1 /*
   2  * Copyright (c) 1998, 2014, 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/compiledIC.hpp"
  28 #include "code/debugInfo.hpp"
  29 #include "code/debugInfoRec.hpp"
  30 #include "compiler/compileBroker.hpp"
  31 #include "compiler/oopMap.hpp"
  32 #include "memory/allocation.inline.hpp"
  33 #include "opto/callnode.hpp"
  34 #include "opto/cfgnode.hpp"
  35 #include "opto/locknode.hpp"
  36 #include "opto/machnode.hpp"
  37 #include "opto/output.hpp"
  38 #include "opto/regalloc.hpp"
  39 #include "opto/runtime.hpp"
  40 #include "opto/subnode.hpp"
  41 #include "opto/type.hpp"
  42 #include "runtime/handles.inline.hpp"
  43 #include "utilities/xmlstream.hpp"
  44 
  45 #ifndef PRODUCT
  46 #define DEBUG_ARG(x) , x
  47 #else
  48 #define DEBUG_ARG(x)
  49 #endif
  50 
  51 // Convert Nodes to instruction bits and pass off to the VM
  52 void Compile::Output() {
  53   // RootNode goes
  54   assert( _cfg->get_root_block()->number_of_nodes() == 0, "" );
  55 
  56   // The number of new nodes (mostly MachNop) is proportional to
  57   // the number of java calls and inner loops which are aligned.
  58   if ( C->check_node_count((NodeLimitFudgeFactor + C->java_calls()*3 +
  59                             C->inner_loops()*(OptoLoopAlignment-1)),
  60                            "out of nodes before code generation" ) ) {
  61     return;
  62   }
  63   // Make sure I can find the Start Node
  64   Block *entry = _cfg->get_block(1);
  65   Block *broot = _cfg->get_root_block();
  66 
  67   const StartNode *start = entry->head()->as_Start();
  68 
  69   // Replace StartNode with prolog
  70   MachPrologNode *prolog = new (this) MachPrologNode();
  71   entry->map_node(prolog, 0);
  72   _cfg->map_node_to_block(prolog, entry);
  73   _cfg->unmap_node_from_block(start); // start is no longer in any block
  74 
  75   // Virtual methods need an unverified entry point
  76 
  77   if( is_osr_compilation() ) {
  78     if( PoisonOSREntry ) {
  79       // TODO: Should use a ShouldNotReachHereNode...
  80       _cfg->insert( broot, 0, new (this) MachBreakpointNode() );
  81     }
  82   } else {
  83     if( _method && !_method->flags().is_static() ) {
  84       // Insert unvalidated entry point
  85       _cfg->insert( broot, 0, new (this) MachUEPNode() );
  86     }
  87 
  88   }
  89 
  90 
  91   // Break before main entry point
  92   if( (_method && _method->break_at_execute())
  93 #ifndef PRODUCT
  94     ||(OptoBreakpoint && is_method_compilation())
  95     ||(OptoBreakpointOSR && is_osr_compilation())
  96     ||(OptoBreakpointC2R && !_method)
  97 #endif
  98     ) {
  99     // checking for _method means that OptoBreakpoint does not apply to
 100     // runtime stubs or frame converters
 101     _cfg->insert( entry, 1, new (this) MachBreakpointNode() );
 102   }
 103 
 104   // Insert epilogs before every return
 105   for (uint i = 0; i < _cfg->number_of_blocks(); i++) {
 106     Block* block = _cfg->get_block(i);
 107     if (!block->is_connector() && block->non_connector_successor(0) == _cfg->get_root_block()) { // Found a program exit point?
 108       Node* m = block->end();
 109       if (m->is_Mach() && m->as_Mach()->ideal_Opcode() != Op_Halt) {
 110         MachEpilogNode* epilog = new (this) MachEpilogNode(m->as_Mach()->ideal_Opcode() == Op_Return);
 111         block->add_inst(epilog);
 112         _cfg->map_node_to_block(epilog, block);
 113       }
 114     }
 115   }
 116 
 117 # ifdef ENABLE_ZAP_DEAD_LOCALS
 118   if (ZapDeadCompiledLocals) {
 119     Insert_zap_nodes();
 120   }
 121 # endif
 122 
 123   uint* blk_starts = NEW_RESOURCE_ARRAY(uint, _cfg->number_of_blocks() + 1);
 124   blk_starts[0] = 0;
 125 
 126   // Initialize code buffer and process short branches.
 127   CodeBuffer* cb = init_buffer(blk_starts);
 128 
 129   if (cb == NULL || failing()) {
 130     return;
 131   }
 132 
 133   ScheduleAndBundle();
 134 
 135 #ifndef PRODUCT
 136   if (trace_opto_output()) {
 137     tty->print("\n---- After ScheduleAndBundle ----\n");
 138     for (uint i = 0; i < _cfg->number_of_blocks(); i++) {
 139       tty->print("\nBB#%03d:\n", i);
 140       Block* block = _cfg->get_block(i);
 141       for (uint j = 0; j < block->number_of_nodes(); j++) {
 142         Node* n = block->get_node(j);
 143         OptoReg::Name reg = _regalloc->get_reg_first(n);
 144         tty->print(" %-6s ", reg >= 0 && reg < REG_COUNT ? Matcher::regName[reg] : "");
 145         n->dump();
 146       }
 147     }
 148   }
 149 #endif
 150 
 151   if (failing()) {
 152     return;
 153   }
 154 
 155   BuildOopMaps();
 156 
 157   if (failing())  {
 158     return;
 159   }
 160 
 161   fill_buffer(cb, blk_starts);
 162 }
 163 
 164 bool Compile::need_stack_bang(int frame_size_in_bytes) const {
 165   // Determine if we need to generate a stack overflow check.
 166   // Do it if the method is not a stub function and
 167   // has java calls or has frame size > vm_page_size/8.
 168   // The debug VM checks that deoptimization doesn't trigger an
 169   // unexpected stack overflow (compiled method stack banging should
 170   // guarantee it doesn't happen) so we always need the stack bang in
 171   // a debug VM.
 172   return (UseStackBanging && stub_function() == NULL &&
 173           (has_java_calls() || frame_size_in_bytes > os::vm_page_size()>>3
 174            DEBUG_ONLY(|| true)));
 175 }
 176 
 177 bool Compile::need_register_stack_bang() const {
 178   // Determine if we need to generate a register stack overflow check.
 179   // This is only used on architectures which have split register
 180   // and memory stacks (ie. IA64).
 181   // Bang if the method is not a stub function and has java calls
 182   return (stub_function() == NULL && has_java_calls());
 183 }
 184 
 185 # ifdef ENABLE_ZAP_DEAD_LOCALS
 186 
 187 
 188 // In order to catch compiler oop-map bugs, we have implemented
 189 // a debugging mode called ZapDeadCompilerLocals.
 190 // This mode causes the compiler to insert a call to a runtime routine,
 191 // "zap_dead_locals", right before each place in compiled code
 192 // that could potentially be a gc-point (i.e., a safepoint or oop map point).
 193 // The runtime routine checks that locations mapped as oops are really
 194 // oops, that locations mapped as values do not look like oops,
 195 // and that locations mapped as dead are not used later
 196 // (by zapping them to an invalid address).
 197 
 198 int Compile::_CompiledZap_count = 0;
 199 
 200 void Compile::Insert_zap_nodes() {
 201   bool skip = false;
 202 
 203 
 204   // Dink with static counts because code code without the extra
 205   // runtime calls is MUCH faster for debugging purposes
 206 
 207        if ( CompileZapFirst  ==  0  ) ; // nothing special
 208   else if ( CompileZapFirst  >  CompiledZap_count() )  skip = true;
 209   else if ( CompileZapFirst  == CompiledZap_count() )
 210     warning("starting zap compilation after skipping");
 211 
 212        if ( CompileZapLast  ==  -1  ) ; // nothing special
 213   else if ( CompileZapLast  <   CompiledZap_count() )  skip = true;
 214   else if ( CompileZapLast  ==  CompiledZap_count() )
 215     warning("about to compile last zap");
 216 
 217   ++_CompiledZap_count; // counts skipped zaps, too
 218 
 219   if ( skip )  return;
 220 
 221 
 222   if ( _method == NULL )
 223     return; // no safepoints/oopmaps emitted for calls in stubs,so we don't care
 224 
 225   // Insert call to zap runtime stub before every node with an oop map
 226   for( uint i=0; i<_cfg->number_of_blocks(); i++ ) {
 227     Block *b = _cfg->get_block(i);
 228     for ( uint j = 0;  j < b->number_of_nodes();  ++j ) {
 229       Node *n = b->get_node(j);
 230 
 231       // Determining if we should insert a zap-a-lot node in output.
 232       // We do that for all nodes that has oopmap info, except for calls
 233       // to allocation.  Calls to allocation passes in the old top-of-eden pointer
 234       // and expect the C code to reset it.  Hence, there can be no safepoints between
 235       // the inlined-allocation and the call to new_Java, etc.
 236       // We also cannot zap monitor calls, as they must hold the microlock
 237       // during the call to Zap, which also wants to grab the microlock.
 238       bool insert = n->is_MachSafePoint() && (n->as_MachSafePoint()->oop_map() != NULL);
 239       if ( insert ) { // it is MachSafePoint
 240         if ( !n->is_MachCall() ) {
 241           insert = false;
 242         } else if ( n->is_MachCall() ) {
 243           MachCallNode* call = n->as_MachCall();
 244           if (call->entry_point() == OptoRuntime::new_instance_Java() ||
 245               call->entry_point() == OptoRuntime::new_array_Java() ||
 246               call->entry_point() == OptoRuntime::multianewarray2_Java() ||
 247               call->entry_point() == OptoRuntime::multianewarray3_Java() ||
 248               call->entry_point() == OptoRuntime::multianewarray4_Java() ||
 249               call->entry_point() == OptoRuntime::multianewarray5_Java() ||
 250               call->entry_point() == OptoRuntime::slow_arraycopy_Java() ||
 251               call->entry_point() == OptoRuntime::complete_monitor_locking_Java()
 252               ) {
 253             insert = false;
 254           }
 255         }
 256         if (insert) {
 257           Node *zap = call_zap_node(n->as_MachSafePoint(), i);
 258           b->insert_node(zap, j);
 259           _cfg->map_node_to_block(zap, b);
 260           ++j;
 261         }
 262       }
 263     }
 264   }
 265 }
 266 
 267 
 268 Node* Compile::call_zap_node(MachSafePointNode* node_to_check, int block_no) {
 269   const TypeFunc *tf = OptoRuntime::zap_dead_locals_Type();
 270   CallStaticJavaNode* ideal_node =
 271     new (this) CallStaticJavaNode( tf,
 272          OptoRuntime::zap_dead_locals_stub(_method->flags().is_native()),
 273                        "call zap dead locals stub", 0, TypePtr::BOTTOM);
 274   // We need to copy the OopMap from the site we're zapping at.
 275   // We have to make a copy, because the zap site might not be
 276   // a call site, and zap_dead is a call site.
 277   OopMap* clone = node_to_check->oop_map()->deep_copy();
 278 
 279   // Add the cloned OopMap to the zap node
 280   ideal_node->set_oop_map(clone);
 281   return _matcher->match_sfpt(ideal_node);
 282 }
 283 
 284 bool Compile::is_node_getting_a_safepoint( Node* n) {
 285   // This code duplicates the logic prior to the call of add_safepoint
 286   // below in this file.
 287   if( n->is_MachSafePoint() ) return true;
 288   return false;
 289 }
 290 
 291 # endif // ENABLE_ZAP_DEAD_LOCALS
 292 
 293 // Compute the size of first NumberOfLoopInstrToAlign instructions at the top
 294 // of a loop. When aligning a loop we need to provide enough instructions
 295 // in cpu's fetch buffer to feed decoders. The loop alignment could be
 296 // avoided if we have enough instructions in fetch buffer at the head of a loop.
 297 // By default, the size is set to 999999 by Block's constructor so that
 298 // a loop will be aligned if the size is not reset here.
 299 //
 300 // Note: Mach instructions could contain several HW instructions
 301 // so the size is estimated only.
 302 //
 303 void Compile::compute_loop_first_inst_sizes() {
 304   // The next condition is used to gate the loop alignment optimization.
 305   // Don't aligned a loop if there are enough instructions at the head of a loop
 306   // or alignment padding is larger then MaxLoopPad. By default, MaxLoopPad
 307   // is equal to OptoLoopAlignment-1 except on new Intel cpus, where it is
 308   // equal to 11 bytes which is the largest address NOP instruction.
 309   if (MaxLoopPad < OptoLoopAlignment - 1) {
 310     uint last_block = _cfg->number_of_blocks() - 1;
 311     for (uint i = 1; i <= last_block; i++) {
 312       Block* block = _cfg->get_block(i);
 313       // Check the first loop's block which requires an alignment.
 314       if (block->loop_alignment() > (uint)relocInfo::addr_unit()) {
 315         uint sum_size = 0;
 316         uint inst_cnt = NumberOfLoopInstrToAlign;
 317         inst_cnt = block->compute_first_inst_size(sum_size, inst_cnt, _regalloc);
 318 
 319         // Check subsequent fallthrough blocks if the loop's first
 320         // block(s) does not have enough instructions.
 321         Block *nb = block;
 322         while(inst_cnt > 0 &&
 323               i < last_block &&
 324               !_cfg->get_block(i + 1)->has_loop_alignment() &&
 325               !nb->has_successor(block)) {
 326           i++;
 327           nb = _cfg->get_block(i);
 328           inst_cnt  = nb->compute_first_inst_size(sum_size, inst_cnt, _regalloc);
 329         } // while( inst_cnt > 0 && i < last_block  )
 330 
 331         block->set_first_inst_size(sum_size);
 332       } // f( b->head()->is_Loop() )
 333     } // for( i <= last_block )
 334   } // if( MaxLoopPad < OptoLoopAlignment-1 )
 335 }
 336 
 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   // Compute size of each block, method size, and relocation information size
 341   uint nblocks  = _cfg->number_of_blocks();
 342 
 343   uint*      jmp_offset = NEW_RESOURCE_ARRAY(uint,nblocks);
 344   uint*      jmp_size   = NEW_RESOURCE_ARRAY(uint,nblocks);
 345   int*       jmp_nidx   = NEW_RESOURCE_ARRAY(int ,nblocks);
 346 
 347   // Collect worst case block paddings
 348   int* block_worst_case_pad = NEW_RESOURCE_ARRAY(int, nblocks);
 349   memset(block_worst_case_pad, 0, nblocks * sizeof(int));
 350 
 351   DEBUG_ONLY( uint *jmp_target = NEW_RESOURCE_ARRAY(uint,nblocks); )
 352   DEBUG_ONLY( uint *jmp_rule = NEW_RESOURCE_ARRAY(uint,nblocks); )
 353 
 354   bool has_short_branch_candidate = false;
 355 
 356   // Initialize the sizes to 0
 357   code_size  = 0;          // Size in bytes of generated code
 358   stub_size  = 0;          // Size in bytes of all stub entries
 359   // Size in bytes of all relocation entries, including those in local stubs.
 360   // Start with 2-bytes of reloc info for the unvalidated entry point
 361   reloc_size = 1;          // Number of relocation entries
 362 
 363   // Make three passes.  The first computes pessimistic blk_starts,
 364   // relative jmp_offset and reloc_size information.  The second performs
 365   // short branch substitution using the pessimistic sizing.  The
 366   // third inserts nops where needed.
 367 
 368   // Step one, perform a pessimistic sizing pass.
 369   uint last_call_adr = max_uint;
 370   uint last_avoid_back_to_back_adr = max_uint;
 371   uint nop_size = (new (this) MachNopNode())->size(_regalloc);
 372   for (uint i = 0; i < nblocks; i++) { // For all blocks
 373     Block* block = _cfg->get_block(i);
 374 
 375     // During short branch replacement, we store the relative (to blk_starts)
 376     // offset of jump in jmp_offset, rather than the absolute offset of jump.
 377     // This is so that we do not need to recompute sizes of all nodes when
 378     // we compute correct blk_starts in our next sizing pass.
 379     jmp_offset[i] = 0;
 380     jmp_size[i]   = 0;
 381     jmp_nidx[i]   = -1;
 382     DEBUG_ONLY( jmp_target[i] = 0; )
 383     DEBUG_ONLY( jmp_rule[i]   = 0; )
 384 
 385     // Sum all instruction sizes to compute block size
 386     uint last_inst = block->number_of_nodes();
 387     uint blk_size = 0;
 388     for (uint j = 0; j < last_inst; j++) {
 389       Node* nj = block->get_node(j);
 390       // Handle machine instruction nodes
 391       if (nj->is_Mach()) {
 392         MachNode *mach = nj->as_Mach();
 393         blk_size += (mach->alignment_required() - 1) * relocInfo::addr_unit(); // assume worst case padding
 394         reloc_size += mach->reloc();
 395         if (mach->is_MachCall()) {
 396           // add size information for trampoline stub
 397           // class CallStubImpl is platform-specific and defined in the *.ad files.
 398           stub_size  += CallStubImpl::size_call_trampoline();
 399           reloc_size += CallStubImpl::reloc_call_trampoline();
 400 
 401           MachCallNode *mcall = mach->as_MachCall();
 402           // This destination address is NOT PC-relative
 403 
 404           mcall->method_set((intptr_t)mcall->entry_point());
 405 
 406           if (mcall->is_MachCallJava() && mcall->as_MachCallJava()->_method) {
 407             stub_size  += CompiledStaticCall::to_interp_stub_size();
 408             reloc_size += CompiledStaticCall::reloc_to_interp_stub();
 409           }
 410         } else if (mach->is_MachSafePoint()) {
 411           // If call/safepoint are adjacent, account for possible
 412           // nop to disambiguate the two safepoints.
 413           // ScheduleAndBundle() can rearrange nodes in a block,
 414           // check for all offsets inside this block.
 415           if (last_call_adr >= blk_starts[i]) {
 416             blk_size += nop_size;
 417           }
 418         }
 419         if (mach->avoid_back_to_back(MachNode::AVOID_BEFORE)) {
 420           // Nop is inserted between "avoid back to back" instructions.
 421           // ScheduleAndBundle() can rearrange nodes in a block,
 422           // check for all offsets inside this block.
 423           if (last_avoid_back_to_back_adr >= blk_starts[i]) {
 424             blk_size += nop_size;
 425           }
 426         }
 427         if (mach->may_be_short_branch()) {
 428           if (!nj->is_MachBranch()) {
 429 #ifndef PRODUCT
 430             nj->dump(3);
 431 #endif
 432             Unimplemented();
 433           }
 434           assert(jmp_nidx[i] == -1, "block should have only one branch");
 435           jmp_offset[i] = blk_size;
 436           jmp_size[i]   = nj->size(_regalloc);
 437           jmp_nidx[i]   = j;
 438           has_short_branch_candidate = true;
 439         }
 440       }
 441       blk_size += nj->size(_regalloc);
 442       // Remember end of call offset
 443       if (nj->is_MachCall() && !nj->is_MachCallLeaf()) {
 444         last_call_adr = blk_starts[i]+blk_size;
 445       }
 446       // Remember end of avoid_back_to_back offset
 447       if (nj->is_Mach() && nj->as_Mach()->avoid_back_to_back(MachNode::AVOID_AFTER)) {
 448         last_avoid_back_to_back_adr = blk_starts[i]+blk_size;
 449       }
 450     }
 451 
 452     // When the next block starts a loop, we may insert pad NOP
 453     // instructions.  Since we cannot know our future alignment,
 454     // assume the worst.
 455     if (i < nblocks - 1) {
 456       Block* nb = _cfg->get_block(i + 1);
 457       int max_loop_pad = nb->code_alignment()-relocInfo::addr_unit();
 458       if (max_loop_pad > 0) {
 459         assert(is_power_of_2(max_loop_pad+relocInfo::addr_unit()), "");
 460         // Adjust last_call_adr and/or last_avoid_back_to_back_adr.
 461         // If either is the last instruction in this block, bump by
 462         // max_loop_pad in lock-step with blk_size, so sizing
 463         // calculations in subsequent blocks still can conservatively
 464         // detect that it may the last instruction in this block.
 465         if (last_call_adr == blk_starts[i]+blk_size) {
 466           last_call_adr += max_loop_pad;
 467         }
 468         if (last_avoid_back_to_back_adr == blk_starts[i]+blk_size) {
 469           last_avoid_back_to_back_adr += max_loop_pad;
 470         }
 471         blk_size += max_loop_pad;
 472         block_worst_case_pad[i + 1] = max_loop_pad;
 473       }
 474     }
 475 
 476     // Save block size; update total method size
 477     blk_starts[i+1] = blk_starts[i]+blk_size;
 478   }
 479 
 480   // Step two, replace eligible long jumps.
 481   bool progress = true;
 482   uint last_may_be_short_branch_adr = max_uint;
 483   while (has_short_branch_candidate && progress) {
 484     progress = false;
 485     has_short_branch_candidate = false;
 486     int adjust_block_start = 0;
 487     for (uint i = 0; i < nblocks; i++) {
 488       Block* block = _cfg->get_block(i);
 489       int idx = jmp_nidx[i];
 490       MachNode* mach = (idx == -1) ? NULL: block->get_node(idx)->as_Mach();
 491       if (mach != NULL && mach->may_be_short_branch()) {
 492 #ifdef ASSERT
 493         assert(jmp_size[i] > 0 && mach->is_MachBranch(), "sanity");
 494         int j;
 495         // Find the branch; ignore trailing NOPs.
 496         for (j = block->number_of_nodes()-1; j>=0; j--) {
 497           Node* n = block->get_node(j);
 498           if (!n->is_Mach() || n->as_Mach()->ideal_Opcode() != Op_Con)
 499             break;
 500         }
 501         assert(j >= 0 && j == idx && block->get_node(j) == (Node*)mach, "sanity");
 502 #endif
 503         int br_size = jmp_size[i];
 504         int br_offs = blk_starts[i] + jmp_offset[i];
 505 
 506         // This requires the TRUE branch target be in succs[0]
 507         uint bnum = block->non_connector_successor(0)->_pre_order;
 508         int offset = blk_starts[bnum] - br_offs;
 509         if (bnum > i) { // adjust following block's offset
 510           offset -= adjust_block_start;
 511         }
 512 
 513         // This block can be a loop header, account for the padding
 514         // in the previous block.
 515         int block_padding = block_worst_case_pad[i];
 516         assert(i == 0 || block_padding == 0 || br_offs >= block_padding, "Should have at least a padding on top");
 517         // In the following code a nop could be inserted before
 518         // the branch which will increase the backward distance.
 519         bool needs_padding = ((uint)(br_offs - block_padding) == last_may_be_short_branch_adr);
 520         assert(!needs_padding || jmp_offset[i] == 0, "padding only branches at the beginning of block");
 521 
 522         if (needs_padding && offset <= 0)
 523           offset -= nop_size;
 524 
 525         if (_matcher->is_short_branch_offset(mach->rule(), br_size, offset)) {
 526           // We've got a winner.  Replace this branch.
 527           MachNode* replacement = mach->as_MachBranch()->short_branch_version(this);
 528 
 529           // Update the jmp_size.
 530           int new_size = replacement->size(_regalloc);
 531           int diff     = br_size - new_size;
 532           assert(diff >= (int)nop_size, "short_branch size should be smaller");
 533           // Conservatively take into account padding between
 534           // avoid_back_to_back branches. Previous branch could be
 535           // converted into avoid_back_to_back branch during next
 536           // rounds.
 537           if (needs_padding && replacement->avoid_back_to_back(MachNode::AVOID_BEFORE)) {
 538             jmp_offset[i] += nop_size;
 539             diff -= nop_size;
 540           }
 541           adjust_block_start += diff;
 542           block->map_node(replacement, idx);
 543           mach->subsume_by(replacement, C);
 544           mach = replacement;
 545           progress = true;
 546 
 547           jmp_size[i] = new_size;
 548           DEBUG_ONLY( jmp_target[i] = bnum; );
 549           DEBUG_ONLY( jmp_rule[i] = mach->rule(); );
 550         } else {
 551           // The jump distance is not short, try again during next iteration.
 552           has_short_branch_candidate = true;
 553         }
 554       } // (mach->may_be_short_branch())
 555       if (mach != NULL && (mach->may_be_short_branch() ||
 556                            mach->avoid_back_to_back(MachNode::AVOID_AFTER))) {
 557         last_may_be_short_branch_adr = blk_starts[i] + jmp_offset[i] + jmp_size[i];
 558       }
 559       blk_starts[i+1] -= adjust_block_start;
 560     }
 561   }
 562 
 563 #ifdef ASSERT
 564   for (uint i = 0; i < nblocks; i++) { // For all blocks
 565     if (jmp_target[i] != 0) {
 566       int br_size = jmp_size[i];
 567       int offset = blk_starts[jmp_target[i]]-(blk_starts[i] + jmp_offset[i]);
 568       if (!_matcher->is_short_branch_offset(jmp_rule[i], br_size, offset)) {
 569         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]);
 570       }
 571       assert(_matcher->is_short_branch_offset(jmp_rule[i], br_size, offset), "Displacement too large for short jmp");
 572     }
 573   }
 574 #endif
 575 
 576   // Step 3, compute the offsets of all blocks, will be done in fill_buffer()
 577   // after ScheduleAndBundle().
 578 
 579   // ------------------
 580   // Compute size for code buffer
 581   code_size = blk_starts[nblocks];
 582 
 583   // Relocation records
 584   reloc_size += 1;              // Relo entry for exception handler
 585 
 586   // Adjust reloc_size to number of record of relocation info
 587   // Min is 2 bytes, max is probably 6 or 8, with a tax up to 25% for
 588   // a relocation index.
 589   // The CodeBuffer will expand the locs array if this estimate is too low.
 590   reloc_size *= 10 / sizeof(relocInfo);
 591 }
 592 
 593 //------------------------------FillLocArray-----------------------------------
 594 // Create a bit of debug info and append it to the array.  The mapping is from
 595 // Java local or expression stack to constant, register or stack-slot.  For
 596 // doubles, insert 2 mappings and return 1 (to tell the caller that the next
 597 // entry has been taken care of and caller should skip it).
 598 static LocationValue *new_loc_value( PhaseRegAlloc *ra, OptoReg::Name regnum, Location::Type l_type ) {
 599   // This should never have accepted Bad before
 600   assert(OptoReg::is_valid(regnum), "location must be valid");
 601   return (OptoReg::is_reg(regnum))
 602     ? new LocationValue(Location::new_reg_loc(l_type, OptoReg::as_VMReg(regnum)) )
 603     : new LocationValue(Location::new_stk_loc(l_type,  ra->reg2offset(regnum)));
 604 }
 605 
 606 
 607 ObjectValue*
 608 Compile::sv_for_node_id(GrowableArray<ScopeValue*> *objs, int id) {
 609   for (int i = 0; i < objs->length(); i++) {
 610     assert(objs->at(i)->is_object(), "corrupt object cache");
 611     ObjectValue* sv = (ObjectValue*) objs->at(i);
 612     if (sv->id() == id) {
 613       return sv;
 614     }
 615   }
 616   // Otherwise..
 617   return NULL;
 618 }
 619 
 620 void Compile::set_sv_for_object_node(GrowableArray<ScopeValue*> *objs,
 621                                      ObjectValue* sv ) {
 622   assert(sv_for_node_id(objs, sv->id()) == NULL, "Precondition");
 623   objs->append(sv);
 624 }
 625 
 626 
 627 void Compile::FillLocArray( int idx, MachSafePointNode* sfpt, Node *local,
 628                             GrowableArray<ScopeValue*> *array,
 629                             GrowableArray<ScopeValue*> *objs ) {
 630   assert( local, "use _top instead of null" );
 631   if (array->length() != idx) {
 632     assert(array->length() == idx + 1, "Unexpected array count");
 633     // Old functionality:
 634     //   return
 635     // New functionality:
 636     //   Assert if the local is not top. In product mode let the new node
 637     //   override the old entry.
 638     assert(local == top(), "LocArray collision");
 639     if (local == top()) {
 640       return;
 641     }
 642     array->pop();
 643   }
 644   const Type *t = local->bottom_type();
 645 
 646   // Is it a safepoint scalar object node?
 647   if (local->is_SafePointScalarObject()) {
 648     SafePointScalarObjectNode* spobj = local->as_SafePointScalarObject();
 649 
 650     ObjectValue* sv = Compile::sv_for_node_id(objs, spobj->_idx);
 651     if (sv == NULL) {
 652       ciKlass* cik = t->is_oopptr()->klass();
 653       assert(cik->is_instance_klass() ||
 654              cik->is_array_klass(), "Not supported allocation.");
 655       sv = new ObjectValue(spobj->_idx,
 656                            new ConstantOopWriteValue(cik->java_mirror()->constant_encoding()));
 657       Compile::set_sv_for_object_node(objs, sv);
 658 
 659       uint first_ind = spobj->first_index(sfpt->jvms());
 660       for (uint i = 0; i < spobj->n_fields(); i++) {
 661         Node* fld_node = sfpt->in(first_ind+i);
 662         (void)FillLocArray(sv->field_values()->length(), sfpt, fld_node, sv->field_values(), objs);
 663       }
 664     }
 665     array->append(sv);
 666     return;
 667   }
 668 
 669   // Grab the register number for the local
 670   OptoReg::Name regnum = _regalloc->get_reg_first(local);
 671   if( OptoReg::is_valid(regnum) ) {// Got a register/stack?
 672     // Record the double as two float registers.
 673     // The register mask for such a value always specifies two adjacent
 674     // float registers, with the lower register number even.
 675     // Normally, the allocation of high and low words to these registers
 676     // is irrelevant, because nearly all operations on register pairs
 677     // (e.g., StoreD) treat them as a single unit.
 678     // Here, we assume in addition that the words in these two registers
 679     // stored "naturally" (by operations like StoreD and double stores
 680     // within the interpreter) such that the lower-numbered register
 681     // is written to the lower memory address.  This may seem like
 682     // a machine dependency, but it is not--it is a requirement on
 683     // the author of the <arch>.ad file to ensure that, for every
 684     // even/odd double-register pair to which a double may be allocated,
 685     // the word in the even single-register is stored to the first
 686     // memory word.  (Note that register numbers are completely
 687     // arbitrary, and are not tied to any machine-level encodings.)
 688 #ifdef _LP64
 689     if( t->base() == Type::DoubleBot || t->base() == Type::DoubleCon ) {
 690       array->append(new ConstantIntValue(0));
 691       array->append(new_loc_value( _regalloc, regnum, Location::dbl ));
 692     } else if ( t->base() == Type::Long ) {
 693       array->append(new ConstantIntValue(0));
 694       array->append(new_loc_value( _regalloc, regnum, Location::lng ));
 695     } else if ( t->base() == Type::RawPtr ) {
 696       // jsr/ret return address which must be restored into a the full
 697       // width 64-bit stack slot.
 698       array->append(new_loc_value( _regalloc, regnum, Location::lng ));
 699     }
 700 #else //_LP64
 701 #ifdef SPARC
 702     if (t->base() == Type::Long && OptoReg::is_reg(regnum)) {
 703       // For SPARC we have to swap high and low words for
 704       // long values stored in a single-register (g0-g7).
 705       array->append(new_loc_value( _regalloc,              regnum   , Location::normal ));
 706       array->append(new_loc_value( _regalloc, OptoReg::add(regnum,1), Location::normal ));
 707     } else
 708 #endif //SPARC
 709     if( t->base() == Type::DoubleBot || t->base() == Type::DoubleCon || t->base() == Type::Long ) {
 710       // Repack the double/long as two jints.
 711       // The convention the interpreter uses is that the second local
 712       // holds the first raw word of the native double representation.
 713       // This is actually reasonable, since locals and stack arrays
 714       // grow downwards in all implementations.
 715       // (If, on some machine, the interpreter's Java locals or stack
 716       // were to grow upwards, the embedded doubles would be word-swapped.)
 717       array->append(new_loc_value( _regalloc, OptoReg::add(regnum,1), Location::normal ));
 718       array->append(new_loc_value( _regalloc,              regnum   , Location::normal ));
 719     }
 720 #endif //_LP64
 721     else if( (t->base() == Type::FloatBot || t->base() == Type::FloatCon) &&
 722                OptoReg::is_reg(regnum) ) {
 723       array->append(new_loc_value( _regalloc, regnum, Matcher::float_in_double()
 724                                    ? Location::float_in_dbl : Location::normal ));
 725     } else if( t->base() == Type::Int && OptoReg::is_reg(regnum) ) {
 726       array->append(new_loc_value( _regalloc, regnum, Matcher::int_in_long
 727                                    ? Location::int_in_long : Location::normal ));
 728     } else if( t->base() == Type::NarrowOop ) {
 729       array->append(new_loc_value( _regalloc, regnum, Location::narrowoop ));
 730     } else {
 731       array->append(new_loc_value( _regalloc, regnum, _regalloc->is_oop(local) ? Location::oop : Location::normal ));
 732     }
 733     return;
 734   }
 735 
 736   // No register.  It must be constant data.
 737   switch (t->base()) {
 738   case Type::Half:              // Second half of a double
 739     ShouldNotReachHere();       // Caller should skip 2nd halves
 740     break;
 741   case Type::AnyPtr:
 742     array->append(new ConstantOopWriteValue(NULL));
 743     break;
 744   case Type::AryPtr:
 745   case Type::InstPtr:          // fall through
 746     array->append(new ConstantOopWriteValue(t->isa_oopptr()->const_oop()->constant_encoding()));
 747     break;
 748   case Type::NarrowOop:
 749     if (t == TypeNarrowOop::NULL_PTR) {
 750       array->append(new ConstantOopWriteValue(NULL));
 751     } else {
 752       array->append(new ConstantOopWriteValue(t->make_ptr()->isa_oopptr()->const_oop()->constant_encoding()));
 753     }
 754     break;
 755   case Type::Int:
 756     array->append(new ConstantIntValue(t->is_int()->get_con()));
 757     break;
 758   case Type::RawPtr:
 759     // A return address (T_ADDRESS).
 760     assert((intptr_t)t->is_ptr()->get_con() < (intptr_t)0x10000, "must be a valid BCI");
 761 #ifdef _LP64
 762     // Must be restored to the full-width 64-bit stack slot.
 763     array->append(new ConstantLongValue(t->is_ptr()->get_con()));
 764 #else
 765     array->append(new ConstantIntValue(t->is_ptr()->get_con()));
 766 #endif
 767     break;
 768   case Type::FloatCon: {
 769     float f = t->is_float_constant()->getf();
 770     array->append(new ConstantIntValue(jint_cast(f)));
 771     break;
 772   }
 773   case Type::DoubleCon: {
 774     jdouble d = t->is_double_constant()->getd();
 775 #ifdef _LP64
 776     array->append(new ConstantIntValue(0));
 777     array->append(new ConstantDoubleValue(d));
 778 #else
 779     // Repack the double as two jints.
 780     // The convention the interpreter uses is that the second local
 781     // holds the first raw word of the native double representation.
 782     // This is actually reasonable, since locals and stack arrays
 783     // grow downwards in all implementations.
 784     // (If, on some machine, the interpreter's Java locals or stack
 785     // were to grow upwards, the embedded doubles would be word-swapped.)
 786     jlong_accessor acc;
 787     acc.long_value = jlong_cast(d);
 788     array->append(new ConstantIntValue(acc.words[1]));
 789     array->append(new ConstantIntValue(acc.words[0]));
 790 #endif
 791     break;
 792   }
 793   case Type::Long: {
 794     jlong d = t->is_long()->get_con();
 795 #ifdef _LP64
 796     array->append(new ConstantIntValue(0));
 797     array->append(new ConstantLongValue(d));
 798 #else
 799     // Repack the long as two jints.
 800     // The convention the interpreter uses is that the second local
 801     // holds the first raw word of the native double representation.
 802     // This is actually reasonable, since locals and stack arrays
 803     // grow downwards in all implementations.
 804     // (If, on some machine, the interpreter's Java locals or stack
 805     // were to grow upwards, the embedded doubles would be word-swapped.)
 806     jlong_accessor acc;
 807     acc.long_value = d;
 808     array->append(new ConstantIntValue(acc.words[1]));
 809     array->append(new ConstantIntValue(acc.words[0]));
 810 #endif
 811     break;
 812   }
 813   case Type::Top:               // Add an illegal value here
 814     array->append(new LocationValue(Location()));
 815     break;
 816   default:
 817     ShouldNotReachHere();
 818     break;
 819   }
 820 }
 821 
 822 // Determine if this node starts a bundle
 823 bool Compile::starts_bundle(const Node *n) const {
 824   return (_node_bundling_limit > n->_idx &&
 825           _node_bundling_base[n->_idx].starts_bundle());
 826 }
 827 
 828 //--------------------------Process_OopMap_Node--------------------------------
 829 void Compile::Process_OopMap_Node(MachNode *mach, int current_offset) {
 830 
 831   // Handle special safepoint nodes for synchronization
 832   MachSafePointNode *sfn   = mach->as_MachSafePoint();
 833   MachCallNode      *mcall;
 834 
 835 #ifdef ENABLE_ZAP_DEAD_LOCALS
 836   assert( is_node_getting_a_safepoint(mach),  "logic does not match; false negative");
 837 #endif
 838 
 839   int safepoint_pc_offset = current_offset;
 840   bool is_method_handle_invoke = false;
 841   bool return_oop = false;
 842 
 843   // Add the safepoint in the DebugInfoRecorder
 844   if( !mach->is_MachCall() ) {
 845     mcall = NULL;
 846     debug_info()->add_safepoint(safepoint_pc_offset, sfn->_oop_map);
 847   } else {
 848     mcall = mach->as_MachCall();
 849 
 850     // Is the call a MethodHandle call?
 851     if (mcall->is_MachCallJava()) {
 852       if (mcall->as_MachCallJava()->_method_handle_invoke) {
 853         assert(has_method_handle_invokes(), "must have been set during call generation");
 854         is_method_handle_invoke = true;
 855       }
 856     }
 857 
 858     // Check if a call returns an object.
 859     if (mcall->returns_pointer()) {
 860       return_oop = true;
 861     }
 862     safepoint_pc_offset += mcall->ret_addr_offset();
 863     debug_info()->add_safepoint(safepoint_pc_offset, mcall->_oop_map);
 864   }
 865 
 866   // Loop over the JVMState list to add scope information
 867   // Do not skip safepoints with a NULL method, they need monitor info
 868   JVMState* youngest_jvms = sfn->jvms();
 869   int max_depth = youngest_jvms->depth();
 870 
 871   // Allocate the object pool for scalar-replaced objects -- the map from
 872   // small-integer keys (which can be recorded in the local and ostack
 873   // arrays) to descriptions of the object state.
 874   GrowableArray<ScopeValue*> *objs = new GrowableArray<ScopeValue*>();
 875 
 876   // Visit scopes from oldest to youngest.
 877   for (int depth = 1; depth <= max_depth; depth++) {
 878     JVMState* jvms = youngest_jvms->of_depth(depth);
 879     int idx;
 880     ciMethod* method = jvms->has_method() ? jvms->method() : NULL;
 881     // Safepoints that do not have method() set only provide oop-map and monitor info
 882     // to support GC; these do not support deoptimization.
 883     int num_locs = (method == NULL) ? 0 : jvms->loc_size();
 884     int num_exps = (method == NULL) ? 0 : jvms->stk_size();
 885     int num_mon  = jvms->nof_monitors();
 886     assert(method == NULL || jvms->bci() < 0 || num_locs == method->max_locals(),
 887            "JVMS local count must match that of the method");
 888 
 889     // Add Local and Expression Stack Information
 890 
 891     // Insert locals into the locarray
 892     GrowableArray<ScopeValue*> *locarray = new GrowableArray<ScopeValue*>(num_locs);
 893     for( idx = 0; idx < num_locs; idx++ ) {
 894       FillLocArray( idx, sfn, sfn->local(jvms, idx), locarray, objs );
 895     }
 896 
 897     // Insert expression stack entries into the exparray
 898     GrowableArray<ScopeValue*> *exparray = new GrowableArray<ScopeValue*>(num_exps);
 899     for( idx = 0; idx < num_exps; idx++ ) {
 900       FillLocArray( idx,  sfn, sfn->stack(jvms, idx), exparray, objs );
 901     }
 902 
 903     // Add in mappings of the monitors
 904     assert( !method ||
 905             !method->is_synchronized() ||
 906             method->is_native() ||
 907             num_mon > 0 ||
 908             !GenerateSynchronizationCode,
 909             "monitors must always exist for synchronized methods");
 910 
 911     // Build the growable array of ScopeValues for exp stack
 912     GrowableArray<MonitorValue*> *monarray = new GrowableArray<MonitorValue*>(num_mon);
 913 
 914     // Loop over monitors and insert into array
 915     for (idx = 0; idx < num_mon; idx++) {
 916       // Grab the node that defines this monitor
 917       Node* box_node = sfn->monitor_box(jvms, idx);
 918       Node* obj_node = sfn->monitor_obj(jvms, idx);
 919 
 920       // Create ScopeValue for object
 921       ScopeValue *scval = NULL;
 922 
 923       if (obj_node->is_SafePointScalarObject()) {
 924         SafePointScalarObjectNode* spobj = obj_node->as_SafePointScalarObject();
 925         scval = Compile::sv_for_node_id(objs, spobj->_idx);
 926         if (scval == NULL) {
 927           const Type *t = spobj->bottom_type();
 928           ciKlass* cik = t->is_oopptr()->klass();
 929           assert(cik->is_instance_klass() ||
 930                  cik->is_array_klass(), "Not supported allocation.");
 931           ObjectValue* sv = new ObjectValue(spobj->_idx,
 932                                             new ConstantOopWriteValue(cik->java_mirror()->constant_encoding()));
 933           Compile::set_sv_for_object_node(objs, sv);
 934 
 935           uint first_ind = spobj->first_index(youngest_jvms);
 936           for (uint i = 0; i < spobj->n_fields(); i++) {
 937             Node* fld_node = sfn->in(first_ind+i);
 938             (void)FillLocArray(sv->field_values()->length(), sfn, fld_node, sv->field_values(), objs);
 939           }
 940           scval = sv;
 941         }
 942       } else if (!obj_node->is_Con()) {
 943         OptoReg::Name obj_reg = _regalloc->get_reg_first(obj_node);
 944         if( obj_node->bottom_type()->base() == Type::NarrowOop ) {
 945           scval = new_loc_value( _regalloc, obj_reg, Location::narrowoop );
 946         } else {
 947           scval = new_loc_value( _regalloc, obj_reg, Location::oop );
 948         }
 949       } else {
 950         const TypePtr *tp = obj_node->get_ptr_type();
 951         scval = new ConstantOopWriteValue(tp->is_oopptr()->const_oop()->constant_encoding());
 952       }
 953 
 954       OptoReg::Name box_reg = BoxLockNode::reg(box_node);
 955       Location basic_lock = Location::new_stk_loc(Location::normal,_regalloc->reg2offset(box_reg));
 956       bool eliminated = (box_node->is_BoxLock() && box_node->as_BoxLock()->is_eliminated());
 957       monarray->append(new MonitorValue(scval, basic_lock, eliminated));
 958     }
 959 
 960     // We dump the object pool first, since deoptimization reads it in first.
 961     debug_info()->dump_object_pool(objs);
 962 
 963     // Build first class objects to pass to scope
 964     DebugToken *locvals = debug_info()->create_scope_values(locarray);
 965     DebugToken *expvals = debug_info()->create_scope_values(exparray);
 966     DebugToken *monvals = debug_info()->create_monitor_values(monarray);
 967 
 968     // Make method available for all Safepoints
 969     ciMethod* scope_method = method ? method : _method;
 970     // Describe the scope here
 971     assert(jvms->bci() >= InvocationEntryBci && jvms->bci() <= 0x10000, "must be a valid or entry BCI");
 972     assert(!jvms->should_reexecute() || depth == max_depth, "reexecute allowed only for the youngest");
 973     // Now we can describe the scope.
 974     debug_info()->describe_scope(safepoint_pc_offset, scope_method, jvms->bci(), jvms->should_reexecute(), is_method_handle_invoke, return_oop, locvals, expvals, monvals);
 975   } // End jvms loop
 976 
 977   // Mark the end of the scope set.
 978   debug_info()->end_safepoint(safepoint_pc_offset);
 979 }
 980 
 981 
 982 
 983 // A simplified version of Process_OopMap_Node, to handle non-safepoints.
 984 class NonSafepointEmitter {
 985   Compile*  C;
 986   JVMState* _pending_jvms;
 987   int       _pending_offset;
 988 
 989   void emit_non_safepoint();
 990 
 991  public:
 992   NonSafepointEmitter(Compile* compile) {
 993     this->C = compile;
 994     _pending_jvms = NULL;
 995     _pending_offset = 0;
 996   }
 997 
 998   void observe_instruction(Node* n, int pc_offset) {
 999     if (!C->debug_info()->recording_non_safepoints())  return;
1000 
1001     Node_Notes* nn = C->node_notes_at(n->_idx);
1002     if (nn == NULL || nn->jvms() == NULL)  return;
1003     if (_pending_jvms != NULL &&
1004         _pending_jvms->same_calls_as(nn->jvms())) {
1005       // Repeated JVMS?  Stretch it up here.
1006       _pending_offset = pc_offset;
1007     } else {
1008       if (_pending_jvms != NULL &&
1009           _pending_offset < pc_offset) {
1010         emit_non_safepoint();
1011       }
1012       _pending_jvms = NULL;
1013       if (pc_offset > C->debug_info()->last_pc_offset()) {
1014         // This is the only way _pending_jvms can become non-NULL:
1015         _pending_jvms = nn->jvms();
1016         _pending_offset = pc_offset;
1017       }
1018     }
1019   }
1020 
1021   // Stay out of the way of real safepoints:
1022   void observe_safepoint(JVMState* jvms, int pc_offset) {
1023     if (_pending_jvms != NULL &&
1024         !_pending_jvms->same_calls_as(jvms) &&
1025         _pending_offset < pc_offset) {
1026       emit_non_safepoint();
1027     }
1028     _pending_jvms = NULL;
1029   }
1030 
1031   void flush_at_end() {
1032     if (_pending_jvms != NULL) {
1033       emit_non_safepoint();
1034     }
1035     _pending_jvms = NULL;
1036   }
1037 };
1038 
1039 void NonSafepointEmitter::emit_non_safepoint() {
1040   JVMState* youngest_jvms = _pending_jvms;
1041   int       pc_offset     = _pending_offset;
1042 
1043   // Clear it now:
1044   _pending_jvms = NULL;
1045 
1046   DebugInformationRecorder* debug_info = C->debug_info();
1047   assert(debug_info->recording_non_safepoints(), "sanity");
1048 
1049   debug_info->add_non_safepoint(pc_offset);
1050   int max_depth = youngest_jvms->depth();
1051 
1052   // Visit scopes from oldest to youngest.
1053   for (int depth = 1; depth <= max_depth; depth++) {
1054     JVMState* jvms = youngest_jvms->of_depth(depth);
1055     ciMethod* method = jvms->has_method() ? jvms->method() : NULL;
1056     assert(!jvms->should_reexecute() || depth==max_depth, "reexecute allowed only for the youngest");
1057     debug_info->describe_scope(pc_offset, method, jvms->bci(), jvms->should_reexecute());
1058   }
1059 
1060   // Mark the end of the scope set.
1061   debug_info->end_non_safepoint(pc_offset);
1062 }
1063 
1064 //------------------------------init_buffer------------------------------------
1065 CodeBuffer* Compile::init_buffer(uint* blk_starts) {
1066 
1067   // Set the initially allocated size
1068   int  code_req   = initial_code_capacity;
1069   int  locs_req   = initial_locs_capacity;
1070   int  stub_req   = TraceJumps ? initial_stub_capacity * 10 : initial_stub_capacity;
1071   int  const_req  = initial_const_capacity;
1072 
1073   int  pad_req    = NativeCall::instruction_size;
1074   // The extra spacing after the code is necessary on some platforms.
1075   // Sometimes we need to patch in a jump after the last instruction,
1076   // if the nmethod has been deoptimized.  (See 4932387, 4894843.)
1077 
1078   // Compute the byte offset where we can store the deopt pc.
1079   if (fixed_slots() != 0) {
1080     _orig_pc_slot_offset_in_bytes = _regalloc->reg2offset(OptoReg::stack2reg(_orig_pc_slot));
1081   }
1082 
1083   // Compute prolog code size
1084   _method_size = 0;
1085   _frame_slots = OptoReg::reg2stack(_matcher->_old_SP)+_regalloc->_framesize;
1086 #if defined(IA64) && !defined(AIX)
1087   if (save_argument_registers()) {
1088     // 4815101: this is a stub with implicit and unknown precision fp args.
1089     // The usual spill mechanism can only generate stfd's in this case, which
1090     // doesn't work if the fp reg to spill contains a single-precision denorm.
1091     // Instead, we hack around the normal spill mechanism using stfspill's and
1092     // ldffill's in the MachProlog and MachEpilog emit methods.  We allocate
1093     // space here for the fp arg regs (f8-f15) we're going to thusly spill.
1094     //
1095     // If we ever implement 16-byte 'registers' == stack slots, we can
1096     // get rid of this hack and have SpillCopy generate stfspill/ldffill
1097     // instead of stfd/stfs/ldfd/ldfs.
1098     _frame_slots += 8*(16/BytesPerInt);
1099   }
1100 #endif
1101   assert(_frame_slots >= 0 && _frame_slots < 1000000, "sanity check");
1102 
1103   if (has_mach_constant_base_node()) {
1104     uint add_size = 0;
1105     // Fill the constant table.
1106     // Note:  This must happen before shorten_branches.
1107     for (uint i = 0; i < _cfg->number_of_blocks(); i++) {
1108       Block* b = _cfg->get_block(i);
1109 
1110       for (uint j = 0; j < b->number_of_nodes(); j++) {
1111         Node* n = b->get_node(j);
1112 
1113         // If the node is a MachConstantNode evaluate the constant
1114         // value section.
1115         if (n->is_MachConstant()) {
1116           MachConstantNode* machcon = n->as_MachConstant();
1117           machcon->eval_constant(C);
1118         } else if (n->is_Mach()) {
1119           // On Power there are more nodes that issue constants.
1120           add_size += (n->as_Mach()->ins_num_consts() * 8);
1121         }
1122       }
1123     }
1124 
1125     // Calculate the offsets of the constants and the size of the
1126     // constant table (including the padding to the next section).
1127     constant_table().calculate_offsets_and_size();
1128     const_req = constant_table().size() + add_size;
1129   }
1130 
1131   // Initialize the space for the BufferBlob used to find and verify
1132   // instruction size in MachNode::emit_size()
1133   init_scratch_buffer_blob(const_req);
1134   if (failing())  return NULL; // Out of memory
1135 
1136   // Pre-compute the length of blocks and replace
1137   // long branches with short if machine supports it.
1138   shorten_branches(blk_starts, code_req, locs_req, stub_req);
1139 
1140   // nmethod and CodeBuffer count stubs & constants as part of method's code.
1141   // class HandlerImpl is platform-specific and defined in the *.ad files.
1142   int exception_handler_req = HandlerImpl::size_exception_handler() + MAX_stubs_size; // add marginal slop for handler
1143   int deopt_handler_req     = HandlerImpl::size_deopt_handler()     + MAX_stubs_size; // add marginal slop for handler
1144   stub_req += MAX_stubs_size;   // ensure per-stub margin
1145   code_req += MAX_inst_size;    // ensure per-instruction margin
1146 
1147   if (StressCodeBuffers)
1148     code_req = const_req = stub_req = exception_handler_req = deopt_handler_req = 0x10;  // force expansion
1149 
1150   int total_req =
1151     const_req +
1152     code_req +
1153     pad_req +
1154     stub_req +
1155     exception_handler_req +
1156     deopt_handler_req;               // deopt handler
1157 
1158   if (has_method_handle_invokes())
1159     total_req += deopt_handler_req;  // deopt MH handler
1160 
1161   CodeBuffer* cb = code_buffer();
1162   cb->initialize(total_req, locs_req);
1163 
1164   // Have we run out of code space?
1165   if ((cb->blob() == NULL) || (!CompileBroker::should_compile_new_jobs())) {
1166     C->record_failure("CodeCache is full");
1167     return NULL;
1168   }
1169   // Configure the code buffer.
1170   cb->initialize_consts_size(const_req);
1171   cb->initialize_stubs_size(stub_req);
1172   cb->initialize_oop_recorder(env()->oop_recorder());
1173 
1174   // fill in the nop array for bundling computations
1175   MachNode *_nop_list[Bundle::_nop_count];
1176   Bundle::initialize_nops(_nop_list, this);
1177 
1178   return cb;
1179 }
1180 
1181 //------------------------------fill_buffer------------------------------------
1182 void Compile::fill_buffer(CodeBuffer* cb, uint* blk_starts) {
1183   // blk_starts[] contains offsets calculated during short branches processing,
1184   // offsets should not be increased during following steps.
1185 
1186   // Compute the size of first NumberOfLoopInstrToAlign instructions at head
1187   // of a loop. It is used to determine the padding for loop alignment.
1188   compute_loop_first_inst_sizes();
1189 
1190   // Create oopmap set.
1191   _oop_map_set = new OopMapSet();
1192 
1193   // !!!!! This preserves old handling of oopmaps for now
1194   debug_info()->set_oopmaps(_oop_map_set);
1195 
1196   uint nblocks  = _cfg->number_of_blocks();
1197   // Count and start of implicit null check instructions
1198   uint inct_cnt = 0;
1199   uint *inct_starts = NEW_RESOURCE_ARRAY(uint, nblocks+1);
1200 
1201   // Count and start of calls
1202   uint *call_returns = NEW_RESOURCE_ARRAY(uint, nblocks+1);
1203 
1204   uint  return_offset = 0;
1205   int nop_size = (new (this) MachNopNode())->size(_regalloc);
1206 
1207   int previous_offset = 0;
1208   int current_offset  = 0;
1209   int last_call_offset = -1;
1210   int last_avoid_back_to_back_offset = -1;
1211 #ifdef ASSERT
1212   uint* jmp_target = NEW_RESOURCE_ARRAY(uint,nblocks);
1213   uint* jmp_offset = NEW_RESOURCE_ARRAY(uint,nblocks);
1214   uint* jmp_size   = NEW_RESOURCE_ARRAY(uint,nblocks);
1215   uint* jmp_rule   = NEW_RESOURCE_ARRAY(uint,nblocks);
1216 #endif
1217 
1218   // Create an array of unused labels, one for each basic block, if printing is enabled
1219 #ifndef PRODUCT
1220   int *node_offsets      = NULL;
1221   uint node_offset_limit = unique();
1222 
1223   if (print_assembly())
1224     node_offsets         = NEW_RESOURCE_ARRAY(int, node_offset_limit);
1225 #endif
1226 
1227   NonSafepointEmitter non_safepoints(this);  // emit non-safepoints lazily
1228 
1229   // Emit the constant table.
1230   if (has_mach_constant_base_node()) {
1231     constant_table().emit(*cb);
1232   }
1233 
1234   // Create an array of labels, one for each basic block
1235   Label *blk_labels = NEW_RESOURCE_ARRAY(Label, nblocks+1);
1236   for (uint i=0; i <= nblocks; i++) {
1237     blk_labels[i].init();
1238   }
1239 
1240   // ------------------
1241   // Now fill in the code buffer
1242   Node *delay_slot = NULL;
1243 
1244   for (uint i = 0; i < nblocks; i++) {
1245     Block* block = _cfg->get_block(i);
1246     Node* head = block->head();
1247 
1248     // If this block needs to start aligned (i.e, can be reached other
1249     // than by falling-thru from the previous block), then force the
1250     // start of a new bundle.
1251     if (Pipeline::requires_bundling() && starts_bundle(head)) {
1252       cb->flush_bundle(true);
1253     }
1254 
1255 #ifdef ASSERT
1256     if (!block->is_connector()) {
1257       stringStream st;
1258       block->dump_head(_cfg, &st);
1259       MacroAssembler(cb).block_comment(st.as_string());
1260     }
1261     jmp_target[i] = 0;
1262     jmp_offset[i] = 0;
1263     jmp_size[i]   = 0;
1264     jmp_rule[i]   = 0;
1265 #endif
1266     int blk_offset = current_offset;
1267 
1268     // Define the label at the beginning of the basic block
1269     MacroAssembler(cb).bind(blk_labels[block->_pre_order]);
1270 
1271     uint last_inst = block->number_of_nodes();
1272 
1273     // Emit block normally, except for last instruction.
1274     // Emit means "dump code bits into code buffer".
1275     for (uint j = 0; j<last_inst; j++) {
1276 
1277       // Get the node
1278       Node* n = block->get_node(j);
1279 
1280       // See if delay slots are supported
1281       if (valid_bundle_info(n) &&
1282           node_bundling(n)->used_in_unconditional_delay()) {
1283         assert(delay_slot == NULL, "no use of delay slot node");
1284         assert(n->size(_regalloc) == Pipeline::instr_unit_size(), "delay slot instruction wrong size");
1285 
1286         delay_slot = n;
1287         continue;
1288       }
1289 
1290       // If this starts a new instruction group, then flush the current one
1291       // (but allow split bundles)
1292       if (Pipeline::requires_bundling() && starts_bundle(n))
1293         cb->flush_bundle(false);
1294 
1295       // The following logic is duplicated in the code ifdeffed for
1296       // ENABLE_ZAP_DEAD_LOCALS which appears above in this file.  It
1297       // should be factored out.  Or maybe dispersed to the nodes?
1298 
1299       // Special handling for SafePoint/Call Nodes
1300       bool is_mcall = false;
1301       if (n->is_Mach()) {
1302         MachNode *mach = n->as_Mach();
1303         is_mcall = n->is_MachCall();
1304         bool is_sfn = n->is_MachSafePoint();
1305 
1306         // If this requires all previous instructions be flushed, then do so
1307         if (is_sfn || is_mcall || mach->alignment_required() != 1) {
1308           cb->flush_bundle(true);
1309           current_offset = cb->insts_size();
1310         }
1311 
1312         // A padding may be needed again since a previous instruction
1313         // could be moved to delay slot.
1314 
1315         // align the instruction if necessary
1316         int padding = mach->compute_padding(current_offset);
1317         // Make sure safepoint node for polling is distinct from a call's
1318         // return by adding a nop if needed.
1319         if (is_sfn && !is_mcall && padding == 0 && current_offset == last_call_offset) {
1320           padding = nop_size;
1321         }
1322         if (padding == 0 && mach->avoid_back_to_back(MachNode::AVOID_BEFORE) &&
1323             current_offset == last_avoid_back_to_back_offset) {
1324           // Avoid back to back some instructions.
1325           padding = nop_size;
1326         }
1327 
1328         if(padding > 0) {
1329           assert((padding % nop_size) == 0, "padding is not a multiple of NOP size");
1330           int nops_cnt = padding / nop_size;
1331           MachNode *nop = new (this) MachNopNode(nops_cnt);
1332           block->insert_node(nop, j++);
1333           last_inst++;
1334           _cfg->map_node_to_block(nop, block);
1335           nop->emit(*cb, _regalloc);
1336           cb->flush_bundle(true);
1337           current_offset = cb->insts_size();
1338         }
1339 
1340         // Remember the start of the last call in a basic block
1341         if (is_mcall) {
1342           MachCallNode *mcall = mach->as_MachCall();
1343 
1344           // This destination address is NOT PC-relative
1345           mcall->method_set((intptr_t)mcall->entry_point());
1346 
1347           // Save the return address
1348           call_returns[block->_pre_order] = current_offset + mcall->ret_addr_offset();
1349 
1350           if (mcall->is_MachCallLeaf()) {
1351             is_mcall = false;
1352             is_sfn = false;
1353           }
1354         }
1355 
1356         // sfn will be valid whenever mcall is valid now because of inheritance
1357         if (is_sfn || is_mcall) {
1358 
1359           // Handle special safepoint nodes for synchronization
1360           if (!is_mcall) {
1361             MachSafePointNode *sfn = mach->as_MachSafePoint();
1362             // !!!!! Stubs only need an oopmap right now, so bail out
1363             if (sfn->jvms()->method() == NULL) {
1364               // Write the oopmap directly to the code blob??!!
1365 #             ifdef ENABLE_ZAP_DEAD_LOCALS
1366               assert( !is_node_getting_a_safepoint(sfn),  "logic does not match; false positive");
1367 #             endif
1368               continue;
1369             }
1370           } // End synchronization
1371 
1372           non_safepoints.observe_safepoint(mach->as_MachSafePoint()->jvms(),
1373                                            current_offset);
1374           Process_OopMap_Node(mach, current_offset);
1375         } // End if safepoint
1376 
1377         // If this is a null check, then add the start of the previous instruction to the list
1378         else if( mach->is_MachNullCheck() ) {
1379           inct_starts[inct_cnt++] = previous_offset;
1380         }
1381 
1382         // If this is a branch, then fill in the label with the target BB's label
1383         else if (mach->is_MachBranch()) {
1384           // This requires the TRUE branch target be in succs[0]
1385           uint block_num = block->non_connector_successor(0)->_pre_order;
1386 
1387           // Try to replace long branch if delay slot is not used,
1388           // it is mostly for back branches since forward branch's
1389           // distance is not updated yet.
1390           bool delay_slot_is_used = valid_bundle_info(n) &&
1391                                     node_bundling(n)->use_unconditional_delay();
1392           if (!delay_slot_is_used && mach->may_be_short_branch()) {
1393            assert(delay_slot == NULL, "not expecting delay slot node");
1394            int br_size = n->size(_regalloc);
1395             int offset = blk_starts[block_num] - current_offset;
1396             if (block_num >= i) {
1397               // Current and following block's offset are not
1398               // finalized yet, adjust distance by the difference
1399               // between calculated and final offsets of current block.
1400               offset -= (blk_starts[i] - blk_offset);
1401             }
1402             // In the following code a nop could be inserted before
1403             // the branch which will increase the backward distance.
1404             bool needs_padding = (current_offset == last_avoid_back_to_back_offset);
1405             if (needs_padding && offset <= 0)
1406               offset -= nop_size;
1407 
1408             if (_matcher->is_short_branch_offset(mach->rule(), br_size, offset)) {
1409               // We've got a winner.  Replace this branch.
1410               MachNode* replacement = mach->as_MachBranch()->short_branch_version(this);
1411 
1412               // Update the jmp_size.
1413               int new_size = replacement->size(_regalloc);
1414               assert((br_size - new_size) >= (int)nop_size, "short_branch size should be smaller");
1415               // Insert padding between avoid_back_to_back branches.
1416               if (needs_padding && replacement->avoid_back_to_back(MachNode::AVOID_BEFORE)) {
1417                 MachNode *nop = new (this) MachNopNode();
1418                 block->insert_node(nop, j++);
1419                 _cfg->map_node_to_block(nop, block);
1420                 last_inst++;
1421                 nop->emit(*cb, _regalloc);
1422                 cb->flush_bundle(true);
1423                 current_offset = cb->insts_size();
1424               }
1425 #ifdef ASSERT
1426               jmp_target[i] = block_num;
1427               jmp_offset[i] = current_offset - blk_offset;
1428               jmp_size[i]   = new_size;
1429               jmp_rule[i]   = mach->rule();
1430 #endif
1431               block->map_node(replacement, j);
1432               mach->subsume_by(replacement, C);
1433               n    = replacement;
1434               mach = replacement;
1435             }
1436           }
1437           mach->as_MachBranch()->label_set( &blk_labels[block_num], block_num );
1438         } else if (mach->ideal_Opcode() == Op_Jump) {
1439           for (uint h = 0; h < block->_num_succs; h++) {
1440             Block* succs_block = block->_succs[h];
1441             for (uint j = 1; j < succs_block->num_preds(); j++) {
1442               Node* jpn = succs_block->pred(j);
1443               if (jpn->is_JumpProj() && jpn->in(0) == mach) {
1444                 uint block_num = succs_block->non_connector()->_pre_order;
1445                 Label *blkLabel = &blk_labels[block_num];
1446                 mach->add_case_label(jpn->as_JumpProj()->proj_no(), blkLabel);
1447               }
1448             }
1449           }
1450         }
1451 #ifdef ASSERT
1452         // Check that oop-store precedes the card-mark
1453         else if (mach->ideal_Opcode() == Op_StoreCM) {
1454           uint storeCM_idx = j;
1455           int count = 0;
1456           for (uint prec = mach->req(); prec < mach->len(); prec++) {
1457             Node *oop_store = mach->in(prec);  // Precedence edge
1458             if (oop_store == NULL) continue;
1459             count++;
1460             uint i4;
1461             for (i4 = 0; i4 < last_inst; ++i4) {
1462               if (block->get_node(i4) == oop_store) {
1463                 break;
1464               }
1465             }
1466             // Note: This test can provide a false failure if other precedence
1467             // edges have been added to the storeCMNode.
1468             assert(i4 == last_inst || i4 < storeCM_idx, "CM card-mark executes before oop-store");
1469           }
1470           assert(count > 0, "storeCM expects at least one precedence edge");
1471         }
1472 #endif
1473         else if (!n->is_Proj()) {
1474           // Remember the beginning of the previous instruction, in case
1475           // it's followed by a flag-kill and a null-check.  Happens on
1476           // Intel all the time, with add-to-memory kind of opcodes.
1477           previous_offset = current_offset;
1478         }
1479 
1480         // Not an else-if!
1481         // If this is a trap based cmp then add its offset to the list.
1482         if (mach->is_TrapBasedCheckNode()) {
1483           inct_starts[inct_cnt++] = current_offset;
1484         }
1485       }
1486 
1487       // Verify that there is sufficient space remaining
1488       cb->insts()->maybe_expand_to_ensure_remaining(MAX_inst_size);
1489       if ((cb->blob() == NULL) || (!CompileBroker::should_compile_new_jobs())) {
1490         C->record_failure("CodeCache is full");
1491         return;
1492       }
1493 
1494       // Save the offset for the listing
1495 #ifndef PRODUCT
1496       if (node_offsets && n->_idx < node_offset_limit)
1497         node_offsets[n->_idx] = cb->insts_size();
1498 #endif
1499 
1500       // "Normal" instruction case
1501       DEBUG_ONLY( uint instr_offset = cb->insts_size(); )
1502       n->emit(*cb, _regalloc);
1503       current_offset  = cb->insts_size();
1504 
1505       // Above we only verified that there is enough space in the instruction section.
1506       // However, the instruction may emit stubs that cause code buffer expansion.
1507       // Bail out here if expansion failed due to a lack of code cache space.
1508       if (failing()) {
1509         return;
1510       }
1511 
1512 #ifdef ASSERT
1513       if (n->size(_regalloc) < (current_offset-instr_offset)) {
1514         n->dump();
1515         assert(false, "wrong size of mach node");
1516       }
1517 #endif
1518       non_safepoints.observe_instruction(n, current_offset);
1519 
1520       // mcall is last "call" that can be a safepoint
1521       // record it so we can see if a poll will directly follow it
1522       // in which case we'll need a pad to make the PcDesc sites unique
1523       // see  5010568. This can be slightly inaccurate but conservative
1524       // in the case that return address is not actually at current_offset.
1525       // This is a small price to pay.
1526 
1527       if (is_mcall) {
1528         last_call_offset = current_offset;
1529       }
1530 
1531       if (n->is_Mach() && n->as_Mach()->avoid_back_to_back(MachNode::AVOID_AFTER)) {
1532         // Avoid back to back some instructions.
1533         last_avoid_back_to_back_offset = current_offset;
1534       }
1535 
1536       // See if this instruction has a delay slot
1537       if (valid_bundle_info(n) && node_bundling(n)->use_unconditional_delay()) {
1538         assert(delay_slot != NULL, "expecting delay slot node");
1539 
1540         // Back up 1 instruction
1541         cb->set_insts_end(cb->insts_end() - Pipeline::instr_unit_size());
1542 
1543         // Save the offset for the listing
1544 #ifndef PRODUCT
1545         if (node_offsets && delay_slot->_idx < node_offset_limit)
1546           node_offsets[delay_slot->_idx] = cb->insts_size();
1547 #endif
1548 
1549         // Support a SafePoint in the delay slot
1550         if (delay_slot->is_MachSafePoint()) {
1551           MachNode *mach = delay_slot->as_Mach();
1552           // !!!!! Stubs only need an oopmap right now, so bail out
1553           if (!mach->is_MachCall() && mach->as_MachSafePoint()->jvms()->method() == NULL) {
1554             // Write the oopmap directly to the code blob??!!
1555 #           ifdef ENABLE_ZAP_DEAD_LOCALS
1556             assert( !is_node_getting_a_safepoint(mach),  "logic does not match; false positive");
1557 #           endif
1558             delay_slot = NULL;
1559             continue;
1560           }
1561 
1562           int adjusted_offset = current_offset - Pipeline::instr_unit_size();
1563           non_safepoints.observe_safepoint(mach->as_MachSafePoint()->jvms(),
1564                                            adjusted_offset);
1565           // Generate an OopMap entry
1566           Process_OopMap_Node(mach, adjusted_offset);
1567         }
1568 
1569         // Insert the delay slot instruction
1570         delay_slot->emit(*cb, _regalloc);
1571 
1572         // Don't reuse it
1573         delay_slot = NULL;
1574       }
1575 
1576     } // End for all instructions in block
1577 
1578     // If the next block is the top of a loop, pad this block out to align
1579     // the loop top a little. Helps prevent pipe stalls at loop back branches.
1580     if (i < nblocks-1) {
1581       Block *nb = _cfg->get_block(i + 1);
1582       int padding = nb->alignment_padding(current_offset);
1583       if( padding > 0 ) {
1584         MachNode *nop = new (this) MachNopNode(padding / nop_size);
1585         block->insert_node(nop, block->number_of_nodes());
1586         _cfg->map_node_to_block(nop, block);
1587         nop->emit(*cb, _regalloc);
1588         current_offset = cb->insts_size();
1589       }
1590     }
1591     // Verify that the distance for generated before forward
1592     // short branches is still valid.
1593     guarantee((int)(blk_starts[i+1] - blk_starts[i]) >= (current_offset - blk_offset), "shouldn't increase block size");
1594 
1595     // Save new block start offset
1596     blk_starts[i] = blk_offset;
1597   } // End of for all blocks
1598   blk_starts[nblocks] = current_offset;
1599 
1600   non_safepoints.flush_at_end();
1601 
1602   // Offset too large?
1603   if (failing())  return;
1604 
1605   // Define a pseudo-label at the end of the code
1606   MacroAssembler(cb).bind( blk_labels[nblocks] );
1607 
1608   // Compute the size of the first block
1609   _first_block_size = blk_labels[1].loc_pos() - blk_labels[0].loc_pos();
1610 
1611   assert(cb->insts_size() < 500000, "method is unreasonably large");
1612 
1613 #ifdef ASSERT
1614   for (uint i = 0; i < nblocks; i++) { // For all blocks
1615     if (jmp_target[i] != 0) {
1616       int br_size = jmp_size[i];
1617       int offset = blk_starts[jmp_target[i]]-(blk_starts[i] + jmp_offset[i]);
1618       if (!_matcher->is_short_branch_offset(jmp_rule[i], br_size, offset)) {
1619         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]);
1620         assert(false, "Displacement too large for short jmp");
1621       }
1622     }
1623   }
1624 #endif
1625 
1626 #ifndef PRODUCT
1627   // Information on the size of the method, without the extraneous code
1628   Scheduling::increment_method_size(cb->insts_size());
1629 #endif
1630 
1631   // ------------------
1632   // Fill in exception table entries.
1633   FillExceptionTables(inct_cnt, call_returns, inct_starts, blk_labels);
1634 
1635   // Only java methods have exception handlers and deopt handlers
1636   // class HandlerImpl is platform-specific and defined in the *.ad files.
1637   if (_method) {
1638     // Emit the exception handler code.
1639     _code_offsets.set_value(CodeOffsets::Exceptions, HandlerImpl::emit_exception_handler(*cb));
1640     if (failing()) {
1641       return; // CodeBuffer::expand failed
1642     }
1643     // Emit the deopt handler code.
1644     _code_offsets.set_value(CodeOffsets::Deopt, HandlerImpl::emit_deopt_handler(*cb));
1645 
1646     // Emit the MethodHandle deopt handler code (if required).
1647     if (has_method_handle_invokes() && !failing()) {
1648       // We can use the same code as for the normal deopt handler, we
1649       // just need a different entry point address.
1650       _code_offsets.set_value(CodeOffsets::DeoptMH, HandlerImpl::emit_deopt_handler(*cb));
1651     }
1652   }
1653 
1654   // One last check for failed CodeBuffer::expand:
1655   if ((cb->blob() == NULL) || (!CompileBroker::should_compile_new_jobs())) {
1656     C->record_failure("CodeCache is full");
1657     return;
1658   }
1659 
1660 #ifndef PRODUCT
1661   // Dump the assembly code, including basic-block numbers
1662   if (print_assembly()) {
1663     ttyLocker ttyl;  // keep the following output all in one block
1664     if (!VMThread::should_terminate()) {  // test this under the tty lock
1665       // This output goes directly to the tty, not the compiler log.
1666       // To enable tools to match it up with the compilation activity,
1667       // be sure to tag this tty output with the compile ID.
1668       if (xtty != NULL) {
1669         xtty->head("opto_assembly compile_id='%d'%s", compile_id(),
1670                    is_osr_compilation()    ? " compile_kind='osr'" :
1671                    "");
1672       }
1673       if (method() != NULL) {
1674         method()->print_metadata();
1675       }
1676       dump_asm(node_offsets, node_offset_limit);
1677       if (xtty != NULL) {
1678         xtty->tail("opto_assembly");
1679       }
1680     }
1681   }
1682 #endif
1683 
1684 }
1685 
1686 void Compile::FillExceptionTables(uint cnt, uint *call_returns, uint *inct_starts, Label *blk_labels) {
1687   _inc_table.set_size(cnt);
1688 
1689   uint inct_cnt = 0;
1690   for (uint i = 0; i < _cfg->number_of_blocks(); i++) {
1691     Block* block = _cfg->get_block(i);
1692     Node *n = NULL;
1693     int j;
1694 
1695     // Find the branch; ignore trailing NOPs.
1696     for (j = block->number_of_nodes() - 1; j >= 0; j--) {
1697       n = block->get_node(j);
1698       if (!n->is_Mach() || n->as_Mach()->ideal_Opcode() != Op_Con) {
1699         break;
1700       }
1701     }
1702 
1703     // If we didn't find anything, continue
1704     if (j < 0) {
1705       continue;
1706     }
1707 
1708     // Compute ExceptionHandlerTable subtable entry and add it
1709     // (skip empty blocks)
1710     if (n->is_Catch()) {
1711 
1712       // Get the offset of the return from the call
1713       uint call_return = call_returns[block->_pre_order];
1714 #ifdef ASSERT
1715       assert( call_return > 0, "no call seen for this basic block" );
1716       while (block->get_node(--j)->is_MachProj()) ;
1717       assert(block->get_node(j)->is_MachCall(), "CatchProj must follow call");
1718 #endif
1719       // last instruction is a CatchNode, find it's CatchProjNodes
1720       int nof_succs = block->_num_succs;
1721       // allocate space
1722       GrowableArray<intptr_t> handler_bcis(nof_succs);
1723       GrowableArray<intptr_t> handler_pcos(nof_succs);
1724       // iterate through all successors
1725       for (int j = 0; j < nof_succs; j++) {
1726         Block* s = block->_succs[j];
1727         bool found_p = false;
1728         for (uint k = 1; k < s->num_preds(); k++) {
1729           Node* pk = s->pred(k);
1730           if (pk->is_CatchProj() && pk->in(0) == n) {
1731             const CatchProjNode* p = pk->as_CatchProj();
1732             found_p = true;
1733             // add the corresponding handler bci & pco information
1734             if (p->_con != CatchProjNode::fall_through_index) {
1735               // p leads to an exception handler (and is not fall through)
1736               assert(s == _cfg->get_block(s->_pre_order), "bad numbering");
1737               // no duplicates, please
1738               if (!handler_bcis.contains(p->handler_bci())) {
1739                 uint block_num = s->non_connector()->_pre_order;
1740                 handler_bcis.append(p->handler_bci());
1741                 handler_pcos.append(blk_labels[block_num].loc_pos());
1742               }
1743             }
1744           }
1745         }
1746         assert(found_p, "no matching predecessor found");
1747         // Note:  Due to empty block removal, one block may have
1748         // several CatchProj inputs, from the same Catch.
1749       }
1750 
1751       // Set the offset of the return from the call
1752       _handler_table.add_subtable(call_return, &handler_bcis, NULL, &handler_pcos);
1753       continue;
1754     }
1755 
1756     // Handle implicit null exception table updates
1757     if (n->is_MachNullCheck()) {
1758       uint block_num = block->non_connector_successor(0)->_pre_order;
1759       _inc_table.append(inct_starts[inct_cnt++], blk_labels[block_num].loc_pos());
1760       continue;
1761     }
1762     // Handle implicit exception table updates: trap instructions.
1763     if (n->is_Mach() && n->as_Mach()->is_TrapBasedCheckNode()) {
1764       uint block_num = block->non_connector_successor(0)->_pre_order;
1765       _inc_table.append(inct_starts[inct_cnt++], blk_labels[block_num].loc_pos());
1766       continue;
1767     }
1768   } // End of for all blocks fill in exception table entries
1769 }
1770 
1771 // Static Variables
1772 #ifndef PRODUCT
1773 uint Scheduling::_total_nop_size = 0;
1774 uint Scheduling::_total_method_size = 0;
1775 uint Scheduling::_total_branches = 0;
1776 uint Scheduling::_total_unconditional_delays = 0;
1777 uint Scheduling::_total_instructions_per_bundle[Pipeline::_max_instrs_per_cycle+1];
1778 #endif
1779 
1780 // Initializer for class Scheduling
1781 
1782 Scheduling::Scheduling(Arena *arena, Compile &compile)
1783   : _arena(arena),
1784     _cfg(compile.cfg()),
1785     _regalloc(compile.regalloc()),
1786     _reg_node(arena),
1787     _bundle_instr_count(0),
1788     _bundle_cycle_number(0),
1789     _scheduled(arena),
1790     _available(arena),
1791     _next_node(NULL),
1792     _bundle_use(0, 0, resource_count, &_bundle_use_elements[0]),
1793     _pinch_free_list(arena)
1794 #ifndef PRODUCT
1795   , _branches(0)
1796   , _unconditional_delays(0)
1797 #endif
1798 {
1799   // Create a MachNopNode
1800   _nop = new (&compile) MachNopNode();
1801 
1802   // Now that the nops are in the array, save the count
1803   // (but allow entries for the nops)
1804   _node_bundling_limit = compile.unique();
1805   uint node_max = _regalloc->node_regs_max_index();
1806 
1807   compile.set_node_bundling_limit(_node_bundling_limit);
1808 
1809   // This one is persistent within the Compile class
1810   _node_bundling_base = NEW_ARENA_ARRAY(compile.comp_arena(), Bundle, node_max);
1811 
1812   // Allocate space for fixed-size arrays
1813   _node_latency    = NEW_ARENA_ARRAY(arena, unsigned short, node_max);
1814   _uses            = NEW_ARENA_ARRAY(arena, short,          node_max);
1815   _current_latency = NEW_ARENA_ARRAY(arena, unsigned short, node_max);
1816 
1817   // Clear the arrays
1818   memset(_node_bundling_base, 0, node_max * sizeof(Bundle));
1819   memset(_node_latency,       0, node_max * sizeof(unsigned short));
1820   memset(_uses,               0, node_max * sizeof(short));
1821   memset(_current_latency,    0, node_max * sizeof(unsigned short));
1822 
1823   // Clear the bundling information
1824   memcpy(_bundle_use_elements, Pipeline_Use::elaborated_elements, sizeof(Pipeline_Use::elaborated_elements));
1825 
1826   // Get the last node
1827   Block* block = _cfg->get_block(_cfg->number_of_blocks() - 1);
1828 
1829   _next_node = block->get_node(block->number_of_nodes() - 1);
1830 }
1831 
1832 #ifndef PRODUCT
1833 // Scheduling destructor
1834 Scheduling::~Scheduling() {
1835   _total_branches             += _branches;
1836   _total_unconditional_delays += _unconditional_delays;
1837 }
1838 #endif
1839 
1840 // Step ahead "i" cycles
1841 void Scheduling::step(uint i) {
1842 
1843   Bundle *bundle = node_bundling(_next_node);
1844   bundle->set_starts_bundle();
1845 
1846   // Update the bundle record, but leave the flags information alone
1847   if (_bundle_instr_count > 0) {
1848     bundle->set_instr_count(_bundle_instr_count);
1849     bundle->set_resources_used(_bundle_use.resourcesUsed());
1850   }
1851 
1852   // Update the state information
1853   _bundle_instr_count = 0;
1854   _bundle_cycle_number += i;
1855   _bundle_use.step(i);
1856 }
1857 
1858 void Scheduling::step_and_clear() {
1859   Bundle *bundle = node_bundling(_next_node);
1860   bundle->set_starts_bundle();
1861 
1862   // Update the bundle record
1863   if (_bundle_instr_count > 0) {
1864     bundle->set_instr_count(_bundle_instr_count);
1865     bundle->set_resources_used(_bundle_use.resourcesUsed());
1866 
1867     _bundle_cycle_number += 1;
1868   }
1869 
1870   // Clear the bundling information
1871   _bundle_instr_count = 0;
1872   _bundle_use.reset();
1873 
1874   memcpy(_bundle_use_elements,
1875     Pipeline_Use::elaborated_elements,
1876     sizeof(Pipeline_Use::elaborated_elements));
1877 }
1878 
1879 // Perform instruction scheduling and bundling over the sequence of
1880 // instructions in backwards order.
1881 void Compile::ScheduleAndBundle() {
1882 
1883   // Don't optimize this if it isn't a method
1884   if (!_method)
1885     return;
1886 
1887   // Don't optimize this if scheduling is disabled
1888   if (!do_scheduling())
1889     return;
1890 
1891   // Scheduling code works only with pairs (8 bytes) maximum.
1892   if (max_vector_size() > 8)
1893     return;
1894 
1895   NOT_PRODUCT( TracePhase t2("isched", &_t_instrSched, TimeCompiler); )
1896 
1897   // Create a data structure for all the scheduling information
1898   Scheduling scheduling(Thread::current()->resource_area(), *this);
1899 
1900   // Walk backwards over each basic block, computing the needed alignment
1901   // Walk over all the basic blocks
1902   scheduling.DoScheduling();
1903 }
1904 
1905 // Compute the latency of all the instructions.  This is fairly simple,
1906 // because we already have a legal ordering.  Walk over the instructions
1907 // from first to last, and compute the latency of the instruction based
1908 // on the latency of the preceding instruction(s).
1909 void Scheduling::ComputeLocalLatenciesForward(const Block *bb) {
1910 #ifndef PRODUCT
1911   if (_cfg->C->trace_opto_output())
1912     tty->print("# -> ComputeLocalLatenciesForward\n");
1913 #endif
1914 
1915   // Walk over all the schedulable instructions
1916   for( uint j=_bb_start; j < _bb_end; j++ ) {
1917 
1918     // This is a kludge, forcing all latency calculations to start at 1.
1919     // Used to allow latency 0 to force an instruction to the beginning
1920     // of the bb
1921     uint latency = 1;
1922     Node *use = bb->get_node(j);
1923     uint nlen = use->len();
1924 
1925     // Walk over all the inputs
1926     for ( uint k=0; k < nlen; k++ ) {
1927       Node *def = use->in(k);
1928       if (!def)
1929         continue;
1930 
1931       uint l = _node_latency[def->_idx] + use->latency(k);
1932       if (latency < l)
1933         latency = l;
1934     }
1935 
1936     _node_latency[use->_idx] = latency;
1937 
1938 #ifndef PRODUCT
1939     if (_cfg->C->trace_opto_output()) {
1940       tty->print("# latency %4d: ", latency);
1941       use->dump();
1942     }
1943 #endif
1944   }
1945 
1946 #ifndef PRODUCT
1947   if (_cfg->C->trace_opto_output())
1948     tty->print("# <- ComputeLocalLatenciesForward\n");
1949 #endif
1950 
1951 } // end ComputeLocalLatenciesForward
1952 
1953 // See if this node fits into the present instruction bundle
1954 bool Scheduling::NodeFitsInBundle(Node *n) {
1955   uint n_idx = n->_idx;
1956 
1957   // If this is the unconditional delay instruction, then it fits
1958   if (n == _unconditional_delay_slot) {
1959 #ifndef PRODUCT
1960     if (_cfg->C->trace_opto_output())
1961       tty->print("#     NodeFitsInBundle [%4d]: TRUE; is in unconditional delay slot\n", n->_idx);
1962 #endif
1963     return (true);
1964   }
1965 
1966   // If the node cannot be scheduled this cycle, skip it
1967   if (_current_latency[n_idx] > _bundle_cycle_number) {
1968 #ifndef PRODUCT
1969     if (_cfg->C->trace_opto_output())
1970       tty->print("#     NodeFitsInBundle [%4d]: FALSE; latency %4d > %d\n",
1971         n->_idx, _current_latency[n_idx], _bundle_cycle_number);
1972 #endif
1973     return (false);
1974   }
1975 
1976   const Pipeline *node_pipeline = n->pipeline();
1977 
1978   uint instruction_count = node_pipeline->instructionCount();
1979   if (node_pipeline->mayHaveNoCode() && n->size(_regalloc) == 0)
1980     instruction_count = 0;
1981   else if (node_pipeline->hasBranchDelay() && !_unconditional_delay_slot)
1982     instruction_count++;
1983 
1984   if (_bundle_instr_count + instruction_count > Pipeline::_max_instrs_per_cycle) {
1985 #ifndef PRODUCT
1986     if (_cfg->C->trace_opto_output())
1987       tty->print("#     NodeFitsInBundle [%4d]: FALSE; too many instructions: %d > %d\n",
1988         n->_idx, _bundle_instr_count + instruction_count, Pipeline::_max_instrs_per_cycle);
1989 #endif
1990     return (false);
1991   }
1992 
1993   // Don't allow non-machine nodes to be handled this way
1994   if (!n->is_Mach() && instruction_count == 0)
1995     return (false);
1996 
1997   // See if there is any overlap
1998   uint delay = _bundle_use.full_latency(0, node_pipeline->resourceUse());
1999 
2000   if (delay > 0) {
2001 #ifndef PRODUCT
2002     if (_cfg->C->trace_opto_output())
2003       tty->print("#     NodeFitsInBundle [%4d]: FALSE; functional units overlap\n", n_idx);
2004 #endif
2005     return false;
2006   }
2007 
2008 #ifndef PRODUCT
2009   if (_cfg->C->trace_opto_output())
2010     tty->print("#     NodeFitsInBundle [%4d]:  TRUE\n", n_idx);
2011 #endif
2012 
2013   return true;
2014 }
2015 
2016 Node * Scheduling::ChooseNodeToBundle() {
2017   uint siz = _available.size();
2018 
2019   if (siz == 0) {
2020 
2021 #ifndef PRODUCT
2022     if (_cfg->C->trace_opto_output())
2023       tty->print("#   ChooseNodeToBundle: NULL\n");
2024 #endif
2025     return (NULL);
2026   }
2027 
2028   // Fast path, if only 1 instruction in the bundle
2029   if (siz == 1) {
2030 #ifndef PRODUCT
2031     if (_cfg->C->trace_opto_output()) {
2032       tty->print("#   ChooseNodeToBundle (only 1): ");
2033       _available[0]->dump();
2034     }
2035 #endif
2036     return (_available[0]);
2037   }
2038 
2039   // Don't bother, if the bundle is already full
2040   if (_bundle_instr_count < Pipeline::_max_instrs_per_cycle) {
2041     for ( uint i = 0; i < siz; i++ ) {
2042       Node *n = _available[i];
2043 
2044       // Skip projections, we'll handle them another way
2045       if (n->is_Proj())
2046         continue;
2047 
2048       // This presupposed that instructions are inserted into the
2049       // available list in a legality order; i.e. instructions that
2050       // must be inserted first are at the head of the list
2051       if (NodeFitsInBundle(n)) {
2052 #ifndef PRODUCT
2053         if (_cfg->C->trace_opto_output()) {
2054           tty->print("#   ChooseNodeToBundle: ");
2055           n->dump();
2056         }
2057 #endif
2058         return (n);
2059       }
2060     }
2061   }
2062 
2063   // Nothing fits in this bundle, choose the highest priority
2064 #ifndef PRODUCT
2065   if (_cfg->C->trace_opto_output()) {
2066     tty->print("#   ChooseNodeToBundle: ");
2067     _available[0]->dump();
2068   }
2069 #endif
2070 
2071   return _available[0];
2072 }
2073 
2074 void Scheduling::AddNodeToAvailableList(Node *n) {
2075   assert( !n->is_Proj(), "projections never directly made available" );
2076 #ifndef PRODUCT
2077   if (_cfg->C->trace_opto_output()) {
2078     tty->print("#   AddNodeToAvailableList: ");
2079     n->dump();
2080   }
2081 #endif
2082 
2083   int latency = _current_latency[n->_idx];
2084 
2085   // Insert in latency order (insertion sort)
2086   uint i;
2087   for ( i=0; i < _available.size(); i++ )
2088     if (_current_latency[_available[i]->_idx] > latency)
2089       break;
2090 
2091   // Special Check for compares following branches
2092   if( n->is_Mach() && _scheduled.size() > 0 ) {
2093     int op = n->as_Mach()->ideal_Opcode();
2094     Node *last = _scheduled[0];
2095     if( last->is_MachIf() && last->in(1) == n &&
2096         ( op == Op_CmpI ||
2097           op == Op_CmpU ||
2098           op == Op_CmpP ||
2099           op == Op_CmpF ||
2100           op == Op_CmpD ||
2101           op == Op_CmpL ) ) {
2102 
2103       // Recalculate position, moving to front of same latency
2104       for ( i=0 ; i < _available.size(); i++ )
2105         if (_current_latency[_available[i]->_idx] >= latency)
2106           break;
2107     }
2108   }
2109 
2110   // Insert the node in the available list
2111   _available.insert(i, n);
2112 
2113 #ifndef PRODUCT
2114   if (_cfg->C->trace_opto_output())
2115     dump_available();
2116 #endif
2117 }
2118 
2119 void Scheduling::DecrementUseCounts(Node *n, const Block *bb) {
2120   for ( uint i=0; i < n->len(); i++ ) {
2121     Node *def = n->in(i);
2122     if (!def) continue;
2123     if( def->is_Proj() )        // If this is a machine projection, then
2124       def = def->in(0);         // propagate usage thru to the base instruction
2125 
2126     if(_cfg->get_block_for_node(def) != bb) { // Ignore if not block-local
2127       continue;
2128     }
2129 
2130     // Compute the latency
2131     uint l = _bundle_cycle_number + n->latency(i);
2132     if (_current_latency[def->_idx] < l)
2133       _current_latency[def->_idx] = l;
2134 
2135     // If this does not have uses then schedule it
2136     if ((--_uses[def->_idx]) == 0)
2137       AddNodeToAvailableList(def);
2138   }
2139 }
2140 
2141 void Scheduling::AddNodeToBundle(Node *n, const Block *bb) {
2142 #ifndef PRODUCT
2143   if (_cfg->C->trace_opto_output()) {
2144     tty->print("#   AddNodeToBundle: ");
2145     n->dump();
2146   }
2147 #endif
2148 
2149   // Remove this from the available list
2150   uint i;
2151   for (i = 0; i < _available.size(); i++)
2152     if (_available[i] == n)
2153       break;
2154   assert(i < _available.size(), "entry in _available list not found");
2155   _available.remove(i);
2156 
2157   // See if this fits in the current bundle
2158   const Pipeline *node_pipeline = n->pipeline();
2159   const Pipeline_Use& node_usage = node_pipeline->resourceUse();
2160 
2161   // Check for instructions to be placed in the delay slot. We
2162   // do this before we actually schedule the current instruction,
2163   // because the delay slot follows the current instruction.
2164   if (Pipeline::_branch_has_delay_slot &&
2165       node_pipeline->hasBranchDelay() &&
2166       !_unconditional_delay_slot) {
2167 
2168     uint siz = _available.size();
2169 
2170     // Conditional branches can support an instruction that
2171     // is unconditionally executed and not dependent by the
2172     // branch, OR a conditionally executed instruction if
2173     // the branch is taken.  In practice, this means that
2174     // the first instruction at the branch target is
2175     // copied to the delay slot, and the branch goes to
2176     // the instruction after that at the branch target
2177     if ( n->is_MachBranch() ) {
2178 
2179       assert( !n->is_MachNullCheck(), "should not look for delay slot for Null Check" );
2180       assert( !n->is_Catch(),         "should not look for delay slot for Catch" );
2181 
2182 #ifndef PRODUCT
2183       _branches++;
2184 #endif
2185 
2186       // At least 1 instruction is on the available list
2187       // that is not dependent on the branch
2188       for (uint i = 0; i < siz; i++) {
2189         Node *d = _available[i];
2190         const Pipeline *avail_pipeline = d->pipeline();
2191 
2192         // Don't allow safepoints in the branch shadow, that will
2193         // cause a number of difficulties
2194         if ( avail_pipeline->instructionCount() == 1 &&
2195             !avail_pipeline->hasMultipleBundles() &&
2196             !avail_pipeline->hasBranchDelay() &&
2197             Pipeline::instr_has_unit_size() &&
2198             d->size(_regalloc) == Pipeline::instr_unit_size() &&
2199             NodeFitsInBundle(d) &&
2200             !node_bundling(d)->used_in_delay()) {
2201 
2202           if (d->is_Mach() && !d->is_MachSafePoint()) {
2203             // A node that fits in the delay slot was found, so we need to
2204             // set the appropriate bits in the bundle pipeline information so
2205             // that it correctly indicates resource usage.  Later, when we
2206             // attempt to add this instruction to the bundle, we will skip
2207             // setting the resource usage.
2208             _unconditional_delay_slot = d;
2209             node_bundling(n)->set_use_unconditional_delay();
2210             node_bundling(d)->set_used_in_unconditional_delay();
2211             _bundle_use.add_usage(avail_pipeline->resourceUse());
2212             _current_latency[d->_idx] = _bundle_cycle_number;
2213             _next_node = d;
2214             ++_bundle_instr_count;
2215 #ifndef PRODUCT
2216             _unconditional_delays++;
2217 #endif
2218             break;
2219           }
2220         }
2221       }
2222     }
2223 
2224     // No delay slot, add a nop to the usage
2225     if (!_unconditional_delay_slot) {
2226       // See if adding an instruction in the delay slot will overflow
2227       // the bundle.
2228       if (!NodeFitsInBundle(_nop)) {
2229 #ifndef PRODUCT
2230         if (_cfg->C->trace_opto_output())
2231           tty->print("#  *** STEP(1 instruction for delay slot) ***\n");
2232 #endif
2233         step(1);
2234       }
2235 
2236       _bundle_use.add_usage(_nop->pipeline()->resourceUse());
2237       _next_node = _nop;
2238       ++_bundle_instr_count;
2239     }
2240 
2241     // See if the instruction in the delay slot requires a
2242     // step of the bundles
2243     if (!NodeFitsInBundle(n)) {
2244 #ifndef PRODUCT
2245         if (_cfg->C->trace_opto_output())
2246           tty->print("#  *** STEP(branch won't fit) ***\n");
2247 #endif
2248         // Update the state information
2249         _bundle_instr_count = 0;
2250         _bundle_cycle_number += 1;
2251         _bundle_use.step(1);
2252     }
2253   }
2254 
2255   // Get the number of instructions
2256   uint instruction_count = node_pipeline->instructionCount();
2257   if (node_pipeline->mayHaveNoCode() && n->size(_regalloc) == 0)
2258     instruction_count = 0;
2259 
2260   // Compute the latency information
2261   uint delay = 0;
2262 
2263   if (instruction_count > 0 || !node_pipeline->mayHaveNoCode()) {
2264     int relative_latency = _current_latency[n->_idx] - _bundle_cycle_number;
2265     if (relative_latency < 0)
2266       relative_latency = 0;
2267 
2268     delay = _bundle_use.full_latency(relative_latency, node_usage);
2269 
2270     // Does not fit in this bundle, start a new one
2271     if (delay > 0) {
2272       step(delay);
2273 
2274 #ifndef PRODUCT
2275       if (_cfg->C->trace_opto_output())
2276         tty->print("#  *** STEP(%d) ***\n", delay);
2277 #endif
2278     }
2279   }
2280 
2281   // If this was placed in the delay slot, ignore it
2282   if (n != _unconditional_delay_slot) {
2283 
2284     if (delay == 0) {
2285       if (node_pipeline->hasMultipleBundles()) {
2286 #ifndef PRODUCT
2287         if (_cfg->C->trace_opto_output())
2288           tty->print("#  *** STEP(multiple instructions) ***\n");
2289 #endif
2290         step(1);
2291       }
2292 
2293       else if (instruction_count + _bundle_instr_count > Pipeline::_max_instrs_per_cycle) {
2294 #ifndef PRODUCT
2295         if (_cfg->C->trace_opto_output())
2296           tty->print("#  *** STEP(%d >= %d instructions) ***\n",
2297             instruction_count + _bundle_instr_count,
2298             Pipeline::_max_instrs_per_cycle);
2299 #endif
2300         step(1);
2301       }
2302     }
2303 
2304     if (node_pipeline->hasBranchDelay() && !_unconditional_delay_slot)
2305       _bundle_instr_count++;
2306 
2307     // Set the node's latency
2308     _current_latency[n->_idx] = _bundle_cycle_number;
2309 
2310     // Now merge the functional unit information
2311     if (instruction_count > 0 || !node_pipeline->mayHaveNoCode())
2312       _bundle_use.add_usage(node_usage);
2313 
2314     // Increment the number of instructions in this bundle
2315     _bundle_instr_count += instruction_count;
2316 
2317     // Remember this node for later
2318     if (n->is_Mach())
2319       _next_node = n;
2320   }
2321 
2322   // It's possible to have a BoxLock in the graph and in the _bbs mapping but
2323   // not in the bb->_nodes array.  This happens for debug-info-only BoxLocks.
2324   // 'Schedule' them (basically ignore in the schedule) but do not insert them
2325   // into the block.  All other scheduled nodes get put in the schedule here.
2326   int op = n->Opcode();
2327   if( (op == Op_Node && n->req() == 0) || // anti-dependence node OR
2328       (op != Op_Node &&         // Not an unused antidepedence node and
2329        // not an unallocated boxlock
2330        (OptoReg::is_valid(_regalloc->get_reg_first(n)) || op != Op_BoxLock)) ) {
2331 
2332     // Push any trailing projections
2333     if( bb->get_node(bb->number_of_nodes()-1) != n ) {
2334       for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2335         Node *foi = n->fast_out(i);
2336         if( foi->is_Proj() )
2337           _scheduled.push(foi);
2338       }
2339     }
2340 
2341     // Put the instruction in the schedule list
2342     _scheduled.push(n);
2343   }
2344 
2345 #ifndef PRODUCT
2346   if (_cfg->C->trace_opto_output())
2347     dump_available();
2348 #endif
2349 
2350   // Walk all the definitions, decrementing use counts, and
2351   // if a definition has a 0 use count, place it in the available list.
2352   DecrementUseCounts(n,bb);
2353 }
2354 
2355 // This method sets the use count within a basic block.  We will ignore all
2356 // uses outside the current basic block.  As we are doing a backwards walk,
2357 // any node we reach that has a use count of 0 may be scheduled.  This also
2358 // avoids the problem of cyclic references from phi nodes, as long as phi
2359 // nodes are at the front of the basic block.  This method also initializes
2360 // the available list to the set of instructions that have no uses within this
2361 // basic block.
2362 void Scheduling::ComputeUseCount(const Block *bb) {
2363 #ifndef PRODUCT
2364   if (_cfg->C->trace_opto_output())
2365     tty->print("# -> ComputeUseCount\n");
2366 #endif
2367 
2368   // Clear the list of available and scheduled instructions, just in case
2369   _available.clear();
2370   _scheduled.clear();
2371 
2372   // No delay slot specified
2373   _unconditional_delay_slot = NULL;
2374 
2375 #ifdef ASSERT
2376   for( uint i=0; i < bb->number_of_nodes(); i++ )
2377     assert( _uses[bb->get_node(i)->_idx] == 0, "_use array not clean" );
2378 #endif
2379 
2380   // Force the _uses count to never go to zero for unscheduable pieces
2381   // of the block
2382   for( uint k = 0; k < _bb_start; k++ )
2383     _uses[bb->get_node(k)->_idx] = 1;
2384   for( uint l = _bb_end; l < bb->number_of_nodes(); l++ )
2385     _uses[bb->get_node(l)->_idx] = 1;
2386 
2387   // Iterate backwards over the instructions in the block.  Don't count the
2388   // branch projections at end or the block header instructions.
2389   for( uint j = _bb_end-1; j >= _bb_start; j-- ) {
2390     Node *n = bb->get_node(j);
2391     if( n->is_Proj() ) continue; // Projections handled another way
2392 
2393     // Account for all uses
2394     for ( uint k = 0; k < n->len(); k++ ) {
2395       Node *inp = n->in(k);
2396       if (!inp) continue;
2397       assert(inp != n, "no cycles allowed" );
2398       if (_cfg->get_block_for_node(inp) == bb) { // Block-local use?
2399         if (inp->is_Proj()) { // Skip through Proj's
2400           inp = inp->in(0);
2401         }
2402         ++_uses[inp->_idx];     // Count 1 block-local use
2403       }
2404     }
2405 
2406     // If this instruction has a 0 use count, then it is available
2407     if (!_uses[n->_idx]) {
2408       _current_latency[n->_idx] = _bundle_cycle_number;
2409       AddNodeToAvailableList(n);
2410     }
2411 
2412 #ifndef PRODUCT
2413     if (_cfg->C->trace_opto_output()) {
2414       tty->print("#   uses: %3d: ", _uses[n->_idx]);
2415       n->dump();
2416     }
2417 #endif
2418   }
2419 
2420 #ifndef PRODUCT
2421   if (_cfg->C->trace_opto_output())
2422     tty->print("# <- ComputeUseCount\n");
2423 #endif
2424 }
2425 
2426 // This routine performs scheduling on each basic block in reverse order,
2427 // using instruction latencies and taking into account function unit
2428 // availability.
2429 void Scheduling::DoScheduling() {
2430 #ifndef PRODUCT
2431   if (_cfg->C->trace_opto_output())
2432     tty->print("# -> DoScheduling\n");
2433 #endif
2434 
2435   Block *succ_bb = NULL;
2436   Block *bb;
2437 
2438   // Walk over all the basic blocks in reverse order
2439   for (int i = _cfg->number_of_blocks() - 1; i >= 0; succ_bb = bb, i--) {
2440     bb = _cfg->get_block(i);
2441 
2442 #ifndef PRODUCT
2443     if (_cfg->C->trace_opto_output()) {
2444       tty->print("#  Schedule BB#%03d (initial)\n", i);
2445       for (uint j = 0; j < bb->number_of_nodes(); j++) {
2446         bb->get_node(j)->dump();
2447       }
2448     }
2449 #endif
2450 
2451     // On the head node, skip processing
2452     if (bb == _cfg->get_root_block()) {
2453       continue;
2454     }
2455 
2456     // Skip empty, connector blocks
2457     if (bb->is_connector())
2458       continue;
2459 
2460     // If the following block is not the sole successor of
2461     // this one, then reset the pipeline information
2462     if (bb->_num_succs != 1 || bb->non_connector_successor(0) != succ_bb) {
2463 #ifndef PRODUCT
2464       if (_cfg->C->trace_opto_output()) {
2465         tty->print("*** bundle start of next BB, node %d, for %d instructions\n",
2466                    _next_node->_idx, _bundle_instr_count);
2467       }
2468 #endif
2469       step_and_clear();
2470     }
2471 
2472     // Leave untouched the starting instruction, any Phis, a CreateEx node
2473     // or Top.  bb->get_node(_bb_start) is the first schedulable instruction.
2474     _bb_end = bb->number_of_nodes()-1;
2475     for( _bb_start=1; _bb_start <= _bb_end; _bb_start++ ) {
2476       Node *n = bb->get_node(_bb_start);
2477       // Things not matched, like Phinodes and ProjNodes don't get scheduled.
2478       // Also, MachIdealNodes do not get scheduled
2479       if( !n->is_Mach() ) continue;     // Skip non-machine nodes
2480       MachNode *mach = n->as_Mach();
2481       int iop = mach->ideal_Opcode();
2482       if( iop == Op_CreateEx ) continue; // CreateEx is pinned
2483       if( iop == Op_Con ) continue;      // Do not schedule Top
2484       if( iop == Op_Node &&     // Do not schedule PhiNodes, ProjNodes
2485           mach->pipeline() == MachNode::pipeline_class() &&
2486           !n->is_SpillCopy() && !n->is_MachMerge() )  // Breakpoints, Prolog, etc
2487         continue;
2488       break;                    // Funny loop structure to be sure...
2489     }
2490     // Compute last "interesting" instruction in block - last instruction we
2491     // might schedule.  _bb_end points just after last schedulable inst.  We
2492     // normally schedule conditional branches (despite them being forced last
2493     // in the block), because they have delay slots we can fill.  Calls all
2494     // have their delay slots filled in the template expansions, so we don't
2495     // bother scheduling them.
2496     Node *last = bb->get_node(_bb_end);
2497     // Ignore trailing NOPs.
2498     while (_bb_end > 0 && last->is_Mach() &&
2499            last->as_Mach()->ideal_Opcode() == Op_Con) {
2500       last = bb->get_node(--_bb_end);
2501     }
2502     assert(!last->is_Mach() || last->as_Mach()->ideal_Opcode() != Op_Con, "");
2503     if( last->is_Catch() ||
2504        // Exclude unreachable path case when Halt node is in a separate block.
2505        (_bb_end > 1 && last->is_Mach() && last->as_Mach()->ideal_Opcode() == Op_Halt) ) {
2506       // There must be a prior call.  Skip it.
2507       while( !bb->get_node(--_bb_end)->is_MachCall() ) {
2508         assert( bb->get_node(_bb_end)->is_MachProj(), "skipping projections after expected call" );
2509       }
2510     } else if( last->is_MachNullCheck() ) {
2511       // Backup so the last null-checked memory instruction is
2512       // outside the schedulable range. Skip over the nullcheck,
2513       // projection, and the memory nodes.
2514       Node *mem = last->in(1);
2515       do {
2516         _bb_end--;
2517       } while (mem != bb->get_node(_bb_end));
2518     } else {
2519       // Set _bb_end to point after last schedulable inst.
2520       _bb_end++;
2521     }
2522 
2523     assert( _bb_start <= _bb_end, "inverted block ends" );
2524 
2525     // Compute the register antidependencies for the basic block
2526     ComputeRegisterAntidependencies(bb);
2527     if (_cfg->C->failing())  return;  // too many D-U pinch points
2528 
2529     // Compute intra-bb latencies for the nodes
2530     ComputeLocalLatenciesForward(bb);
2531 
2532     // Compute the usage within the block, and set the list of all nodes
2533     // in the block that have no uses within the block.
2534     ComputeUseCount(bb);
2535 
2536     // Schedule the remaining instructions in the block
2537     while ( _available.size() > 0 ) {
2538       Node *n = ChooseNodeToBundle();
2539       guarantee(n != NULL, "no nodes available");
2540       AddNodeToBundle(n,bb);
2541     }
2542 
2543     assert( _scheduled.size() == _bb_end - _bb_start, "wrong number of instructions" );
2544 #ifdef ASSERT
2545     for( uint l = _bb_start; l < _bb_end; l++ ) {
2546       Node *n = bb->get_node(l);
2547       uint m;
2548       for( m = 0; m < _bb_end-_bb_start; m++ )
2549         if( _scheduled[m] == n )
2550           break;
2551       assert( m < _bb_end-_bb_start, "instruction missing in schedule" );
2552     }
2553 #endif
2554 
2555     // Now copy the instructions (in reverse order) back to the block
2556     for ( uint k = _bb_start; k < _bb_end; k++ )
2557       bb->map_node(_scheduled[_bb_end-k-1], k);
2558 
2559 #ifndef PRODUCT
2560     if (_cfg->C->trace_opto_output()) {
2561       tty->print("#  Schedule BB#%03d (final)\n", i);
2562       uint current = 0;
2563       for (uint j = 0; j < bb->number_of_nodes(); j++) {
2564         Node *n = bb->get_node(j);
2565         if( valid_bundle_info(n) ) {
2566           Bundle *bundle = node_bundling(n);
2567           if (bundle->instr_count() > 0 || bundle->flags() > 0) {
2568             tty->print("*** Bundle: ");
2569             bundle->dump();
2570           }
2571           n->dump();
2572         }
2573       }
2574     }
2575 #endif
2576 #ifdef ASSERT
2577   verify_good_schedule(bb,"after block local scheduling");
2578 #endif
2579   }
2580 
2581 #ifndef PRODUCT
2582   if (_cfg->C->trace_opto_output())
2583     tty->print("# <- DoScheduling\n");
2584 #endif
2585 
2586   // Record final node-bundling array location
2587   _regalloc->C->set_node_bundling_base(_node_bundling_base);
2588 
2589 } // end DoScheduling
2590 
2591 // Verify that no live-range used in the block is killed in the block by a
2592 // wrong DEF.  This doesn't verify live-ranges that span blocks.
2593 
2594 // Check for edge existence.  Used to avoid adding redundant precedence edges.
2595 static bool edge_from_to( Node *from, Node *to ) {
2596   for( uint i=0; i<from->len(); i++ )
2597     if( from->in(i) == to )
2598       return true;
2599   return false;
2600 }
2601 
2602 #ifdef ASSERT
2603 void Scheduling::verify_do_def( Node *n, OptoReg::Name def, const char *msg ) {
2604   // Check for bad kills
2605   if( OptoReg::is_valid(def) ) { // Ignore stores & control flow
2606     Node *prior_use = _reg_node[def];
2607     if( prior_use && !edge_from_to(prior_use,n) ) {
2608       tty->print("%s = ",OptoReg::as_VMReg(def)->name());
2609       n->dump();
2610       tty->print_cr("...");
2611       prior_use->dump();
2612       assert(edge_from_to(prior_use,n),msg);
2613     }
2614     _reg_node.map(def,NULL); // Kill live USEs
2615   }
2616 }
2617 
2618 void Scheduling::verify_good_schedule( Block *b, const char *msg ) {
2619 
2620   // Zap to something reasonable for the verify code
2621   _reg_node.clear();
2622 
2623   // Walk over the block backwards.  Check to make sure each DEF doesn't
2624   // kill a live value (other than the one it's supposed to).  Add each
2625   // USE to the live set.
2626   for( uint i = b->number_of_nodes()-1; i >= _bb_start; i-- ) {
2627     Node *n = b->get_node(i);
2628     int n_op = n->Opcode();
2629     if( n_op == Op_MachProj && n->ideal_reg() == MachProjNode::fat_proj ) {
2630       // Fat-proj kills a slew of registers
2631       RegMask rm = n->out_RegMask();// Make local copy
2632       while( rm.is_NotEmpty() ) {
2633         OptoReg::Name kill = rm.find_first_elem();
2634         rm.Remove(kill);
2635         verify_do_def( n, kill, msg );
2636       }
2637     } else if( n_op != Op_Node ) { // Avoid brand new antidependence nodes
2638       // Get DEF'd registers the normal way
2639       verify_do_def( n, _regalloc->get_reg_first(n), msg );
2640       verify_do_def( n, _regalloc->get_reg_second(n), msg );
2641     }
2642 
2643     // Now make all USEs live
2644     for( uint i=1; i<n->req(); i++ ) {
2645       Node *def = n->in(i);
2646       assert(def != 0, "input edge required");
2647       OptoReg::Name reg_lo = _regalloc->get_reg_first(def);
2648       OptoReg::Name reg_hi = _regalloc->get_reg_second(def);
2649       if( OptoReg::is_valid(reg_lo) ) {
2650         assert(!_reg_node[reg_lo] || edge_from_to(_reg_node[reg_lo],def), msg);
2651         _reg_node.map(reg_lo,n);
2652       }
2653       if( OptoReg::is_valid(reg_hi) ) {
2654         assert(!_reg_node[reg_hi] || edge_from_to(_reg_node[reg_hi],def), msg);
2655         _reg_node.map(reg_hi,n);
2656       }
2657     }
2658 
2659   }
2660 
2661   // Zap to something reasonable for the Antidependence code
2662   _reg_node.clear();
2663 }
2664 #endif
2665 
2666 // Conditionally add precedence edges.  Avoid putting edges on Projs.
2667 static void add_prec_edge_from_to( Node *from, Node *to ) {
2668   if( from->is_Proj() ) {       // Put precedence edge on Proj's input
2669     assert( from->req() == 1 && (from->len() == 1 || from->in(1)==0), "no precedence edges on projections" );
2670     from = from->in(0);
2671   }
2672   if( from != to &&             // No cycles (for things like LD L0,[L0+4] )
2673       !edge_from_to( from, to ) ) // Avoid duplicate edge
2674     from->add_prec(to);
2675 }
2676 
2677 void Scheduling::anti_do_def( Block *b, Node *def, OptoReg::Name def_reg, int is_def ) {
2678   if( !OptoReg::is_valid(def_reg) ) // Ignore stores & control flow
2679     return;
2680 
2681   Node *pinch = _reg_node[def_reg]; // Get pinch point
2682   if ((pinch == NULL) || _cfg->get_block_for_node(pinch) != b || // No pinch-point yet?
2683       is_def ) {    // Check for a true def (not a kill)
2684     _reg_node.map(def_reg,def); // Record def/kill as the optimistic pinch-point
2685     return;
2686   }
2687 
2688   Node *kill = def;             // Rename 'def' to more descriptive 'kill'
2689   debug_only( def = (Node*)0xdeadbeef; )
2690 
2691   // After some number of kills there _may_ be a later def
2692   Node *later_def = NULL;
2693 
2694   // Finding a kill requires a real pinch-point.
2695   // Check for not already having a pinch-point.
2696   // Pinch points are Op_Node's.
2697   if( pinch->Opcode() != Op_Node ) { // Or later-def/kill as pinch-point?
2698     later_def = pinch;            // Must be def/kill as optimistic pinch-point
2699     if ( _pinch_free_list.size() > 0) {
2700       pinch = _pinch_free_list.pop();
2701     } else {
2702       pinch = new (_cfg->C) Node(1); // Pinch point to-be
2703     }
2704     if (pinch->_idx >= _regalloc->node_regs_max_index()) {
2705       _cfg->C->record_method_not_compilable("too many D-U pinch points");
2706       return;
2707     }
2708     _cfg->map_node_to_block(pinch, b);      // Pretend it's valid in this block (lazy init)
2709     _reg_node.map(def_reg,pinch); // Record pinch-point
2710     //_regalloc->set_bad(pinch->_idx); // Already initialized this way.
2711     if( later_def->outcnt() == 0 || later_def->ideal_reg() == MachProjNode::fat_proj ) { // Distinguish def from kill
2712       pinch->init_req(0, _cfg->C->top());     // set not NULL for the next call
2713       add_prec_edge_from_to(later_def,pinch); // Add edge from kill to pinch
2714       later_def = NULL;           // and no later def
2715     }
2716     pinch->set_req(0,later_def);  // Hook later def so we can find it
2717   } else {                        // Else have valid pinch point
2718     if( pinch->in(0) )            // If there is a later-def
2719       later_def = pinch->in(0);   // Get it
2720   }
2721 
2722   // Add output-dependence edge from later def to kill
2723   if( later_def )               // If there is some original def
2724     add_prec_edge_from_to(later_def,kill); // Add edge from def to kill
2725 
2726   // See if current kill is also a use, and so is forced to be the pinch-point.
2727   if( pinch->Opcode() == Op_Node ) {
2728     Node *uses = kill->is_Proj() ? kill->in(0) : kill;
2729     for( uint i=1; i<uses->req(); i++ ) {
2730       if( _regalloc->get_reg_first(uses->in(i)) == def_reg ||
2731           _regalloc->get_reg_second(uses->in(i)) == def_reg ) {
2732         // Yes, found a use/kill pinch-point
2733         pinch->set_req(0,NULL);  //
2734         pinch->replace_by(kill); // Move anti-dep edges up
2735         pinch = kill;
2736         _reg_node.map(def_reg,pinch);
2737         return;
2738       }
2739     }
2740   }
2741 
2742   // Add edge from kill to pinch-point
2743   add_prec_edge_from_to(kill,pinch);
2744 }
2745 
2746 void Scheduling::anti_do_use( Block *b, Node *use, OptoReg::Name use_reg ) {
2747   if( !OptoReg::is_valid(use_reg) ) // Ignore stores & control flow
2748     return;
2749   Node *pinch = _reg_node[use_reg]; // Get pinch point
2750   // Check for no later def_reg/kill in block
2751   if ((pinch != NULL) && _cfg->get_block_for_node(pinch) == b &&
2752       // Use has to be block-local as well
2753       _cfg->get_block_for_node(use) == b) {
2754     if( pinch->Opcode() == Op_Node && // Real pinch-point (not optimistic?)
2755         pinch->req() == 1 ) {   // pinch not yet in block?
2756       pinch->del_req(0);        // yank pointer to later-def, also set flag
2757       // Insert the pinch-point in the block just after the last use
2758       b->insert_node(pinch, b->find_node(use) + 1);
2759       _bb_end++;                // Increase size scheduled region in block
2760     }
2761 
2762     add_prec_edge_from_to(pinch,use);
2763   }
2764 }
2765 
2766 // We insert antidependences between the reads and following write of
2767 // allocated registers to prevent illegal code motion. Hopefully, the
2768 // number of added references should be fairly small, especially as we
2769 // are only adding references within the current basic block.
2770 void Scheduling::ComputeRegisterAntidependencies(Block *b) {
2771 
2772 #ifdef ASSERT
2773   verify_good_schedule(b,"before block local scheduling");
2774 #endif
2775 
2776   // A valid schedule, for each register independently, is an endless cycle
2777   // of: a def, then some uses (connected to the def by true dependencies),
2778   // then some kills (defs with no uses), finally the cycle repeats with a new
2779   // def.  The uses are allowed to float relative to each other, as are the
2780   // kills.  No use is allowed to slide past a kill (or def).  This requires
2781   // antidependencies between all uses of a single def and all kills that
2782   // follow, up to the next def.  More edges are redundant, because later defs
2783   // & kills are already serialized with true or antidependencies.  To keep
2784   // the edge count down, we add a 'pinch point' node if there's more than
2785   // one use or more than one kill/def.
2786 
2787   // We add dependencies in one bottom-up pass.
2788 
2789   // For each instruction we handle it's DEFs/KILLs, then it's USEs.
2790 
2791   // For each DEF/KILL, we check to see if there's a prior DEF/KILL for this
2792   // register.  If not, we record the DEF/KILL in _reg_node, the
2793   // register-to-def mapping.  If there is a prior DEF/KILL, we insert a
2794   // "pinch point", a new Node that's in the graph but not in the block.
2795   // We put edges from the prior and current DEF/KILLs to the pinch point.
2796   // We put the pinch point in _reg_node.  If there's already a pinch point
2797   // we merely add an edge from the current DEF/KILL to the pinch point.
2798 
2799   // After doing the DEF/KILLs, we handle USEs.  For each used register, we
2800   // put an edge from the pinch point to the USE.
2801 
2802   // To be expedient, the _reg_node array is pre-allocated for the whole
2803   // compilation.  _reg_node is lazily initialized; it either contains a NULL,
2804   // or a valid def/kill/pinch-point, or a leftover node from some prior
2805   // block.  Leftover node from some prior block is treated like a NULL (no
2806   // prior def, so no anti-dependence needed).  Valid def is distinguished by
2807   // it being in the current block.
2808   bool fat_proj_seen = false;
2809   uint last_safept = _bb_end-1;
2810   Node* end_node         = (_bb_end-1 >= _bb_start) ? b->get_node(last_safept) : NULL;
2811   Node* last_safept_node = end_node;
2812   for( uint i = _bb_end-1; i >= _bb_start; i-- ) {
2813     Node *n = b->get_node(i);
2814     int is_def = n->outcnt();   // def if some uses prior to adding precedence edges
2815     if( n->is_MachProj() && n->ideal_reg() == MachProjNode::fat_proj ) {
2816       // Fat-proj kills a slew of registers
2817       // This can add edges to 'n' and obscure whether or not it was a def,
2818       // hence the is_def flag.
2819       fat_proj_seen = true;
2820       RegMask rm = n->out_RegMask();// Make local copy
2821       while( rm.is_NotEmpty() ) {
2822         OptoReg::Name kill = rm.find_first_elem();
2823         rm.Remove(kill);
2824         anti_do_def( b, n, kill, is_def );
2825       }
2826     } else {
2827       // Get DEF'd registers the normal way
2828       anti_do_def( b, n, _regalloc->get_reg_first(n), is_def );
2829       anti_do_def( b, n, _regalloc->get_reg_second(n), is_def );
2830     }
2831 
2832     // Kill projections on a branch should appear to occur on the
2833     // branch, not afterwards, so grab the masks from the projections
2834     // and process them.
2835     if (n->is_MachBranch() || n->is_Mach() && n->as_Mach()->ideal_Opcode() == Op_Jump) {
2836       for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2837         Node* use = n->fast_out(i);
2838         if (use->is_Proj()) {
2839           RegMask rm = use->out_RegMask();// Make local copy
2840           while( rm.is_NotEmpty() ) {
2841             OptoReg::Name kill = rm.find_first_elem();
2842             rm.Remove(kill);
2843             anti_do_def( b, n, kill, false );
2844           }
2845         }
2846       }
2847     }
2848 
2849     // Check each register used by this instruction for a following DEF/KILL
2850     // that must occur afterward and requires an anti-dependence edge.
2851     for( uint j=0; j<n->req(); j++ ) {
2852       Node *def = n->in(j);
2853       if( def ) {
2854         assert( !def->is_MachProj() || def->ideal_reg() != MachProjNode::fat_proj, "" );
2855         anti_do_use( b, n, _regalloc->get_reg_first(def) );
2856         anti_do_use( b, n, _regalloc->get_reg_second(def) );
2857       }
2858     }
2859     // Do not allow defs of new derived values to float above GC
2860     // points unless the base is definitely available at the GC point.
2861 
2862     Node *m = b->get_node(i);
2863 
2864     // Add precedence edge from following safepoint to use of derived pointer
2865     if( last_safept_node != end_node &&
2866         m != last_safept_node) {
2867       for (uint k = 1; k < m->req(); k++) {
2868         const Type *t = m->in(k)->bottom_type();
2869         if( t->isa_oop_ptr() &&
2870             t->is_ptr()->offset() != 0 ) {
2871           last_safept_node->add_prec( m );
2872           break;
2873         }
2874       }
2875     }
2876 
2877     if( n->jvms() ) {           // Precedence edge from derived to safept
2878       // Check if last_safept_node was moved by pinch-point insertion in anti_do_use()
2879       if( b->get_node(last_safept) != last_safept_node ) {
2880         last_safept = b->find_node(last_safept_node);
2881       }
2882       for( uint j=last_safept; j > i; j-- ) {
2883         Node *mach = b->get_node(j);
2884         if( mach->is_Mach() && mach->as_Mach()->ideal_Opcode() == Op_AddP )
2885           mach->add_prec( n );
2886       }
2887       last_safept = i;
2888       last_safept_node = m;
2889     }
2890   }
2891 
2892   if (fat_proj_seen) {
2893     // Garbage collect pinch nodes that were not consumed.
2894     // They are usually created by a fat kill MachProj for a call.
2895     garbage_collect_pinch_nodes();
2896   }
2897 }
2898 
2899 // Garbage collect pinch nodes for reuse by other blocks.
2900 //
2901 // The block scheduler's insertion of anti-dependence
2902 // edges creates many pinch nodes when the block contains
2903 // 2 or more Calls.  A pinch node is used to prevent a
2904 // combinatorial explosion of edges.  If a set of kills for a
2905 // register is anti-dependent on a set of uses (or defs), rather
2906 // than adding an edge in the graph between each pair of kill
2907 // and use (or def), a pinch is inserted between them:
2908 //
2909 //            use1   use2  use3
2910 //                \   |   /
2911 //                 \  |  /
2912 //                  pinch
2913 //                 /  |  \
2914 //                /   |   \
2915 //            kill1 kill2 kill3
2916 //
2917 // One pinch node is created per register killed when
2918 // the second call is encountered during a backwards pass
2919 // over the block.  Most of these pinch nodes are never
2920 // wired into the graph because the register is never
2921 // used or def'ed in the block.
2922 //
2923 void Scheduling::garbage_collect_pinch_nodes() {
2924 #ifndef PRODUCT
2925     if (_cfg->C->trace_opto_output()) tty->print("Reclaimed pinch nodes:");
2926 #endif
2927     int trace_cnt = 0;
2928     for (uint k = 0; k < _reg_node.Size(); k++) {
2929       Node* pinch = _reg_node[k];
2930       if ((pinch != NULL) && pinch->Opcode() == Op_Node &&
2931           // no predecence input edges
2932           (pinch->req() == pinch->len() || pinch->in(pinch->req()) == NULL) ) {
2933         cleanup_pinch(pinch);
2934         _pinch_free_list.push(pinch);
2935         _reg_node.map(k, NULL);
2936 #ifndef PRODUCT
2937         if (_cfg->C->trace_opto_output()) {
2938           trace_cnt++;
2939           if (trace_cnt > 40) {
2940             tty->print("\n");
2941             trace_cnt = 0;
2942           }
2943           tty->print(" %d", pinch->_idx);
2944         }
2945 #endif
2946       }
2947     }
2948 #ifndef PRODUCT
2949     if (_cfg->C->trace_opto_output()) tty->print("\n");
2950 #endif
2951 }
2952 
2953 // Clean up a pinch node for reuse.
2954 void Scheduling::cleanup_pinch( Node *pinch ) {
2955   assert (pinch && pinch->Opcode() == Op_Node && pinch->req() == 1, "just checking");
2956 
2957   for (DUIterator_Last imin, i = pinch->last_outs(imin); i >= imin; ) {
2958     Node* use = pinch->last_out(i);
2959     uint uses_found = 0;
2960     for (uint j = use->req(); j < use->len(); j++) {
2961       if (use->in(j) == pinch) {
2962         use->rm_prec(j);
2963         uses_found++;
2964       }
2965     }
2966     assert(uses_found > 0, "must be a precedence edge");
2967     i -= uses_found;    // we deleted 1 or more copies of this edge
2968   }
2969   // May have a later_def entry
2970   pinch->set_req(0, NULL);
2971 }
2972 
2973 #ifndef PRODUCT
2974 
2975 void Scheduling::dump_available() const {
2976   tty->print("#Availist  ");
2977   for (uint i = 0; i < _available.size(); i++)
2978     tty->print(" N%d/l%d", _available[i]->_idx,_current_latency[_available[i]->_idx]);
2979   tty->cr();
2980 }
2981 
2982 // Print Scheduling Statistics
2983 void Scheduling::print_statistics() {
2984   // Print the size added by nops for bundling
2985   tty->print("Nops added %d bytes to total of %d bytes",
2986     _total_nop_size, _total_method_size);
2987   if (_total_method_size > 0)
2988     tty->print(", for %.2f%%",
2989       ((double)_total_nop_size) / ((double) _total_method_size) * 100.0);
2990   tty->print("\n");
2991 
2992   // Print the number of branch shadows filled
2993   if (Pipeline::_branch_has_delay_slot) {
2994     tty->print("Of %d branches, %d had unconditional delay slots filled",
2995       _total_branches, _total_unconditional_delays);
2996     if (_total_branches > 0)
2997       tty->print(", for %.2f%%",
2998         ((double)_total_unconditional_delays) / ((double)_total_branches) * 100.0);
2999     tty->print("\n");
3000   }
3001 
3002   uint total_instructions = 0, total_bundles = 0;
3003 
3004   for (uint i = 1; i <= Pipeline::_max_instrs_per_cycle; i++) {
3005     uint bundle_count   = _total_instructions_per_bundle[i];
3006     total_instructions += bundle_count * i;
3007     total_bundles      += bundle_count;
3008   }
3009 
3010   if (total_bundles > 0)
3011     tty->print("Average ILP (excluding nops) is %.2f\n",
3012       ((double)total_instructions) / ((double)total_bundles));
3013 }
3014 #endif