset = pc_offset;
 980     } else {
 981       if (_pending_jvms != NULL &&
 982           _pending_offset < pc_offset) {
 983         emit_non_safepoint();
 984       }
 985       _pending_jvms = NULL;
 986       if (pc_offset > C->debug_info()->last_pc_offset()) {
 987         // This is the only way _pending_jvms can become non-NULL:
 988         _pending_jvms = nn->jvms();
 989         _pending_offset = pc_offset;
 990       }
 991     }
 992   }
 993 
 994   // Stay out of the way of real safepoints:
 995   void observe_safepoint(JVMState* jvms, int pc_offset) {
 996     if (_pending_jvms != NULL &&
 997         !_pending_jvms->same_calls_as(jvms) &&
 998         _pending_offset < pc_offset) {
 999       emit_non_safepoint();
1000     }
1001     _pending_jvms = NULL;
1002   }
1003 
1004   void flush_at_end() {
1005     if (_pending_jvms != NULL) {
1006       emit_non_safepoint();
1007     }
1008     _pending_jvms = NULL;
1009   }
1010 };
1011 
1012 void NonSafepointEmitter::emit_non_safepoint() {
1013   JVMState* youngest_jvms = _pending_jvms;
1014   int       pc_offset     = _pending_offset;
1015 
1016   // Clear it now:
1017   _pending_jvms = NULL;
1018 
1019   DebugInformationRecorder* debug_info = C->debug_info();
1020   assert(debug_info->recording_non_safepoints(), "sanity");
1021 
1022   debug_info->add_non_safepoint(pc_offset);
1023   int max_depth = youngest_jvms->depth();
1024 
1025   // Visit scopes from oldest to youngest.
1026   for (int depth = 1; depth <= max_depth; depth++) {
1027     JVMState* jvms = youngest_jvms->of_depth(depth);
1028     ciMethod* method = jvms->has_method() ? jvms->method() : NULL;
1029     assert(!jvms->should_reexecute() || depth==max_depth, "reexecute allowed only for the youngest");
1030     debug_info->describe_scope(pc_offset, method, jvms->bci(), jvms->should_reexecute());
1031   }
1032 
1033   // Mark the end of the scope set.
1034   debug_info->end_non_safepoint(pc_offset);
1035 }
1036 
1037 
1038 
1039 // helper for fill_buffer bailout logic
1040 static void turn_off_compiler(Compile* C) {
1041   if (CodeCache::largest_free_block() >= CodeCacheMinimumFreeSpace*10) {
1042     // Do not turn off compilation if a single giant method has
1043     // blown the code cache size.
1044     C->record_failure("excessive request to CodeCache");
1045   } else {
1046     // Let CompilerBroker disable further compilations.
1047     C->record_failure("CodeCache is full");
1048   }
1049 }
1050 
1051 
1052 //------------------------------init_buffer------------------------------------
1053 CodeBuffer* Compile::init_buffer(uint* blk_starts) {
1054 
1055   // Set the initially allocated size
1056   int  code_req   = initial_code_capacity;
1057   int  locs_req   = initial_locs_capacity;
1058   int  stub_req   = TraceJumps ? initial_stub_capacity * 10 : initial_stub_capacity;
1059   int  const_req  = initial_const_capacity;
1060 
1061   int  pad_req    = NativeCall::instruction_size;
1062   // The extra spacing after the code is necessary on some platforms.
1063   // Sometimes we need to patch in a jump after the last instruction,
1064   // if the nmethod has been deoptimized.  (See 4932387, 4894843.)
1065 
1066   // Compute the byte offset where we can store the deopt pc.
1067   if (fixed_slots() != 0) {
1068     _orig_pc_slot_offset_in_bytes = _regalloc->reg2offset(OptoReg::stack2reg(_orig_pc_slot));
1069   }
1070 
1071   // Compute prolog code size
1072   _method_size = 0;
1073   _frame_slots = OptoReg::reg2stack(_matcher->_old_SP)+_regalloc->_framesize;
1074 #ifdef IA64
1075   if (save_argument_registers()) {
1076     // 4815101: this is a stub with implicit and unknown precision fp args.
1077     // The usual spill mechanism can only generate stfd's in this case, which
1078     // doesn't work if the fp reg to spill contains a single-precision denorm.
1079     // Instead, we hack around the normal spill mechanism using stfspill's and
1080     // ldffill's in the MachProlog and MachEpilog emit methods.  We allocate
1081     // space here for the fp arg regs (f8-f15) we're going to thusly spill.
1082     //
1083     // If we ever implement 16-byte 'registers' == stack slots, we can
1084     // get rid of this hack and have SpillCopy generate stfspill/ldffill
1085     // instead of stfd/stfs/ldfd/ldfs.
1086     _frame_slots += 8*(16/BytesPerInt);
1087   }
1088 #endif
1089   assert(_frame_slots >= 0 && _frame_slots < 1000000, "sanity check");
1090 
1091   if (has_mach_constant_base_node()) {
1092     // Fill the constant table.
1093     // Note:  This must happen before shorten_branches.
1094     for (uint i = 0; i < _cfg->_num_blocks; i++) {
1095       Block* b = _cfg->_blocks[i];
1096 
1097       for (uint j = 0; j < b->_nodes.size(); j++) {
1098         Node* n = b->_nodes[j];
1099 
1100         // If the node is a MachConstantNode evaluate the constant
1101         // value section.
1102         if (n->is_MachConstant()) {
1103           MachConstantNode* machcon = n->as_MachConstant();
1104           machcon->eval_constant(C);
1105         }
1106       }
1107     }
1108 
1109     // Calculate the offsets of the constants and the size of the
1110     // constant table (including the padding to the next section).
1111     constant_table().calculate_offsets_and_size();
1112     const_req = constant_table().size();
1113   }
1114 
1115   // Initialize the space for the BufferBlob used to find and verify
1116   // instruction size in MachNode::emit_size()
1117   init_scratch_buffer_blob(const_req);
1118   if (failing())  return NULL; // Out of memory
1119 
1120   // Pre-compute the length of blocks and replace
1121   // long branches with short if machine supports it.
1122   shorten_branches(blk_starts, code_req, locs_req, stub_req);
1123 
1124   // nmethod and CodeBuffer count stubs & constants as part of method's code.
1125   int exception_handler_req = size_exception_handler();
1126   int deopt_handler_req = size_deopt_handler();
1127   exception_handler_req += MAX_stubs_size; // add marginal slop for handler
1128   deopt_handler_req += MAX_stubs_size; // add marginal slop for handler
1129   stub_req += MAX_stubs_size;   // ensure per-stub margin
1130   code_req += MAX_inst_size;    // ensure per-instruction margin
1131 
1132   if (StressCodeBuffers)
1133     code_req = const_req = stub_req = exception_handler_req = deopt_handler_req = 0x10;  // force expansion
1134 
1135   int total_req =
1136     const_req +
1137     code_req +
1138     pad_req +
1139     stub_req +
1140     exception_handler_req +
1141     deopt_handler_req;               // deopt handler
1142 
1143   if (has_method_handle_invokes())
1144     total_req += deopt_handler_req;  // deopt MH handler
1145 
1146   CodeBuffer* cb = code_buffer();
1147   cb->initialize(total_req, locs_req);
1148 
1149   // Have we run out of code space?
1150   if ((cb->blob() == NULL) || (!CompileBroker::should_compile_new_jobs())) {
1151     turn_off_compiler(this);
1152     return NULL;
1153   }
1154   // Configure the code buffer.
1155   cb->initialize_consts_size(const_req);
1156   cb->initialize_stubs_size(stub_req);
1157   cb->initialize_oop_recorder(env()->oop_recorder());
1158 
1159   // fill in the nop array for bundling computations
1160   MachNode *_nop_list[Bundle::_nop_count];
1161   Bundle::initialize_nops(_nop_list, this);
1162 
1163   return cb;
1164 }
1165 
1166 //------------------------------fill_buffer------------------------------------
1167 void Compile::fill_buffer(CodeBuffer* cb, uint* blk_starts) {
1168   // blk_starts[] contains offsets calculated during short branches processing,
1169   // offsets should not be increased during following steps.
1170 
1171   // Compute the size of first NumberOfLoopInstrToAlign instructions at head
1172   // of a loop. It is used to determine the padding for loop alignment.
1173   compute_loop_first_inst_sizes();
1174 
1175   // Create oopmap set.
1176   _oop_map_set = new OopMapSet();
1177 
1178   // !!!!! This preserves old handling of oopmaps for now
1179   debug_info()->set_oopmaps(_oop_map_set);
1180 
1181   uint nblocks  = _cfg->_num_blocks;
1182   // Count and start of implicit null check instructions
1183   uint inct_cnt = 0;
1184   uint *inct_starts = NEW_RESOURCE_ARRAY(uint, nblocks+1);
1185 
1186   // Count and start of calls
1187   uint *call_returns = NEW_RESOURCE_ARRAY(uint, nblocks+1);
1188 
1189   uint  return_offset = 0;
1190   int nop_size = (new (this) MachNopNode())->size(_regalloc);
1191 
1192   int previous_offset = 0;
1193   int current_offset  = 0;
1194   int last_call_offset = -1;
1195   int last_avoid_back_to_back_offset = -1;
1196 #ifdef ASSERT
1197   int block_alignment_padding = 0;
1198 
1199   uint* jmp_target = NEW_RESOURCE_ARRAY(uint,nblocks);
1200   uint* jmp_offset = NEW_RESOURCE_ARRAY(uint,nblocks);
1201   uint* jmp_size   = NEW_RESOURCE_ARRAY(uint,nblocks);
1202   uint* jmp_rule   = NEW_RESOURCE_ARRAY(uint,nblocks);
1203 #endif
1204 
1205   // Create an array of unused labels, one for each basic block, if printing is enabled
1206 #ifndef PRODUCT
1207   int *node_offsets      = NULL;
1208   uint node_offset_limit = unique();
1209 
1210   if (print_assembly())
1211     node_offsets         = NEW_RESOURCE_ARRAY(int, node_offset_limit);
1212 #endif
1213 
1214   NonSafepointEmitter non_safepoints(this);  // emit non-safepoints lazily
1215 
1216   // Emit the constant table.
1217   if (has_mach_constant_base_node()) {
1218     constant_table().emit(*cb);
1219   }
1220 
1221   // Create an array of labels, one for each basic block
1222   Label *blk_labels = NEW_RESOURCE_ARRAY(Label, nblocks+1);
1223   for (uint i=0; i <= nblocks; i++) {
1224     blk_labels[i].init();
1225   }
1226 
1227   // ------------------
1228   // Now fill in the code buffer
1229   Node *delay_slot = NULL;
1230 
1231   for (uint i=0; i < nblocks; i++) {
1232     guarantee(blk_starts[i] >= (uint)cb->insts_size(),"should not increase size");
1233 
1234     Block *b = _cfg->_blocks[i];
1235 
1236     Node *head = b->head();
1237 
1238     // If this block needs to start aligned (i.e, can be reached other
1239     // than by falling-thru from the previous block), then force the
1240     // start of a new bundle.
1241     if (Pipeline::requires_bundling() && starts_bundle(head))
1242       cb->flush_bundle(true);
1243 
1244 #ifdef ASSERT
1245     if (!b->is_connector()) {
1246       stringStream st;
1247       b->dump_head(&_cfg->_bbs, &st);
1248       MacroAssembler(cb).block_comment(st.as_string());
1249     }
1250     jmp_target[i] = 0;
1251     jmp_offset[i] = 0;
1252     jmp_size[i]   = 0;
1253     jmp_rule[i]   = 0;
1254 
1255     // Maximum alignment padding for loop block was used
1256     // during first round of branches shortening, as result
1257     // padding for nodes (sfpt after call) was not added.
1258     // Take this into account for block's size change check
1259     // and allow increase block's size by the difference
1260     // of maximum and actual alignment paddings.
1261     int orig_blk_size = blk_starts[i+1] - blk_starts[i] + block_alignment_padding;
1262 #endif
1263     int blk_offset = current_offset;
1264 
1265     // Define the label at the beginning of the basic block
1266     MacroAssembler(cb).bind(blk_labels[b->_pre_order]);
1267 
1268     uint last_inst = b->_nodes.size();
1269 
1270     // Emit block normally, except for last instruction.
1271     // Emit means "dump code bits into code buffer".
1272     for (uint j = 0; j<last_inst; j++) {
1273 
1274       // Get the node
1275       Node* n = b->_nodes[j];
1276 
1277       // See if delay slots are supported
1278       if (valid_bundle_info(n) &&
1279           node_bundling(n)->used_in_unconditional_delay()) {
1280         assert(delay_slot == NULL, "no use of delay slot node");
1281         assert(n->size(_regalloc) == Pipeline::instr_unit_size(), "delay slot instruction wrong size");
1282 
1283         delay_slot = n;
1284         continue;
1285       }
1286 
1287       // If this starts a new instruction group, then flush the current one
1288       // (but allow split bundles)
1289       if (Pipeline::requires_bundling() && starts_bundle(n))
1290         cb->flush_bundle(false);
1291 
1292       // The following logic is duplicated in the code ifdeffed for
1293       // ENABLE_ZAP_DEAD_LOCALS which appears above in this file.  It
1294       // should be factored out.  Or maybe dispersed to the nodes?
1295 
1296       // Special handling for SafePoint/Call Nodes
1297       bool is_mcall = false;
1298       if (n->is_Mach()) {
1299         MachNode *mach = n->as_Mach();
1300         is_mcall = n->is_MachCall();
1301         bool is_sfn = n->is_MachSafePoint();
1302 
1303         // If this requires all previous instructions be flushed, then do so
1304         if (is_sfn || is_mcall || mach->alignment_required() != 1) {
1305           cb->flush_bundle(true);
1306           current_offset = cb->insts_size();
1307         }
1308 
1309         // A padding may be needed again since a previous instruction
1310         // could be moved to delay slot.
1311 
1312         // align the instruction if necessary
1313         int padding = mach->compute_padding(current_offset);
1314         // Make sure safepoint node for polling is distinct from a call's
1315         // return by adding a nop if needed.
1316         if (is_sfn && !is_mcall && padding == 0 && current_offset == last_call_offset) {
1317           padding = nop_size;
1318         }
1319         if (padding == 0 && mach->avoid_back_to_back() &&
1320             current_offset == last_avoid_back_to_back_offset) {
1321           // Avoid back to back some instructions.
1322           padding = nop_size;
1323         }
1324 
1325         if(padding > 0) {
1326           assert((padding % nop_size) == 0, "padding is not a multiple of NOP size");
1327           int nops_cnt = padding / nop_size;
1328           MachNode *nop = new (this) MachNopNode(nops_cnt);
1329           b->_nodes.insert(j++, nop);
1330           last_inst++;
1331           _cfg->_bbs.map( nop->_idx, b );
1332           nop->emit(*cb, _regalloc);
1333           cb->flush_bundle(true);
1334           current_offset = cb->insts_size();
1335         }
1336 
1337         // Remember the start of the last call in a basic block
1338         if (is_mcall) {
1339           MachCallNode *mcall = mach->as_MachCall();
1340 
1341           // This destination address is NOT PC-relative
1342           mcall->method_set((intptr_t)mcall->entry_point());
1343 
1344           // Save the return address
1345           call_returns[b->_pre_order] = current_offset + mcall->ret_addr_offset();
1346 
1347           if (mcall->is_MachCallLeaf()) {
1348             is_mcall = false;
1349             is_sfn = false;
1350           }
1351         }
1352 
1353         // sfn will be valid whenever mcall is valid now because of inheritance
1354         if (is_sfn || is_mcall) {
1355 
1356           // Handle special safepoint nodes for synchronization
1357           if (!is_mcall) {
1358             MachSafePointNode *sfn = mach->as_MachSafePoint();
1359             // !!!!! Stubs only need an oopmap right now, so bail out
1360             if (sfn->jvms()->method() == NULL) {
1361               // Write the oopmap directly to the code blob??!!
1362 #             ifdef ENABLE_ZAP_DEAD_LOCALS
1363               assert( !is_node_getting_a_safepoint(sfn),  "logic does not match; false positive");
1364 #             endif
1365               continue;
1366             }
1367           } // End synchronization
1368 
1369           non_safepoints.observe_safepoint(mach->as_MachSafePoint()->jvms(),
1370                                            current_offset);
1371           Process_OopMap_Node(mach, current_offset);
1372         } // End if safepoint
1373 
1374         // If this is a null check, then add the start of the previous instruction to the list
1375         else if( mach->is_MachNullCheck() ) {
1376           inct_starts[inct_cnt++] = previous_offset;
1377         }
1378 
1379         // If this is a branch, then fill in the label with the target BB's label
1380         else if (mach->is_MachBranch()) {
1381           // This requires the TRUE branch target be in succs[0]
1382           uint block_num = b->non_connector_successor(0)->_pre_order;
1383 
1384           // Try to replace long branch if delay slot is not used,
1385           // it is mostly for back branches since forward branch's
1386           // distance is not updated yet.
1387           bool delay_slot_is_used = valid_bundle_info(n) &&
1388                                     node_bundling(n)->use_unconditional_delay();
1389           if (!delay_slot_is_used && mach->may_be_short_branch()) {
1390            assert(delay_slot == NULL, "not expecting delay slot node");
1391            int br_size = n->size(_regalloc);
1392             int offset = blk_starts[block_num] - current_offset;
1393             if (block_num >= i) {
1394               // Current and following block's offset are not
1395               // finilized yet, adjust distance by the difference
1396               // between calculated and final offsets of current block.
1397               offset -= (blk_starts[i] - blk_offset);
1398             }
1399             // In the following code a nop could be inserted before
1400             // the branch which will increase the backward distance.
1401             bool needs_padding = (current_offset == last_avoid_back_to_back_offset);
1402             if (needs_padding && offset <= 0)
1403               offset -= nop_size;
1404 
1405             if (_matcher->is_short_branch_offset(mach->rule(), br_size, offset)) {
1406               // We've got a winner.  Replace this branch.
1407               MachNode* replacement = mach->as_MachBranch()->short_branch_version(this);
1408 
1409               // Update the jmp_size.
1410               int new_size = replacement->size(_regalloc);
1411               assert((br_size - new_size) >= (int)nop_size, "short_branch size should be smaller");
1412               // Insert padding between avoid_back_to_back branches.
1413               if (needs_padding && replacement->avoid_back_to_back()) {
1414                 MachNode *nop = new (this) MachNopNode();
1415                 b->_nodes.insert(j++, nop);
1416                 _cfg->_bbs.map(nop->_idx, b);
1417                 last_inst++;
1418                 nop->emit(*cb, _regalloc);
1419                 cb->flush_bundle(true);
1420                 current_offset = cb->insts_size();
1421               }
1422 #ifdef ASSERT
1423               jmp_target[i] = block_num;
1424               jmp_offset[i] = current_offset - blk_offset;
1425               jmp_size[i]   = new_size;
1426               jmp_rule[i]   = mach->rule();
1427 #endif
1428               b->_nodes.map(j, replacement);
1429               mach->subsume_by(replacement);
1430               n    = replacement;
1431               mach = replacement;
1432             }
1433           }
1434           mach->as_MachBranch()->label_set( &blk_labels[block_num], block_num );
1435         } else if (mach->ideal_Opcode() == Op_Jump) {
1436           for (uint h = 0; h < b->_num_succs; h++) {
1437             Block* succs_block = b->_succs[h];
1438             for (uint j = 1; j < succs_block->num_preds(); j++) {
1439               Node* jpn = succs_block->pred(j);
1440               if (jpn->is_JumpProj() && jpn->in(0) == mach) {
1441                 uint block_num = succs_block->non_connector()->_pre_order;
1442                 Label *blkLabel = &blk_labels[block_num];
1443                 mach->add_case_label(jpn->as_JumpProj()->proj_no(), blkLabel);
1444               }
1445             }
1446           }
1447         }
1448 
1449 #ifdef ASSERT
1450         // Check that oop-store precedes the card-mark
1451         else if (mach->ideal_Opcode() == Op_StoreCM) {
1452           uint storeCM_idx = j;
1453           int count = 0;
1454           for (uint prec = mach->req(); prec < mach->len(); prec++) {
1455             Node *oop_store = mach->in(prec);  // Precedence edge
1456             if (oop_store == NULL) continue;
1457             count++;
1458             uint i4;
1459             for( i4 = 0; i4 < last_inst; ++i4 ) {
1460               if( b->_nodes[i4] == oop_store ) break;
1461             }
1462             // Note: This test can provide a false failure if other precedence
1463             // edges have been added to the storeCMNode.
1464             assert( i4 == last_inst || i4 < storeCM_idx, "CM card-mark executes before oop-store");
1465           }
1466           assert(count > 0, "storeCM expects at least one precedence edge");
1467         }
1468 #endif
1469 
1470         else if (!n->is_Proj()) {
1471           // Remember the beginning of the previous instruction, in case
1472           // it's followed by a flag-kill and a null-check.  Happens on
1473           // Intel all the time, with add-to-memory kind of opcodes.
1474           previous_offset = current_offset;
1475         }
1476       }
1477 
1478       // Verify that there is sufficient space remaining
1479       cb->insts()->maybe_expand_to_ensure_remaining(MAX_inst_size);
1480       if ((cb->blob() == NULL) || (!CompileBroker::should_compile_new_jobs())) {
1481         turn_off_compiler(this);
1482         return;
1483       }
1484 
1485       // Save the offset for the listing
1486 #ifndef PRODUCT
1487       if (node_offsets && n->_idx < node_offset_limit)
1488         node_offsets[n->_idx] = cb->insts_size();
1489 #endif
1490 
1491       // "Normal" instruction case
1492       DEBUG_ONLY( uint instr_offset = cb->insts_size(); )
1493       n->emit(*cb, _regalloc);
1494       current_offset  = cb->insts_size();
1495 
1496 #ifdef ASSERT
1497       if (n->size(_regalloc) < (current_offset-instr_offset)) {
1498         n->dump();
1499         assert(false, "wrong size of mach node");
1500       }
1501 #endif
1502       non_safepoints.observe_instruction(n, current_offset);
1503 
1504       // mcall is last "call" that can be a safepoint
1505       // record it so we can see if a poll will directly follow it
1506       // in which case we'll need a pad to make the PcDesc sites unique
1507       // see  5010568. This can be slightly inaccurate but conservative
1508       // in the case that return address is not actually at current_offset.
1509       // This is a small price to pay.
1510 
1511       if (is_mcall) {
1512         last_call_offset = current_offset;
1513       }
1514 
1515       if (n->is_Mach() && n->as_Mach()->avoid_back_to_back()) {
1516         // Avoid back to back some instructions.
1517         last_avoid_back_to_back_offset = current_offset;
1518       }
1519 
1520       // See if this instruction has a delay slot
1521       if (valid_bundle_info(n) && node_bundling(n)->use_unconditional_delay()) {
1522         assert(delay_slot != NULL, "expecting delay slot node");
1523 
1524         // Back up 1 instruction
1525         cb->set_insts_end(cb->insts_end() - Pipeline::instr_unit_size());
1526 
1527         // Save the offset for the listing
1528 #ifndef PRODUCT
1529         if (node_offsets && delay_slot->_idx < node_offset_limit)
1530           node_offsets[delay_slot->_idx] = cb->insts_size();
1531 #endif
1532 
1533         // Support a SafePoint in the delay slot
1534         if (delay_slot->is_MachSafePoint()) {
1535           MachNode *mach = delay_slot->as_Mach();
1536           // !!!!! Stubs only need an oopmap right now, so bail out
1537           if (!mach->is_MachCall() && mach->as_MachSafePoint()->jvms()->method() == NULL) {
1538             // Write the oopmap directly to the code blob??!!
1539 #           ifdef ENABLE_ZAP_DEAD_LOCALS
1540             assert( !is_node_getting_a_safepoint(mach),  "logic does not match; false positive");
1541 #           endif
1542             delay_slot = NULL;
1543             continue;
1544           }
1545 
1546           int adjusted_offset = current_offset - Pipeline::instr_unit_size();
1547           non_safepoints.observe_safepoint(mach->as_MachSafePoint()->jvms(),
1548                                            adjusted_offset);
1549           // Generate an OopMap entry
1550           Process_OopMap_Node(mach, adjusted_offset);
1551         }
1552 
1553         // Insert the delay slot instruction
1554         delay_slot->emit(*cb, _regalloc);
1555 
1556         // Don't reuse it
1557         delay_slot = NULL;
1558       }
1559 
1560     } // End for all instructions in block
1561     assert((uint)blk_offset <= blk_starts[i], "shouldn't increase distance");
1562     blk_starts[i] = blk_offset;
1563 
1564     // If the next block is the top of a loop, pad this block out to align
1565     // the loop top a little. Helps prevent pipe stalls at loop back branches.
1566     if (i < nblocks-1) {
1567       Block *nb = _cfg->_blocks[i+1];
1568       int padding = nb->alignment_padding(current_offset);
1569       if( padding > 0 ) {
1570         MachNode *nop = new (this) MachNopNode(padding / nop_size);
1571         b->_nodes.insert( b->_nodes.size(), nop );
1572         _cfg->_bbs.map( nop->_idx, b );
1573         nop->emit(*cb, _regalloc);
1574         current_offset = cb->insts_size();
1575       }
1576 #ifdef ASSERT
1577       int max_loop_pad = nb->code_alignment()-relocInfo::addr_unit();
1578       block_alignment_padding = (max_loop_pad - padding);
1579       assert(block_alignment_padding >= 0, "sanity");
1580 #endif
1581     }
1582     // Verify that the distance for generated before forward
1583     // short branches is still valid.
1584     assert(orig_blk_size >= (current_offset - blk_offset), "shouldn't increase block size");
1585 
1586   } // End of for all blocks
1587   blk_starts[nblocks] = current_offset;
1588 
1589   non_safepoints.flush_at_end();
1590 
1591   // Offset too large?
1592   if (failing())  return;
1593 
1594   // Define a pseudo-label at the end of the code
1595   MacroAssembler(cb).bind( blk_labels[nblocks] );
1596 
1597   // Compute the size of the first block
1598   _first_block_size = blk_labels[1].loc_pos() - blk_labels[0].loc_pos();
1599 
1600   assert(cb->insts_size() < 500000, "method is unreasonably large");
1601 
1602 #ifdef ASSERT
1603   for (uint i = 0; i < nblocks; i++) { // For all blocks
1604     if (jmp_target[i] != 0) {
1605       int br_size = jmp_size[i];
1606       int offset = blk_starts[jmp_target[i]]-(blk_starts[i] + jmp_offset[i]);
1607       if (!_matcher->is_short_branch_offset(jmp_rule[i], br_size, offset)) {
1608         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]);
1609         assert(false, "Displacement too large for short jmp");
1610       }
1611     }
1612   }
1613 #endif
1614 
1615   // ------------------
1616 
1617 #ifndef PRODUCT
1618   // Information on the size of the method, without the extraneous code
1619   Scheduling::increment_method_size(cb->insts_size());
1620 #endif
1621 
1622   // ------------------
1623   // Fill in exception table entries.
1624   FillExceptionTables(inct_cnt, call_returns, inct_starts, blk_labels);
1625 
1626   // Only java methods have exception handlers and deopt handlers
1627   if (_method) {
1628     // Emit the exception handler code.
1629     _code_offsets.set_value(CodeOffsets::Exceptions, emit_exception_handler(*cb));
1630     // Emit the deopt handler code.
1631     _code_offsets.set_value(CodeOffsets::Deopt, emit_deopt_handler(*cb));
1632 
1633     // Emit the MethodHandle deopt handler code (if required).
1634     if (has_method_handle_invokes()) {
1635       // We can use the same code as for the normal deopt handler, we
1636       // just need a different entry point address.
1637       _code_offsets.set_value(CodeOffsets::DeoptMH, emit_deopt_handler(*cb));
1638     }
1639   }
1640 
1641   // One last check for failed CodeBuffer::expand:
1642   if ((cb->blob() == NULL) || (!CompileBroker::should_compile_new_jobs())) {
1643     turn_off_compiler(this);
1644     return;
1645   }
1646 
1647 #ifndef PRODUCT
1648   // Dump the assembly code, including basic-block numbers
1649   if (print_assembly()) {
1650     ttyLocker ttyl;  // keep the following output all in one block
1651     if (!VMThread::should_terminate()) {  // test this under the tty lock
1652       // This output goes directly to the tty, not the compiler log.
1653       // To enable tools to match it up with the compilation activity,
1654       // be sure to tag this tty output with the compile ID.
1655       if (xtty != NULL) {
1656         xtty->head("opto_assembly compile_id='%d'%s", compile_id(),
1657                    is_osr_compilation()    ? " compile_kind='osr'" :
1658                    "");
1659       }
1660       if (method() != NULL) {
1661         method()->print_oop();
1662         print_codes();
1663       }
1664       dump_asm(node_offsets, node_offset_limit);
1665       if (xtty != NULL) {
1666         xtty->tail("opto_assembly");
1667       }
1668     }
1669   }
1670 #endif
1671 
1672 }
1673 
1674 void Compile::FillExceptionTables(uint cnt, uint *call_returns, uint *inct_starts, Label *blk_labels) {
1675   _inc_table.set_size(cnt);
1676 
1677   uint inct_cnt = 0;
1678   for( uint i=0; i<_cfg->_num_blocks; i++ ) {
1679     Block *b = _cfg->_blocks[i];
1680     Node *n = NULL;
1681     int j;
1682 
1683     // Find the branch; ignore trailing NOPs.
1684     for( j = b->_nodes.size()-1; j>=0; j-- ) {
1685       n = b->_nodes[j];
1686       if( !n->is_Mach() || n->as_Mach()->ideal_Opcode() != Op_Con )
1687         break;
1688     }
1689 
1690     // If we didn't find anything, continue
1691     if( j < 0 ) continue;
1692 
1693     // Compute ExceptionHandlerTable subtable entry and add it
1694     // (skip empty blocks)
1695     if( n->is_Catch() ) {
1696 
1697       // Get the offset of the return from the call
1698       uint call_return = call_returns[b->_pre_order];
1699 #ifdef ASSERT
1700       assert( call_return > 0, "no call seen for this basic block" );
1701       while( b->_nodes[--j]->is_MachProj() ) ;
1702       assert( b->_nodes[j]->is_MachCall(), "CatchProj must follow call" );
1703 #endif
1704       // last instruction is a CatchNode, find it's CatchProjNodes
1705       int nof_succs = b->_num_succs;
1706       // allocate space
1707       GrowableArray<intptr_t> handler_bcis(nof_succs);
1708       GrowableArray<intptr_t> handler_pcos(nof_succs);
1709       // iterate through all successors
1710       for (int j = 0; j < nof_succs; j++) {
1711         Block* s = b->_succs[j];
1712         bool found_p = false;
1713         for( uint k = 1; k < s->num_preds(); k++ ) {
1714           Node *pk = s->pred(k);
1715           if( pk->is_CatchProj() && pk->in(0) == n ) {
1716             const CatchProjNode* p = pk->as_CatchProj();
1717             found_p = true;
1718             // add the corresponding handler bci & pco information
1719             if( p->_con != CatchProjNode::fall_through_index ) {
1720               // p leads to an exception handler (and is not fall through)
1721               assert(s == _cfg->_blocks[s->_pre_order],"bad numbering");
1722               // no duplicates, please
1723               if( !handler_bcis.contains(p->handler_bci()) ) {
1724                 uint block_num = s->non_connector()->_pre_order;
1725                 handler_bcis.append(p->handler_bci());
1726                 handler_pcos.append(blk_labels[block_num].loc_pos());
1727               }
1728             }
1729           }
1730         }
1731         assert(found_p, "no matching predecessor found");
1732         // Note:  Due to empty block removal, one block may have
1733         // several CatchProj inputs, from the same Catch.
1734       }
1735 
1736       // Set the offset of the return from the call
1737       _handler_table.add_subtable(call_return, &handler_bcis, NULL, &handler_pcos);
1738       continue;
1739     }
1740 
1741     // Handle implicit null exception table updates
1742     if( n->is_MachNullCheck() ) {
1743       uint block_num = b->non_connector_successor(0)->_pre_order;
1744       _inc_table.append( inct_starts[inct_cnt++], blk_labels[block_num].loc_pos() );
1745       continue;
1746     }
1747   } // End of for all blocks fill in exception table entries
1748 }
1749 
1750 // Static Variables
1751 #ifndef PRODUCT
1752 uint Scheduling::_total_nop_size = 0;
1753 uint Scheduling::_total_method_size = 0;
1754 uint Scheduling::_total_branches = 0;
1755 uint Scheduling::_total_unconditional_delays = 0;
1756 uint Scheduling::_total_instructions_per_bundle[Pipeline::_max_instrs_per_cycle+1];
1757 #endif
1758 
1759 // Initializer for class Scheduling
1760 
1761 Scheduling::Scheduling(Arena *arena, Compile &compile)
1762   : _arena(arena),
1763     _cfg(compile.cfg()),
1764     _bbs(compile.cfg()->_bbs),
1765     _regalloc(compile.regalloc()),
1766     _reg_node(arena),
1767     _bundle_instr_count(0),
1768     _bundle_cycle_number(0),
1769     _scheduled(arena),
1770     _available(arena),
1771     _next_node(NULL),
1772     _bundle_use(0, 0, resource_count, &_bundle_use_elements[0]),
1773     _pinch_free_list(arena)
1774 #ifndef PRODUCT
1775   , _branches(0)
1776   , _unconditional_delays(0)
1777 #endif
1778 {
1779   // Create a MachNopNode
1780   _nop = new (&compile) MachNopNode();
1781 
1782   // Now that the nops are in the array, save the count
1783   // (but allow entries for the nops)
1784   _node_bundling_limit = compile.unique();
1785   uint node_max = _regalloc->node_regs_max_index();
1786 
1787   compile.set_node_bundling_limit(_node_bundling_limit);
1788 
1789   // This one is persistent within the Compile class
1790   _node_bundling_base = NEW_ARENA_ARRAY(compile.comp_arena(), Bundle, node_max);
1791 
1792   // Allocate space for fixed-size arrays
1793   _node_latency    = NEW_ARENA_ARRAY(arena, unsigned short, node_max);
1794   _uses            = NEW_ARENA_ARRAY(arena, short,          node_max);
1795   _current_latency = NEW_ARENA_ARRAY(arena, unsigned short, node_max);
1796 
1797   // Clear the arrays
1798   memset(_node_bundling_base, 0, node_max * sizeof(Bundle));
1799   memset(_node_latency,       0, node_max * sizeof(unsigned short));
1800   memset(_uses,               0, node_max * sizeof(short));
1801   memset(_current_latency,    0, node_max * sizeof(unsigned short));
1802 
1803   // Clear the bundling information
1804   memcpy(_bundle_use_elements,
1805     Pipeline_Use::elaborated_elements,
1806     sizeof(Pipeline_Use::elaborated_elements));
1807 
1808   // Get the last node
1809   Block *bb = _cfg->_blocks[_cfg->_blocks.size()-1];
1810 
1811   _next_node = bb->_nodes[bb->_nodes.size()-1];
1812 }
1813 
1814 #ifndef PRODUCT
1815 // Scheduling destructor
1816 Scheduling::~Scheduling() {
1817   _total_branches             += _branches;
1818   _total_unconditional_delays += _unconditional_delays;
1819 }
1820 #endif
1821 
1822 // Step ahead "i" cycles
1823 void Scheduling::step(uint i) {
1824 
1825   Bundle *bundle = node_bundling(_next_node);
1826   bundle->set_starts_bundle();
1827 
1828   // Update the bundle record, but leave the flags information alone
1829   if (_bundle_instr_count > 0) {
1830     bundle->set_instr_count(_bundle_instr_count);
1831     bundle->set_resources_used(_bundle_use.resourcesUsed());
1832   }
1833 
1834   // Update the state information
1835   _bundle_instr_count = 0;
1836   _bundle_cycle_number += i;
1837   _bundle_use.step(i);
1838 }
1839 
1840 void Scheduling::step_and_clear() {
1841   Bundle *bundle = node_bundling(_next_node);
1842   bundle->set_starts_bundle();
1843 
1844   // Update the bundle record
1845   if (_bundle_instr_count > 0) {
1846     bundle->set_instr_count(_bundle_instr_count);
1847     bundle->set_resources_used(_bundle_use.resourcesUsed());
1848 
1849     _bundle_cycle_number += 1;
1850   }
1851 
1852   // Clear the bundling information
1853   _bundle_instr_count = 0;
1854   _bundle_use.reset();
1855 
1856   memcpy(_bundle_use_elements,
1857     Pipeline_Use::elaborated_elements,
1858     sizeof(Pipeline_Use::elaborated_elements));
1859 }
1860 
1861 //------------------------------ScheduleAndBundle------------------------------
1862 // Perform instruction scheduling and bundling over the sequence of
1863 // instructions in backwards order.
1864 void Compile::ScheduleAndBundle() {
1865 
1866   // Don't optimize this if it isn't a method
1867   if (!_method)
1868     return;
1869 
1870   // Don't optimize this if scheduling is disabled
1871   if (!do_scheduling())
1872     return;
1873 
1874   NOT_PRODUCT( TracePhase t2("isched", &_t_instrSched, TimeCompiler); )
1875 
1876   // Create a data structure for all the scheduling information
1877   Scheduling scheduling(Thread::current()->resource_area(), *this);
1878 
1879   // Walk backwards over each basic block, computing the needed alignment
1880   // Walk over all the basic blocks
1881   scheduling.DoScheduling();
1882 }
1883 
1884 //------------------------------ComputeLocalLatenciesForward-------------------
1885 // Compute the latency of all the instructions.  This is fairly simple,
1886 // because we already have a legal ordering.  Walk over the instructions
1887 // from first to last, and compute the latency of the instruction based
1888 // on the latency of the preceding instruction(s).
1889 void Scheduling::ComputeLocalLatenciesForward(const Block *bb) {
1890 #ifndef PRODUCT
1891   if (_cfg->C->trace_opto_output())
1892     tty->print("# -> ComputeLocalLatenciesForward\n");
1893 #endif
1894 
1895   // Walk over all the schedulable instructions
1896   for( uint j=_bb_start; j < _bb_end; j++ ) {
1897 
1898     // This is a kludge, forcing all latency calculations to start at 1.
1899     // Used to allow latency 0 to force an instruction to the beginning
1900     // of the bb
1901     uint latency = 1;
1902     Node *use = bb->_nodes[j];
1903     uint nlen = use->len();
1904 
1905     // Walk over all the inputs
1906     for ( uint k=0; k < nlen; k++ ) {
1907       Node *def = use->in(k);
1908       if (!def)
1909         continue;
1910 
1911       uint l = _node_latency[def->_idx] + use->latency(k);
1912       if (latency < l)
1913         latency = l;
1914     }
1915 
1916     _node_latency[use->_idx] = latency;
1917 
1918 #ifndef PRODUCT
1919     if (_cfg->C->trace_opto_output()) {
1920       tty->print("# latency %4d: ", latency);
1921       use->dump();
1922     }
1923 #endif
1924   }
1925 
1926 #ifndef PRODUCT
1927   if (_cfg->C->trace_opto_output())
1928     tty->print("# <- ComputeLocalLatenciesForward\n");
1929 #endif
1930 
1931 } // end ComputeLocalLatenciesForward
1932 
1933 // See if this node fits into the present instruction bundle
1934 bool Scheduling::NodeFitsInBundle(Node *n) {
1935   uint n_idx = n->_idx;
1936 
1937   // If this is the unconditional delay instruction, then it fits
1938   if (n == _unconditional_delay_slot) {
1939 #ifndef PRODUCT
1940     if (_cfg->C->trace_opto_output())
1941       tty->print("#     NodeFitsInBundle [%4d]: TRUE; is in unconditional delay slot\n", n->_idx);
1942 #endif
1943     return (true);
1944   }
1945 
1946   // If the node cannot be scheduled this cycle, skip it
1947   if (_current_latency[n_idx] > _bundle_cycle_number) {
1948 #ifndef PRODUCT
1949     if (_cfg->C->trace_opto_output())
1950       tty->print("#     NodeFitsInBundle [%4d]: FALSE; latency %4d > %d\n",
1951         n->_idx, _current_latency[n_idx], _bundle_cycle_number);
1952 #endif
1953     return (false);
1954   }
1955 
1956   const Pipeline *node_pipeline = n->pipeline();
1957 
1958   uint instruction_count = node_pipeline->instructionCount();
1959   if (node_pipeline->mayHaveNoCode() && n->size(_regalloc) == 0)
1960     instruction_count = 0;
1961   else if (node_pipeline->hasBranchDelay() && !_unconditional_delay_slot)
1962     instruction_count++;
1963 
1964   if (_bundle_instr_count + instruction_count > Pipeline::_max_instrs_per_cycle) {
1965 #ifndef PRODUCT
1966     if (_cfg->C->trace_opto_output())
1967       tty->print("#     NodeFitsInBundle [%4d]: FALSE; too many instructions: %d > %d\n",
1968         n->_idx, _bundle_instr_count + instruction_count, Pipeline::_max_instrs_per_cycle);
1969 #endif
1970     return (false);
1971   }
1972 
1973   // Don't allow non-machine nodes to be handled this way
1974   if (!n->is_Mach() && instruction_count == 0)
1975     return (false);
1976 
1977   // See if there is any overlap
1978   uint delay = _bundle_use.full_latency(0, node_pipeline->resourceUse());
1979 
1980   if (delay > 0) {
1981 #ifndef PRODUCT
1982     if (_cfg->C->trace_opto_output())
1983       tty->print("#     NodeFitsInBundle [%4d]: FALSE; functional units overlap\n", n_idx);
1984 #endif
1985     return false;
1986   }
1987 
1988 #ifndef PRODUCT
1989   if (_cfg->C->trace_opto_output())
1990     tty->print("#     NodeFitsInBundle [%4d]:  TRUE\n", n_idx);
1991 #endif
1992 
1993   return true;
1994 }
1995 
1996 Node * Scheduling::ChooseNodeToBundle() {
1997   uint siz = _available.size();
1998 
1999   if (siz == 0) {
2000 
2001 #ifndef PRODUCT
2002     if (_cfg->C->trace_opto_output())
2003       tty->print("#   ChooseNodeToBundle: NULL\n");
2004 #endif
2005     return (NULL);
2006   }
2007 
2008   // Fast path, if only 1 instruction in the bundle
2009   if (siz == 1) {
2010 #ifndef PRODUCT
2011     if (_cfg->C->trace_opto_output()) {
2012       tty->print("#   ChooseNodeToBundle (only 1): ");
2013       _available[0]->dump();
2014     }
2015 #endif
2016     return (_available[0]);
2017   }
2018 
2019   // Don't bother, if the bundle is already full
2020   if (_bundle_instr_count < Pipeline::_max_instrs_per_cycle) {
2021     for ( uint i = 0; i < siz; i++ ) {
2022       Node *n = _available[i];
2023 
2024       // Skip projections, we'll handle them another way
2025       if (n->is_Proj())
2026         continue;
2027 
2028       // This presupposed that instructions are inserted into the
2029       // available list in a legality order; i.e. instructions that
2030       // must be inserted first are at the head of the list
2031       if (NodeFitsInBundle(n)) {
2032 #ifndef PRODUCT
2033         if (_cfg->C->trace_opto_output()) {
2034           tty->print("#   ChooseNodeToBundle: ");
2035           n->dump();
2036         }
2037 #endif
2038         return (n);
2039       }
2040     }
2041   }
2042 
2043   // Nothing fits in this bundle, choose the highest priority
2044 #ifndef PRODUCT
2045   if (_cfg->C->trace_opto_output()) {
2046     tty->print("#   ChooseNodeToBundle: ");
2047     _available[0]->dump();
2048   }
2049 #endif
2050 
2051   return _available[0];
2052 }
2053 
2054 //------------------------------AddNodeToAvailableList-------------------------
2055 void Scheduling::AddNodeToAvailableList(Node *n) {
2056   assert( !n->is_Proj(), "projections never directly made available" );
2057 #ifndef PRODUCT
2058   if (_cfg->C->trace_opto_output()) {
2059     tty->print("#   AddNodeToAvailableList: ");
2060     n->dump();
2061   }
2062 #endif
2063 
2064   int latency = _current_latency[n->_idx];
2065 
2066   // Insert in latency order (insertion sort)
2067   uint i;
2068   for ( i=0; i < _available.size(); i++ )
2069     if (_current_latency[_available[i]->_idx] > latency)
2070       break;
2071 
2072   // Special Check for compares following branches
2073   if( n->is_Mach() && _scheduled.size() > 0 ) {
2074     int op = n->as_Mach()->ideal_Opcode();
2075     Node *last = _scheduled[0];
2076     if( last->is_MachIf() && last->in(1) == n &&
2077         ( op == Op_CmpI ||
2078           op == Op_CmpU ||
2079           op == Op_CmpP ||
2080           op == Op_CmpF ||
2081           op == Op_CmpD ||
2082           op == Op_CmpL ) ) {
2083 
2084       // Recalculate position, moving to front of same latency
2085       for ( i=0 ; i < _available.size(); i++ )
2086         if (_current_latency[_available[i]->_idx] >= latency)
2087           break;
2088     }
2089   }
2090 
2091   // Insert the node in the available list
2092   _available.insert(i, n);
2093 
2094 #ifndef PRODUCT
2095   if (_cfg->C->trace_opto_output())
2096     dump_available();
2097 #endif
2098 }
2099 
2100 //------------------------------DecrementUseCounts-----------------------------
2101 void Scheduling::DecrementUseCounts(Node *n, const Block *bb) {
2102   for ( uint i=0; i < n->len(); i++ ) {
2103     Node *def = n->in(i);
2104     if (!def) continue;
2105     if( def->is_Proj() )        // If this is a machine projection, then
2106       def = def->in(0);         // propagate usage thru to the base instruction
2107 
2108     if( _bbs[def->_idx] != bb ) // Ignore if not block-local
2109       continue;
2110 
2111     // Compute the latency
2112     uint l = _bundle_cycle_number + n->latency(i);
2113     if (_current_latency[def->_idx] < l)
2114       _current_latency[def->_idx] = l;
2115 
2116     // If this does not have uses then schedule it
2117     if ((--_uses[def->_idx]) == 0)
2118       AddNodeToAvailableList(def);
2119   }
2120 }
2121 
2122 //------------------------------AddNodeToBundle--------------------------------
2123 void Scheduling::AddNodeToBundle(Node *n, const Block *bb) {
2124 #ifndef PRODUCT
2125   if (_cfg->C->trace_opto_output()) {
2126     tty->print("#   AddNodeToBundle: ");
2127     n->dump();
2128   }
2129 #endif
2130 
2131   // Remove this from the available list
2132   uint i;
2133   for (i = 0; i < _available.size(); i++)
2134     if (_available[i] == n)
2135       break;
2136   assert(i < _available.size(), "entry in _available list not found");
2137   _available.remove(i);
2138 
2139   // See if this fits in the current bundle
2140   const Pipeline *node_pipeline = n->pipeline();
2141   const Pipeline_Use& node_usage = node_pipeline->resourceUse();
2142 
2143   // Check for instructions to be placed in the delay slot. We
2144   // do this before we actually schedule the current instruction,
2145   // because the delay slot follows the current instruction.
2146   if (Pipeline::_branch_has_delay_slot &&
2147       node_pipeline->hasBranchDelay() &&
2148       !_unconditional_delay_slot) {
2149 
2150     uint siz = _available.size();
2151 
2152     // Conditional branches can support an instruction that
2153     // is unconditionally executed and not dependent by the
2154     // branch, OR a conditionally executed instruction if
2155     // the branch is taken.  In practice, this means that
2156     // the first instruction at the branch target is
2157     // copied to the delay slot, and the branch goes to
2158     // the instruction after that at the branch target
2159     if ( n->is_MachBranch() ) {
2160 
2161       assert( !n->is_MachNullCheck(), "should not look for delay slot for Null Check" );
2162       assert( !n->is_Catch(),         "should not look for delay slot for Catch" );
2163 
2164 #ifndef PRODUCT
2165       _branches++;
2166 #endif
2167 
2168       // At least 1 instruction is on the available list
2169       // that is not dependent on the branch
2170       for (uint i = 0; i < siz; i++) {
2171         Node *d = _available[i];
2172         const Pipeline *avail_pipeline = d->pipeline();
2173 
2174         // Don't allow safepoints in the branch shadow, that will
2175         // cause a number of difficulties
2176         if ( avail_pipeline->instructionCount() == 1 &&
2177             !avail_pipeline->hasMultipleBundles() &&
2178             !avail_pipeline->hasBranchDelay() &&
2179             Pipeline::instr_has_unit_size() &&
2180             d->size(_regalloc) == Pipeline::instr_unit_size() &&
2181             NodeFitsInBundle(d) &&
2182             !node_bundling(d)->used_in_delay()) {
2183 
2184           if (d->is_Mach() && !d->is_MachSafePoint()) {
2185             // A node that fits in the delay slot was found, so we need to
2186             // set the appropriate bits in the bundle pipeline information so
2187             // that it correctly indicates resource usage.  Later, when we
2188             // attempt to add this instruction to the bundle, we will skip
2189             // setting the resource usage.
2190             _unconditional_delay_slot = d;
2191             node_bundling(n)->set_use_unconditional_delay();
2192             node_bundling(d)->set_used_in_unconditional_delay();
2193             _bundle_use.add_usage(avail_pipeline->resourceUse());
2194             _current_latency[d->_idx] = _bundle_cycle_number;
2195             _next_node = d;
2196             ++_bundle_instr_count;
2197 #ifndef PRODUCT
2198             _unconditional_delays++;
2199 #endif
2200             break;
2201           }
2202         }
2203       }
2204     }
2205 
2206     // No delay slot, add a nop to the usage
2207     if (!_unconditional_delay_slot) {
2208       // See if adding an instruction in the delay slot will overflow
2209       // the bundle.
2210       if (!NodeFitsInBundle(_nop)) {
2211 #ifndef PRODUCT
2212         if (_cfg->C->trace_opto_output())
2213           tty->print("#  *** STEP(1 instruction for delay slot) ***\n");
2214 #endif
2215         step(1);
2216       }
2217 
2218       _bundle_use.add_usage(_nop->pipeline()->resourceUse());
2219       _next_node = _nop;
2220       ++_bundle_instr_count;
2221     }
2222 
2223     // See if the instruction in the delay slot requires a
2224     // step of the bundles
2225     if (!NodeFitsInBundle(n)) {
2226 #ifndef PRODUCT
2227         if (_cfg->C->trace_opto_output())
2228           tty->print("#  *** STEP(branch won't fit) ***\n");
2229 #endif
2230         // Update the state information
2231         _bundle_instr_count = 0;
2232         _bundle_cycle_number += 1;
2233         _bundle_use.step(1);
2234     }
2235   }
2236 
2237   // Get the number of instructions
2238   uint instruction_count = node_pipeline->instructionCount();
2239   if (node_pipeline->mayHaveNoCode() && n->size(_regalloc) == 0)
2240     instruction_count = 0;
2241 
2242   // Compute the latency information
2243   uint delay = 0;
2244 
2245   if (instruction_count > 0 || !node_pipeline->mayHaveNoCode()) {
2246     int relative_latency = _current_latency[n->_idx] - _bundle_cycle_number;
2247     if (relative_latency < 0)
2248       relative_latency = 0;
2249 
2250     delay = _bundle_use.full_latency(relative_latency, node_usage);
2251 
2252     // Does not fit in this bundle, start a new one
2253     if (delay > 0) {
2254       step(delay);
2255 
2256 #ifndef PRODUCT
2257       if (_cfg->C->trace_opto_output())
2258         tty->print("#  *** STEP(%d) ***\n", delay);
2259 #endif
2260     }
2261   }
2262 
2263   // If this was placed in the delay slot, ignore it
2264   if (n != _unconditional_delay_slot) {
2265 
2266     if (delay == 0) {
2267       if (node_pipeline->hasMultipleBundles()) {
2268 #ifndef PRODUCT
2269         if (_cfg->C->trace_opto_output())
2270           tty->print("#  *** STEP(multiple instructions) ***\n");
2271 #endif
2272         step(1);
2273       }
2274 
2275       else if (instruction_count + _bundle_instr_count > Pipeline::_max_instrs_per_cycle) {
2276 #ifndef PRODUCT
2277         if (_cfg->C->trace_opto_output())
2278           tty->print("#  *** STEP(%d >= %d instructions) ***\n",
2279             instruction_count + _bundle_instr_count,
2280             Pipeline::_max_instrs_per_cycle);
2281 #endif
2282         step(1);
2283       }
2284     }
2285 
2286     if (node_pipeline->hasBranchDelay() && !_unconditional_delay_slot)
2287       _bundle_instr_count++;
2288 
2289     // Set the node's latency
2290     _current_latency[n->_idx] = _bundle_cycle_number;
2291 
2292     // Now merge the functional unit information
2293     if (instruction_count > 0 || !node_pipeline->mayHaveNoCode())
2294       _bundle_use.add_usage(node_usage);
2295 
2296     // Increment the number of instructions in this bundle
2297     _bundle_instr_count += instruction_count;
2298 
2299     // Remember this node for later
2300     if (n->is_Mach())
2301       _next_node = n;
2302   }
2303 
2304   // It's possible to have a BoxLock in the graph and in the _bbs mapping but
2305   // not in the bb->_nodes array.  This happens for debug-info-only BoxLocks.
2306   // 'Schedule' them (basically ignore in the schedule) but do not insert them
2307   // into the block.  All other scheduled nodes get put in the schedule here.
2308   int op = n->Opcode();
2309   if( (op == Op_Node && n->req() == 0) || // anti-dependence node OR
2310       (op != Op_Node &&         // Not an unused antidepedence node and
2311        // not an unallocated boxlock
2312        (OptoReg::is_valid(_regalloc->get_reg_first(n)) || op != Op_BoxLock)) ) {
2313 
2314     // Push any trailing projections
2315     if( bb->_nodes[bb->_nodes.size()-1] != n ) {
2316       for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2317         Node *foi = n->fast_out(i);
2318         if( foi->is_Proj() )
2319           _scheduled.push(foi);
2320       }
2321     }
2322 
2323     // Put the instruction in the schedule list
2324     _scheduled.push(n);
2325   }
2326 
2327 #ifndef PRODUCT
2328   if (_cfg->C->trace_opto_output())
2329     dump_available();
2330 #endif
2331 
2332   // Walk all the definitions, decrementing use counts, and
2333   // if a definition has a 0 use count, place it in the available list.
2334   DecrementUseCounts(n,bb);
2335 }
2336 
2337 //------------------------------ComputeUseCount--------------------------------
2338 // This method sets the use count within a basic block.  We will ignore all
2339 // uses outside the current basic block.  As we are doing a backwards walk,
2340 // any node we reach that has a use count of 0 may be scheduled.  This also
2341 // avoids the problem of cyclic references from phi nodes, as long as phi
2342 // nodes are at the front of the basic block.  This method also initializes
2343 // the available list to the set of instructions that have no uses within this
2344 // basic block.
2345 void Scheduling::ComputeUseCount(const Block *bb) {
2346 #ifndef PRODUCT
2347   if (_cfg->C->trace_opto_output())
2348     tty->print("# -> ComputeUseCount\n");
2349 #endif
2350 
2351   // Clear the list of available and scheduled instructions, just in case
2352   _available.clear();
2353   _scheduled.clear();
2354 
2355   // No delay slot specified
2356   _unconditional_delay_slot = NULL;
2357 
2358 #ifdef ASSERT
2359   for( uint i=0; i < bb->_nodes.size(); i++ )
2360     assert( _uses[bb->_nodes[i]->_idx] == 0, "_use array not clean" );
2361 #endif
2362 
2363   // Force the _uses count to never go to zero for unscheduable pieces
2364   // of the block
2365   for( uint k = 0; k < _bb_start; k++ )
2366     _uses[bb->_nodes[k]->_idx] = 1;
2367   for( uint l = _bb_end; l < bb->_nodes.size(); l++ )
2368     _uses[bb->_nodes[l]->_idx] = 1;
2369 
2370   // Iterate backwards over the instructions in the block.  Don't count the
2371   // branch projections at end or the block header instructions.
2372   for( uint j = _bb_end-1; j >= _bb_start; j-- ) {
2373     Node *n = bb->_nodes[j];
2374     if( n->is_Proj() ) continue; // Projections handled another way
2375 
2376     // Account for all uses
2377     for ( uint k = 0; k < n->len(); k++ ) {
2378       Node *inp = n->in(k);
2379       if (!inp) continue;
2380       assert(inp != n, "no cycles allowed" );
2381       if( _bbs[inp->_idx] == bb ) { // Block-local use?
2382         if( inp->is_Proj() )    // Skip through Proj's
2383           inp = inp->in(0);
2384         ++_uses[inp->_idx];     // Count 1 block-local use
2385       }
2386     }
2387 
2388     // If this instruction has a 0 use count, then it is available
2389     if (!_uses[n->_idx]) {
2390       _current_latency[n->_idx] = _bundle_cycle_number;
2391       AddNodeToAvailableList(n);
2392     }
2393 
2394 #ifndef PRODUCT
2395     if (_cfg->C->trace_opto_output()) {
2396       tty->print("#   uses: %3d: ", _uses[n->_idx]);
2397       n->dump();
2398     }
2399 #endif
2400   }
2401 
2402 #ifndef PRODUCT
2403   if (_cfg->C->trace_opto_output())
2404     tty->print("# <- ComputeUseCount\n");
2405 #endif
2406 }
2407 
2408 // This routine performs scheduling on each basic block in reverse order,
2409 // using instruction latencies and taking into account function unit
2410 // availability.
2411 void Scheduling::DoScheduling() {
2412 #ifndef PRODUCT
2413   if (_cfg->C->trace_opto_output())
2414     tty->print("# -> DoScheduling\n");
2415 #endif
2416 
2417   Block *succ_bb = NULL;
2418   Block *bb;
2419 
2420   // Walk over all the basic blocks in reverse order
2421   for( int i=_cfg->_num_blocks-1; i >= 0; succ_bb = bb, i-- ) {
2422     bb = _cfg->_blocks[i];
2423 
2424 #ifndef PRODUCT
2425     if (_cfg->C->trace_opto_output()) {
2426       tty->print("#  Schedule BB#%03d (initial)\n", i);
2427       for (uint j = 0; j < bb->_nodes.size(); j++)
2428         bb->_nodes[j]->dump();
2429     }
2430 #endif
2431 
2432     // On the head node, skip processing
2433     if( bb == _cfg->_broot )
2434       continue;
2435 
2436     // Skip empty, connector blocks
2437     if (bb->is_connector())
2438       continue;
2439 
2440     // If the following block is not the sole successor of
2441     // this one, then reset the pipeline information
2442     if (bb->_num_succs != 1 || bb->non_connector_successor(0) != succ_bb) {
2443 #ifndef PRODUCT
2444       if (_cfg->C->trace_opto_output()) {
2445         tty->print("*** bundle start of next BB, node %d, for %d instructions\n",
2446                    _next_node->_idx, _bundle_instr_count);
2447       }
2448 #endif
2449       step_and_clear();
2450     }
2451 
2452     // Leave untouched the starting instruction, any Phis, a CreateEx node
2453     // or Top.  bb->_nodes[_bb_start] is the first schedulable instruction.
2454     _bb_end = bb->_nodes.size()-1;
2455     for( _bb_start=1; _bb_start <= _bb_end; _bb_start++ ) {
2456       Node *n = bb->_nodes[_bb_start];
2457       // Things not matched, like Phinodes and ProjNodes don't get scheduled.
2458       // Also, MachIdealNodes do not get scheduled
2459       if( !n->is_Mach() ) continue;     // Skip non-machine nodes
2460       MachNode *mach = n->as_Mach();
2461       int iop = mach->ideal_Opcode();
2462       if( iop == Op_CreateEx ) continue; // CreateEx is pinned
2463       if( iop == Op_Con ) continue;      // Do not schedule Top
2464       if( iop == Op_Node &&     // Do not schedule PhiNodes, ProjNodes
2465           mach->pipeline() == MachNode::pipeline_class() &&
2466           !n->is_SpillCopy() )  // Breakpoints, Prolog, etc
2467         continue;
2468       break;                    // Funny loop structure to be sure...
2469     }
2470     // Compute last "interesting" instruction in block - last instruction we
2471     // might schedule.  _bb_end points just after last schedulable inst.  We
2472     // normally schedule conditional branches (despite them being forced last
2473     // in the block), because they have delay slots we can fill.  Calls all
2474     // have their delay slots filled in the template expansions, so we don't
2475     // bother scheduling them.
2476     Node *last = bb->_nodes[_bb_end];
2477     // Ignore trailing NOPs.
2478     while (_bb_end > 0 && last->is_Mach() &&
2479            last->as_Mach()->ideal_Opcode() == Op_Con) {
2480       last = bb->_nodes[--_bb_end];
2481     }
2482     assert(!last->is_Mach() || last->as_Mach()->ideal_Opcode() != Op_Con, "");
2483     if( last->is_Catch() ||
2484        // Exclude unreachable path case when Halt node is in a separate block.
2485        (_bb_end > 1 && last->is_Mach() && last->as_Mach()->ideal_Opcode() == Op_Halt) ) {
2486       // There must be a prior call.  Skip it.
2487       while( !bb->_nodes[--_bb_end]->is_MachCall() ) {
2488         assert( bb->_nodes[_bb_end]->is_MachProj(), "skipping projections after expected call" );
2489       }
2490     } else if( last->is_MachNullCheck() ) {
2491       // Backup so the last null-checked memory instruction is
2492       // outside the schedulable range. Skip over the nullcheck,
2493       // projection, and the memory nodes.
2494       Node *mem = last->in(1);
2495       do {
2496         _bb_end--;
2497       } while (mem != bb->_nodes[_bb_end]);
2498     } else {
2499       // Set _bb_end to point after last schedulable inst.
2500       _bb_end++;
2501     }
2502 
2503     assert( _bb_start <= _bb_end, "inverted block ends" );
2504 
2505     // Compute the register antidependencies for the basic block
2506     ComputeRegisterAntidependencies(bb);
2507     if (_cfg->C->failing())  return;  // too many D-U pinch points
2508 
2509     // Compute intra-bb latencies for the nodes
2510     ComputeLocalLatenciesForward(bb);
2511 
2512     // Compute the usage within the block, and set the list of all nodes
2513     // in the block that have no uses within the block.
2514     ComputeUseCount(bb);
2515 
2516     // Schedule the remaining instructions in the block
2517     while ( _available.size() > 0 ) {
2518       Node *n = ChooseNodeToBundle();
2519       AddNodeToBundle(n,bb);
2520     }
2521 
2522     assert( _scheduled.size() == _bb_end - _bb_start, "wrong number of instructions" );
2523 #ifdef ASSERT
2524     for( uint l = _bb_start; l < _bb_end; l++ ) {
2525       Node *n = bb->_nodes[l];
2526       uint m;
2527       for( m = 0; m < _bb_end-_bb_start; m++ )
2528         if( _scheduled[m] == n )
2529           break;
2530       assert( m < _bb_end-_bb_start, "instruction missing in schedule" );
2531     }
2532 #endif
2533 
2534     // Now copy the instructions (in reverse order) back to the block
2535     for ( uint k = _bb_start; k < _bb_end; k++ )
2536       bb->_nodes.map(k, _scheduled[_bb_end-k-1]);
2537 
2538 #ifndef PRODUCT
2539     if (_cfg->C->trace_opto_output()) {
2540       tty->print("#  Schedule BB#%03d (final)\n", i);
2541       uint current = 0;
2542       for (uint j = 0; j < bb->_nodes.size(); j++) {
2543         Node *n = bb->_nodes[j];
2544         if( valid_bundle_info(n) ) {
2545           Bundle *bundle = node_bundling(n);
2546           if (bundle->instr_count() > 0 || bundle->flags() > 0) {
2547             tty->print("*** Bundle: ");
2548             bundle->dump();
2549           }
2550           n->dump();
2551         }
2552       }
2553     }
2554 #endif
2555 #ifdef ASSERT
2556   verify_good_schedule(bb,"after block local scheduling");
2557 #endif
2558   }
2559 
2560 #ifndef PRODUCT
2561   if (_cfg->C->trace_opto_output())
2562     tty->print("# <- DoScheduling\n");
2563 #endif
2564 
2565   // Record final node-bundling array location
2566   _regalloc->C->set_node_bundling_base(_node_bundling_base);
2567 
2568 } // end DoScheduling
2569 
2570 //------------------------------verify_good_schedule---------------------------
2571 // Verify that no live-range used in the block is killed in the block by a
2572 // wrong DEF.  This doesn't verify live-ranges that span blocks.
2573 
2574 // Check for edge existence.  Used to avoid adding redundant precedence edges.
2575 static bool edge_from_to( Node *from, Node *to ) {
2576   for( uint i=0; i<from->len(); i++ )
2577     if( from->in(i) == to )
2578       return true;
2579   return false;
2580 }
2581 
2582 #ifdef ASSERT
2583 //------------------------------verify_do_def----------------------------------
2584 void Scheduling::verify_do_def( Node *n, OptoReg::Name def, const char *msg ) {
2585   // Check for bad kills
2586   if( OptoReg::is_valid(def) ) { // Ignore stores & control flow
2587     Node *prior_use = _reg_node[def];
2588     if( prior_use && !edge_from_to(prior_use,n) ) {
2589       tty->print("%s = ",OptoReg::as_VMReg(def)->name());
2590       n->dump();
2591       tty->print_cr("...");
2592       prior_use->dump();
2593       assert(edge_from_to(prior_use,n),msg);
2594     }
2595     _reg_node.map(def,NULL); // Kill live USEs
2596   }
2597 }
2598 
2599 //------------------------------verify_good_schedule---------------------------
2600 void Scheduling::verify_good_schedule( Block *b, const char *msg ) {
2601 
2602   // Zap to something reasonable for the verify code
2603   _reg_node.clear();
2604 
2605   // Walk over the block backwards.  Check to make sure each DEF doesn't
2606   // kill a live value (other than the one it's supposed to).  Add each
2607   // USE to the live set.
2608   for( uint i = b->_nodes.size()-1; i >= _bb_start; i-- ) {
2609     Node *n = b->_nodes[i];
2610     int n_op = n->Opcode();
2611     if( n_op == Op_MachProj && n->ideal_reg() == MachProjNode::fat_proj ) {
2612       // Fat-proj kills a slew of registers
2613       RegMask rm = n->out_RegMask();// Make local copy
2614       while( rm.is_NotEmpty() ) {
2615         OptoReg::Name kill = rm.find_first_elem();
2616         rm.Remove(kill);
2617         verify_do_def( n, kill, msg );
2618       }
2619     } else if( n_op != Op_Node ) { // Avoid brand new antidependence nodes
2620       // Get DEF'd registers the normal way
2621       verify_do_def( n, _regalloc->get_reg_first(n), msg );
2622       verify_do_def( n, _regalloc->get_reg_second(n), msg );
2623     }
2624 
2625     // Now make all USEs live
2626     for( uint i=1; i<n->req(); i++ ) {
2627       Node *def = n->in(i);
2628       assert(def != 0, "input edge required");
2629       OptoReg::Name reg_lo = _regalloc->get_reg_first(def);
2630       OptoReg::Name reg_hi = _regalloc->get_reg_second(def);
2631       if( OptoReg::is_valid(reg_lo) ) {
2632         assert(!_reg_node[reg_lo] || edge_from_to(_reg_node[reg_lo],def), msg);
2633         _reg_node.map(reg_lo,n);
2634       }
2635       if( OptoReg::is_valid(reg_hi) ) {
2636         assert(!_reg_node[reg_hi] || edge_from_to(_reg_node[reg_hi],def), msg);
2637         _reg_node.map(reg_hi,n);
2638       }
2639     }
2640 
2641   }
2642 
2643   // Zap to something reasonable for the Antidependence code
2644   _reg_node.clear();
2645 }
2646 #endif
2647 
2648 // Conditionally add precedence edges.  Avoid putting edges on Projs.
2649 static void add_prec_edge_from_to( Node *from, Node *to ) {
2650   if( from->is_Proj() ) {       // Put precedence edge on Proj's input
2651     assert( from->req() == 1 && (from->len() == 1 || from->in(1)==0), "no precedence edges on projections" );
2652     from = from->in(0);
2653   }
2654   if( from != to &&             // No cycles (for things like LD L0,[L0+4] )
2655       !edge_from_to( from, to ) ) // Avoid duplicate edge
2656     from->add_prec(to);
2657 }
2658 
2659 //------------------------------anti_do_def------------------------------------
2660 void Scheduling::anti_do_def( Block *b, Node *def, OptoReg::Name def_reg, int is_def ) {
2661   if( !OptoReg::is_valid(def_reg) ) // Ignore stores & control flow
2662     return;
2663 
2664   Node *pinch = _reg_node[def_reg]; // Get pinch point
2665   if( !pinch || _bbs[pinch->_idx] != b || // No pinch-point yet?
2666       is_def ) {    // Check for a true def (not a kill)
2667     _reg_node.map(def_reg,def); // Record def/kill as the optimistic pinch-point
2668     return;
2669   }
2670 
2671   Node *kill = def;             // Rename 'def' to more descriptive 'kill'
2672   debug_only( def = (Node*)0xdeadbeef; )
2673 
2674   // After some number of kills there _may_ be a later def
2675   Node *later_def = NULL;
2676 
2677   // Finding a kill requires a real pinch-point.
2678   // Check for not already having a pinch-point.
2679   // Pinch points are Op_Node's.
2680   if( pinch->Opcode() != Op_Node ) { // Or later-def/kill as pinch-point?
2681     later_def = pinch;            // Must be def/kill as optimistic pinch-point
2682     if ( _pinch_free_list.size() > 0) {
2683       pinch = _pinch_free_list.pop();
2684     } else {
2685       pinch = new (_cfg->C, 1) Node(1); // Pinch point to-be
2686     }
2687     if (pinch->_idx >= _regalloc->node_regs_max_index()) {
2688       _cfg->C->record_method_not_compilable("too many D-U pinch points");
2689       return;
2690     }
2691     _bbs.map(pinch->_idx,b);      // Pretend it's valid in this block (lazy init)
2692     _reg_node.map(def_reg,pinch); // Record pinch-point
2693     //_regalloc->set_bad(pinch->_idx); // Already initialized this way.
2694     if( later_def->outcnt() == 0 || later_def->ideal_reg() == MachProjNode::fat_proj ) { // Distinguish def from kill
2695       pinch->init_req(0, _cfg->C->top());     // set not NULL for the next call
2696       add_prec_edge_from_to(later_def,pinch); // Add edge from kill to pinch
2697       later_def = NULL;           // and no later def
2698     }
2699     pinch->set_req(0,later_def);  // Hook later def so we can find it
2700   } else {                        // Else have valid pinch point
2701     if( pinch->in(0) )            // If there is a later-def
2702       later_def = pinch->in(0);   // Get it
2703   }
2704 
2705   // Add output-dependence edge from later def to kill
2706   if( later_def )               // If there is some original def
2707     add_prec_edge_from_to(later_def,kill); // Add edge from def to kill
2708 
2709   // See if current kill is also a use, and so is forced to be the pinch-point.
2710   if( pinch->Opcode() == Op_Node ) {
2711     Node *uses = kill->is_Proj() ? kill->in(0) : kill;
2712     for( uint i=1; i<uses->req(); i++ ) {
2713       if( _regalloc->get_reg_first(uses->in(i)) == def_reg ||
2714           _regalloc->get_reg_second(uses->in(i)) == def_reg ) {
2715         // Yes, found a use/kill pinch-point
2716         pinch->set_req(0,NULL);  //
2717         pinch->replace_by(kill); // Move anti-dep edges up
2718         pinch = kill;
2719         _reg_node.map(def_reg,pinch);
2720         return;
2721       }
2722     }
2723   }
2724 
2725   // Add edge from kill to pinch-point
2726   add_prec_edge_from_to(kill,pinch);
2727 }
2728 
2729 //------------------------------anti_do_use------------------------------------
2730 void Scheduling::anti_do_use( Block *b, Node *use, OptoReg::Name use_reg ) {
2731   if( !OptoReg::is_valid(use_reg) ) // Ignore stores & control flow
2732     return;
2733   Node *pinch = _reg_node[use_reg]; // Get pinch point
2734   // Check for no later def_reg/kill in block
2735   if( pinch && _bbs[pinch->_idx] == b &&
2736       // Use has to be block-local as well
2737       _bbs[use->_idx] == b ) {
2738     if( pinch->Opcode() == Op_Node && // Real pinch-point (not optimistic?)
2739         pinch->req() == 1 ) {   // pinch not yet in block?
2740       pinch->del_req(0);        // yank pointer to later-def, also set flag
2741       // Insert the pinch-point in the block just after the last use
2742       b->_nodes.insert(b->find_node(use)+1,pinch);
2743       _bb_end++;                // Increase size scheduled region in block
2744     }
2745 
2746     add_prec_edge_from_to(pinch,use);
2747   }
2748 }
2749 
2750 //------------------------------ComputeRegisterAntidependences-----------------
2751 // We insert antidependences between the reads and following write of
2752 // allocated registers to prevent illegal code motion. Hopefully, the
2753 // number of added references should be fairly small, especially as we
2754 // are only adding references within the current basic block.
2755 void Scheduling::ComputeRegisterAntidependencies(Block *b) {
2756 
2757 #ifdef ASSERT
2758   verify_good_schedule(b,"before block local scheduling");
2759 #endif
2760 
2761   // A valid schedule, for each register independently, is an endless cycle
2762   // of: a def, then some uses (connected to the def by true dependencies),
2763   // then some kills (defs with no uses), finally the cycle repeats with a new
2764   // def.  The uses are allowed to float relative to each other, as are the
2765   // kills.  No use is allowed to slide past a kill (or def).  This requires
2766   // antidependencies between all uses of a single def and all kills that
2767   // follow, up to the next def.  More edges are redundant, because later defs
2768   // & kills are already serialized with true or antidependencies.  To keep
2769   // the edge count down, we add a 'pinch point' node if there's more than
2770   // one use or more than one kill/def.
2771 
2772   // We add dependencies in one bottom-up pass.
2773 
2774   // For each instruction we handle it's DEFs/KILLs, then it's USEs.
2775 
2776   // For each DEF/KILL, we check to see if there's a prior DEF/KILL for this
2777   // register.  If not, we record the DEF/KILL in _reg_node, the
2778   // register-to-def mapping.  If there is a prior DEF/KILL, we insert a
2779   // "pinch point", a new Node that's in the graph but not in the block.
2780   // We put edges from the prior and current DEF/KILLs to the pinch point.
2781   // We put the pinch point in _reg_node.  If there's already a pinch point
2782   // we merely add an edge from the current DEF/KILL to the pinch point.
2783 
2784   // After doing the DEF/KILLs, we handle USEs.  For each used register, we
2785   // put an edge from the pinch point to the USE.
2786 
2787   // To be expedient, the _reg_node array is pre-allocated for the whole
2788   // compilation.  _reg_node is lazily initialized; it either contains a NULL,
2789   // or a valid def/kill/pinch-point, or a leftover node from some prior
2790   // block.  Leftover node from some prior block is treated like a NULL (no
2791   // prior def, so no anti-dependence needed).  Valid def is distinguished by
2792   // it being in the current block.
2793   bool fat_proj_seen = false;
2794   uint last_safept = _bb_end-1;
2795   Node* end_node         = (_bb_end-1 >= _bb_start) ? b->_nodes[last_safept] : NULL;
2796   Node* last_safept_node = end_node;
2797   for( uint i = _bb_end-1; i >= _bb_start; i-- ) {
2798     Node *n = b->_nodes[i];
2799     int is_def = n->outcnt();   // def if some uses prior to adding precedence edges
2800     if( n->is_MachProj() && n->ideal_reg() == MachProjNode::fat_proj ) {
2801       // Fat-proj kills a slew of registers
2802       // This can add edges to 'n' and obscure whether or not it was a def,
2803       // hence the is_def flag.
2804       fat_proj_seen = true;
2805       RegMask rm = n->out_RegMask();// Make local copy
2806       while( rm.is_NotEmpty() ) {
2807         OptoReg::Name kill = rm.find_first_elem();
2808         rm.Remove(kill);
2809         anti_do_def( b, n, kill, is_def );
2810       }
2811     } else {
2812       // Get DEF'd registers the normal way
2813       anti_do_def( b, n, _regalloc->get_reg_first(n), is_def );
2814       anti_do_def( b, n, _regalloc->get_reg_second(n), is_def );
2815     }
2816 
2817     // Kill projections on a branch should appear to occur on the
2818     // branch, not afterwards, so grab the masks from the projections
2819     // and process them.
2820     if (n->is_MachBranch() || n->is_Mach() && n->as_Mach()->ideal_Opcode() == Op_Jump) {
2821       for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2822         Node* use = n->fast_out(i);
2823         if (use->is_Proj()) {
2824           RegMask rm = use->out_RegMask();// Make local copy
2825           while( rm.is_NotEmpty() ) {
2826             OptoReg::Name kill = rm.find_first_elem();
2827             rm.Remove(kill);
2828             anti_do_def( b, n, kill, false );
2829           }
2830         }
2831       }
2832     }
2833 
2834     // Check each register used by this instruction for a following DEF/KILL
2835     // that must occur afterward and requires an anti-dependence edge.
2836     for( uint j=0; j<n->req(); j++ ) {
2837       Node *def = n->in(j);
2838       if( def ) {
2839         assert( !def->is_MachProj() || def->ideal_reg() != MachProjNode::fat_proj, "" );
2840         anti_do_use( b, n, _regalloc->get_reg_first(def) );
2841         anti_do_use( b, n, _regalloc->get_reg_second(def) );
2842       }
2843     }
2844     // Do not allow defs of new derived values to float above GC
2845     // points unless the base is definitely available at the GC point.
2846 
2847     Node *m = b->_nodes[i];
2848 
2849     // Add precedence edge from following safepoint to use of derived pointer
2850     if( last_safept_node != end_node &&
2851         m != last_safept_node) {
2852       for (uint k = 1; k < m->req(); k++) {
2853         const Type *t = m->in(k)->bottom_type();
2854         if( t->isa_oop_ptr() &&
2855             t->is_ptr()->offset() != 0 ) {
2856           last_safept_node->add_prec( m );
2857           break;
2858         }
2859       }
2860     }
2861 
2862     if( n->jvms() ) {           // Precedence edge from derived to safept
2863       // Check if last_safept_node was moved by pinch-point insertion in anti_do_use()
2864       if( b->_nodes[last_safept] != last_safept_node ) {
2865         last_safept = b->find_node(last_safept_node);
2866       }
2867       for( uint j=last_safept; j > i; j-- ) {
2868         Node *mach = b->_nodes[j];
2869         if( mach->is_Mach() && mach->as_Mach()->ideal_Opcode() == Op_AddP )
2870           mach->add_prec( n );
2871       }
2872       last_safept = i;
2873       last_safept_node = m;
2874     }
2875   }
2876 
2877   if (fat_proj_seen) {
2878     // Garbage collect pinch nodes that were not consumed.
2879     // They are usually created by a fat kill MachProj for a call.
2880     garbage_collect_pinch_nodes();
2881   }
2882 }
2883 
2884 //------------------------------garbage_collect_pinch_nodes-------------------------------
2885 
2886 // Garbage collect pinch nodes for reuse by other blocks.
2887 //
2888 // The block scheduler's insertion of anti-dependence
2889 // edges creates many pinch nodes when the block contains
2890 // 2 or more Calls.  A pinch node is used to prevent a
2891 // combinatorial explosion of edges.  If a set of kills for a
2892 // register is anti-dependent on a set of uses (or defs), rather
2893 // than adding an edge in the graph between each pair of kill
2894 // and use (or def), a pinch is inserted between them:
2895 //
2896 //            use1   use2  use3
2897 //                \   |   /
2898 //                 \  |  /
2899 //                  pinch
2900 //                 /  |  \
2901 //                /   |   \
2902 //            kill1 kill2 kill3
2903 //
2904 // One pinch node is created per register killed when
2905 // the second call is encountered during a backwards pass
2906 // over the block.  Most of these pinch nodes are never
2907 // wired into the graph because the register is never
2908 // used or def'ed in the block.
2909 //
2910 void Scheduling::garbage_collect_pinch_nodes() {
2911 #ifndef PRODUCT
2912     if (_cfg->C->trace_opto_output()) tty->print("Reclaimed pinch nodes:");
2913 #endif
2914     int trace_cnt = 0;
2915     for (uint k = 0; k < _reg_node.Size(); k++) {
2916       Node* pinch = _reg_node[k];
2917       if (pinch != NULL && pinch->Opcode() == Op_Node &&
2918           // no predecence input edges
2919           (pinch->req() == pinch->len() || pinch->in(pinch->req()) == NULL) ) {
2920         cleanup_pinch(pinch);
2921         _pinch_free_list.push(pinch);
2922         _reg_node.map(k, NULL);
2923 #ifndef PRODUCT
2924         if (_cfg->C->trace_opto_output()) {
2925           trace_cnt++;
2926           if (trace_cnt > 40) {
2927             tty->print("\n");
2928             trace_cnt = 0;
2929           }
2930           tty->print(" %d", pinch->_idx);
2931         }
2932 #endif
2933       }
2934     }
2935 #ifndef PRODUCT
2936     if (_cfg->C->trace_opto_output()) tty->print("\n");
2937 #endif
2938 }
2939 
2940 // Clean up a pinch node for reuse.
2941 void Scheduling::cleanup_pinch( Node *pinch ) {
2942   assert (pinch && pinch->Opcode() == Op_Node && pinch->req() == 1, "just checking");
2943 
2944   for (DUIterator_Last imin, i = pinch->last_outs(imin); i >= imin; ) {
2945     Node* use = pinch->last_out(i);
2946     uint uses_found = 0;
2947     for (uint j = use->req(); j < use->len(); j++) {
2948       if (use->in(j) == pinch) {
2949         use->rm_prec(j);
2950         uses_found++;
2951       }
2952     }
2953     assert(uses_found > 0, "must be a precedence edge");
2954     i -= uses_found;    // we deleted 1 or more copies of this edge
2955   }
2956   // May have a later_def entry
2957   pinch->set_req(0, NULL);
2958 }
2959 
2960 //------------------------------print_statistics-------------------------------
2961 #ifndef PRODUCT
2962 
2963 void Scheduling::dump_available() const {
2964   tty->print("#Availist  ");
2965   for (uint i = 0; i < _available.size(); i++)
2966     tty->print(" N%d/l%d", _available[i]->_idx,_current_latency[_available[i]->_idx]);
2967   tty->cr();
2968 }
2969 
2970 // Print Scheduling Statistics
2971 void Scheduling::print_statistics() {
2972   // Print the size added by nops for bundling
2973   tty->print("Nops added %d bytes to total of %d bytes",
2974     _total_nop_size, _total_method_size);
2975   if (_total_method_size > 0)
2976     tty->print(", for %.2f%%",
2977       ((double)_total_nop_size) / ((double) _total_method_size) * 100.0);
2978   tty->print("\n");
2979 
2980   // Print the number of branch shadows filled
2981   if (Pipeline::_branch_has_delay_slot) {
2982     tty->print("Of %d branches, %d had unconditional delay slots filled",
2983       _total_branches, _total_unconditional_delays);
2984     if (_total_branches > 0)
2985       tty->print(", for %.2f%%",
2986         ((double)_total_unconditional_delays) / ((double)_total_branches) * 100.0);
2987     tty->print("\n");
2988   }
2989 
2990   uint total_instructions = 0, total_bundles = 0;
2991 
2992   for (uint i = 1; i <= Pipeline::_max_instrs_per_cycle; i++) {
2993     uint bundle_count   = _total_instructions_per_bundle[i];
2994     total_instructions += bundle_count * i;
2995     total_bundles      += bundle_count;
2996   }
2997 
2998   if (total_bundles > 0)
2999     tty->print("Average ILP (excluding nops) is %.2f\n",
3000       ((double)total_instructions) / ((double)total_bundles));
3001 }
3002 #endif