1 /*
   2  * Copyright (c) 1997, 2015, 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/macroAssembler.hpp"
  27 #include "asm/macroAssembler.inline.hpp"
  28 #include "ci/ciReplay.hpp"
  29 #include "classfile/systemDictionary.hpp"
  30 #include "code/exceptionHandlerTable.hpp"
  31 #include "code/nmethod.hpp"
  32 #include "compiler/compileBroker.hpp"
  33 #include "compiler/compileLog.hpp"
  34 #include "compiler/disassembler.hpp"
  35 #include "compiler/oopMap.hpp"
  36 #include "opto/addnode.hpp"
  37 #include "opto/block.hpp"
  38 #include "opto/c2compiler.hpp"
  39 #include "opto/callGenerator.hpp"
  40 #include "opto/callnode.hpp"
  41 #include "opto/cfgnode.hpp"
  42 #include "opto/chaitin.hpp"
  43 #include "opto/compile.hpp"
  44 #include "opto/connode.hpp"
  45 #include "opto/convertnode.hpp"
  46 #include "opto/divnode.hpp"
  47 #include "opto/escape.hpp"
  48 #include "opto/idealGraphPrinter.hpp"
  49 #include "opto/loopnode.hpp"
  50 #include "opto/machnode.hpp"
  51 #include "opto/macro.hpp"
  52 #include "opto/matcher.hpp"
  53 #include "opto/mathexactnode.hpp"
  54 #include "opto/memnode.hpp"
  55 #include "opto/mulnode.hpp"
  56 #include "opto/narrowptrnode.hpp"
  57 #include "opto/node.hpp"
  58 #include "opto/opcodes.hpp"
  59 #include "opto/output.hpp"
  60 #include "opto/parse.hpp"
  61 #include "opto/phaseX.hpp"
  62 #include "opto/rootnode.hpp"
  63 #include "opto/runtime.hpp"
  64 #include "opto/stringopts.hpp"
  65 #include "opto/type.hpp"
  66 #include "opto/vectornode.hpp"
  67 #include "runtime/arguments.hpp"
  68 #include "runtime/sharedRuntime.hpp"
  69 #include "runtime/signature.hpp"
  70 #include "runtime/stubRoutines.hpp"
  71 #include "runtime/timer.hpp"
  72 #include "utilities/copy.hpp"
  73 
  74 
  75 // -------------------- Compile::mach_constant_base_node -----------------------
  76 // Constant table base node singleton.
  77 MachConstantBaseNode* Compile::mach_constant_base_node() {
  78   if (_mach_constant_base_node == NULL) {
  79     _mach_constant_base_node = new MachConstantBaseNode();
  80     _mach_constant_base_node->add_req(C->root());
  81   }
  82   return _mach_constant_base_node;
  83 }
  84 
  85 
  86 /// Support for intrinsics.
  87 
  88 // Return the index at which m must be inserted (or already exists).
  89 // The sort order is by the address of the ciMethod, with is_virtual as minor key.
  90 int Compile::intrinsic_insertion_index(ciMethod* m, bool is_virtual) {
  91 #ifdef ASSERT
  92   for (int i = 1; i < _intrinsics->length(); i++) {
  93     CallGenerator* cg1 = _intrinsics->at(i-1);
  94     CallGenerator* cg2 = _intrinsics->at(i);
  95     assert(cg1->method() != cg2->method()
  96            ? cg1->method()     < cg2->method()
  97            : cg1->is_virtual() < cg2->is_virtual(),
  98            "compiler intrinsics list must stay sorted");
  99   }
 100 #endif
 101   // Binary search sorted list, in decreasing intervals [lo, hi].
 102   int lo = 0, hi = _intrinsics->length()-1;
 103   while (lo <= hi) {
 104     int mid = (uint)(hi + lo) / 2;
 105     ciMethod* mid_m = _intrinsics->at(mid)->method();
 106     if (m < mid_m) {
 107       hi = mid-1;
 108     } else if (m > mid_m) {
 109       lo = mid+1;
 110     } else {
 111       // look at minor sort key
 112       bool mid_virt = _intrinsics->at(mid)->is_virtual();
 113       if (is_virtual < mid_virt) {
 114         hi = mid-1;
 115       } else if (is_virtual > mid_virt) {
 116         lo = mid+1;
 117       } else {
 118         return mid;  // exact match
 119       }
 120     }
 121   }
 122   return lo;  // inexact match
 123 }
 124 
 125 void Compile::register_intrinsic(CallGenerator* cg) {
 126   if (_intrinsics == NULL) {
 127     _intrinsics = new (comp_arena())GrowableArray<CallGenerator*>(comp_arena(), 60, 0, NULL);
 128   }
 129   // This code is stolen from ciObjectFactory::insert.
 130   // Really, GrowableArray should have methods for
 131   // insert_at, remove_at, and binary_search.
 132   int len = _intrinsics->length();
 133   int index = intrinsic_insertion_index(cg->method(), cg->is_virtual());
 134   if (index == len) {
 135     _intrinsics->append(cg);
 136   } else {
 137 #ifdef ASSERT
 138     CallGenerator* oldcg = _intrinsics->at(index);
 139     assert(oldcg->method() != cg->method() || oldcg->is_virtual() != cg->is_virtual(), "don't register twice");
 140 #endif
 141     _intrinsics->append(_intrinsics->at(len-1));
 142     int pos;
 143     for (pos = len-2; pos >= index; pos--) {
 144       _intrinsics->at_put(pos+1,_intrinsics->at(pos));
 145     }
 146     _intrinsics->at_put(index, cg);
 147   }
 148   assert(find_intrinsic(cg->method(), cg->is_virtual()) == cg, "registration worked");
 149 }
 150 
 151 CallGenerator* Compile::find_intrinsic(ciMethod* m, bool is_virtual) {
 152   assert(m->is_loaded(), "don't try this on unloaded methods");
 153   if (_intrinsics != NULL) {
 154     int index = intrinsic_insertion_index(m, is_virtual);
 155     if (index < _intrinsics->length()
 156         && _intrinsics->at(index)->method() == m
 157         && _intrinsics->at(index)->is_virtual() == is_virtual) {
 158       return _intrinsics->at(index);
 159     }
 160   }
 161   // Lazily create intrinsics for intrinsic IDs well-known in the runtime.
 162   if (m->intrinsic_id() != vmIntrinsics::_none &&
 163       m->intrinsic_id() <= vmIntrinsics::LAST_COMPILER_INLINE) {
 164     CallGenerator* cg = make_vm_intrinsic(m, is_virtual);
 165     if (cg != NULL) {
 166       // Save it for next time:
 167       register_intrinsic(cg);
 168       return cg;
 169     } else {
 170       gather_intrinsic_statistics(m->intrinsic_id(), is_virtual, _intrinsic_disabled);
 171     }
 172   }
 173   return NULL;
 174 }
 175 
 176 // Compile:: register_library_intrinsics and make_vm_intrinsic are defined
 177 // in library_call.cpp.
 178 
 179 
 180 #ifndef PRODUCT
 181 // statistics gathering...
 182 
 183 juint  Compile::_intrinsic_hist_count[vmIntrinsics::ID_LIMIT] = {0};
 184 jubyte Compile::_intrinsic_hist_flags[vmIntrinsics::ID_LIMIT] = {0};
 185 
 186 bool Compile::gather_intrinsic_statistics(vmIntrinsics::ID id, bool is_virtual, int flags) {
 187   assert(id > vmIntrinsics::_none && id < vmIntrinsics::ID_LIMIT, "oob");
 188   int oflags = _intrinsic_hist_flags[id];
 189   assert(flags != 0, "what happened?");
 190   if (is_virtual) {
 191     flags |= _intrinsic_virtual;
 192   }
 193   bool changed = (flags != oflags);
 194   if ((flags & _intrinsic_worked) != 0) {
 195     juint count = (_intrinsic_hist_count[id] += 1);
 196     if (count == 1) {
 197       changed = true;           // first time
 198     }
 199     // increment the overall count also:
 200     _intrinsic_hist_count[vmIntrinsics::_none] += 1;
 201   }
 202   if (changed) {
 203     if (((oflags ^ flags) & _intrinsic_virtual) != 0) {
 204       // Something changed about the intrinsic's virtuality.
 205       if ((flags & _intrinsic_virtual) != 0) {
 206         // This is the first use of this intrinsic as a virtual call.
 207         if (oflags != 0) {
 208           // We already saw it as a non-virtual, so note both cases.
 209           flags |= _intrinsic_both;
 210         }
 211       } else if ((oflags & _intrinsic_both) == 0) {
 212         // This is the first use of this intrinsic as a non-virtual
 213         flags |= _intrinsic_both;
 214       }
 215     }
 216     _intrinsic_hist_flags[id] = (jubyte) (oflags | flags);
 217   }
 218   // update the overall flags also:
 219   _intrinsic_hist_flags[vmIntrinsics::_none] |= (jubyte) flags;
 220   return changed;
 221 }
 222 
 223 static char* format_flags(int flags, char* buf) {
 224   buf[0] = 0;
 225   if ((flags & Compile::_intrinsic_worked) != 0)    strcat(buf, ",worked");
 226   if ((flags & Compile::_intrinsic_failed) != 0)    strcat(buf, ",failed");
 227   if ((flags & Compile::_intrinsic_disabled) != 0)  strcat(buf, ",disabled");
 228   if ((flags & Compile::_intrinsic_virtual) != 0)   strcat(buf, ",virtual");
 229   if ((flags & Compile::_intrinsic_both) != 0)      strcat(buf, ",nonvirtual");
 230   if (buf[0] == 0)  strcat(buf, ",");
 231   assert(buf[0] == ',', "must be");
 232   return &buf[1];
 233 }
 234 
 235 void Compile::print_intrinsic_statistics() {
 236   char flagsbuf[100];
 237   ttyLocker ttyl;
 238   if (xtty != NULL)  xtty->head("statistics type='intrinsic'");
 239   tty->print_cr("Compiler intrinsic usage:");
 240   juint total = _intrinsic_hist_count[vmIntrinsics::_none];
 241   if (total == 0)  total = 1;  // avoid div0 in case of no successes
 242   #define PRINT_STAT_LINE(name, c, f) \
 243     tty->print_cr("  %4d (%4.1f%%) %s (%s)", (int)(c), ((c) * 100.0) / total, name, f);
 244   for (int index = 1 + (int)vmIntrinsics::_none; index < (int)vmIntrinsics::ID_LIMIT; index++) {
 245     vmIntrinsics::ID id = (vmIntrinsics::ID) index;
 246     int   flags = _intrinsic_hist_flags[id];
 247     juint count = _intrinsic_hist_count[id];
 248     if ((flags | count) != 0) {
 249       PRINT_STAT_LINE(vmIntrinsics::name_at(id), count, format_flags(flags, flagsbuf));
 250     }
 251   }
 252   PRINT_STAT_LINE("total", total, format_flags(_intrinsic_hist_flags[vmIntrinsics::_none], flagsbuf));
 253   if (xtty != NULL)  xtty->tail("statistics");
 254 }
 255 
 256 void Compile::print_statistics() {
 257   { ttyLocker ttyl;
 258     if (xtty != NULL)  xtty->head("statistics type='opto'");
 259     Parse::print_statistics();
 260     PhaseCCP::print_statistics();
 261     PhaseRegAlloc::print_statistics();
 262     Scheduling::print_statistics();
 263     PhasePeephole::print_statistics();
 264     PhaseIdealLoop::print_statistics();
 265     if (xtty != NULL)  xtty->tail("statistics");
 266   }
 267   if (_intrinsic_hist_flags[vmIntrinsics::_none] != 0) {
 268     // put this under its own <statistics> element.
 269     print_intrinsic_statistics();
 270   }
 271 }
 272 #endif //PRODUCT
 273 
 274 // Support for bundling info
 275 Bundle* Compile::node_bundling(const Node *n) {
 276   assert(valid_bundle_info(n), "oob");
 277   return &_node_bundling_base[n->_idx];
 278 }
 279 
 280 bool Compile::valid_bundle_info(const Node *n) {
 281   return (_node_bundling_limit > n->_idx);
 282 }
 283 
 284 
 285 void Compile::gvn_replace_by(Node* n, Node* nn) {
 286   for (DUIterator_Last imin, i = n->last_outs(imin); i >= imin; ) {
 287     Node* use = n->last_out(i);
 288     bool is_in_table = initial_gvn()->hash_delete(use);
 289     uint uses_found = 0;
 290     for (uint j = 0; j < use->len(); j++) {
 291       if (use->in(j) == n) {
 292         if (j < use->req())
 293           use->set_req(j, nn);
 294         else
 295           use->set_prec(j, nn);
 296         uses_found++;
 297       }
 298     }
 299     if (is_in_table) {
 300       // reinsert into table
 301       initial_gvn()->hash_find_insert(use);
 302     }
 303     record_for_igvn(use);
 304     i -= uses_found;    // we deleted 1 or more copies of this edge
 305   }
 306 }
 307 
 308 
 309 static inline bool not_a_node(const Node* n) {
 310   if (n == NULL)                   return true;
 311   if (((intptr_t)n & 1) != 0)      return true;  // uninitialized, etc.
 312   if (*(address*)n == badAddress)  return true;  // kill by Node::destruct
 313   return false;
 314 }
 315 
 316 // Identify all nodes that are reachable from below, useful.
 317 // Use breadth-first pass that records state in a Unique_Node_List,
 318 // recursive traversal is slower.
 319 void Compile::identify_useful_nodes(Unique_Node_List &useful) {
 320   int estimated_worklist_size = unique();
 321   useful.map( estimated_worklist_size, NULL );  // preallocate space
 322 
 323   // Initialize worklist
 324   if (root() != NULL)     { useful.push(root()); }
 325   // If 'top' is cached, declare it useful to preserve cached node
 326   if( cached_top_node() ) { useful.push(cached_top_node()); }
 327 
 328   // Push all useful nodes onto the list, breadthfirst
 329   for( uint next = 0; next < useful.size(); ++next ) {
 330     assert( next < unique(), "Unique useful nodes < total nodes");
 331     Node *n  = useful.at(next);
 332     uint max = n->len();
 333     for( uint i = 0; i < max; ++i ) {
 334       Node *m = n->in(i);
 335       if (not_a_node(m))  continue;
 336       useful.push(m);
 337     }
 338   }
 339 }
 340 
 341 // Update dead_node_list with any missing dead nodes using useful
 342 // list. Consider all non-useful nodes to be useless i.e., dead nodes.
 343 void Compile::update_dead_node_list(Unique_Node_List &useful) {
 344   uint max_idx = unique();
 345   VectorSet& useful_node_set = useful.member_set();
 346 
 347   for (uint node_idx = 0; node_idx < max_idx; node_idx++) {
 348     // If node with index node_idx is not in useful set,
 349     // mark it as dead in dead node list.
 350     if (! useful_node_set.test(node_idx) ) {
 351       record_dead_node(node_idx);
 352     }
 353   }
 354 }
 355 
 356 void Compile::remove_useless_late_inlines(GrowableArray<CallGenerator*>* inlines, Unique_Node_List &useful) {
 357   int shift = 0;
 358   for (int i = 0; i < inlines->length(); i++) {
 359     CallGenerator* cg = inlines->at(i);
 360     CallNode* call = cg->call_node();
 361     if (shift > 0) {
 362       inlines->at_put(i-shift, cg);
 363     }
 364     if (!useful.member(call)) {
 365       shift++;
 366     }
 367   }
 368   inlines->trunc_to(inlines->length()-shift);
 369 }
 370 
 371 // Disconnect all useless nodes by disconnecting those at the boundary.
 372 void Compile::remove_useless_nodes(Unique_Node_List &useful) {
 373   uint next = 0;
 374   while (next < useful.size()) {
 375     Node *n = useful.at(next++);
 376     if (n->is_SafePoint()) {
 377       // We're done with a parsing phase. Replaced nodes are not valid
 378       // beyond that point.
 379       n->as_SafePoint()->delete_replaced_nodes();
 380     }
 381     // Use raw traversal of out edges since this code removes out edges
 382     int max = n->outcnt();
 383     for (int j = 0; j < max; ++j) {
 384       Node* child = n->raw_out(j);
 385       if (! useful.member(child)) {
 386         assert(!child->is_top() || child != top(),
 387                "If top is cached in Compile object it is in useful list");
 388         // Only need to remove this out-edge to the useless node
 389         n->raw_del_out(j);
 390         --j;
 391         --max;
 392       }
 393     }
 394     if (n->outcnt() == 1 && n->has_special_unique_user()) {
 395       record_for_igvn(n->unique_out());
 396     }
 397   }
 398   // Remove useless macro and predicate opaq nodes
 399   for (int i = C->macro_count()-1; i >= 0; i--) {
 400     Node* n = C->macro_node(i);
 401     if (!useful.member(n)) {
 402       remove_macro_node(n);
 403     }
 404   }
 405   // Remove useless expensive node
 406   for (int i = C->expensive_count()-1; i >= 0; i--) {
 407     Node* n = C->expensive_node(i);
 408     if (!useful.member(n)) {
 409       remove_expensive_node(n);
 410     }
 411   }
 412   // clean up the late inline lists
 413   remove_useless_late_inlines(&_string_late_inlines, useful);
 414   remove_useless_late_inlines(&_boxing_late_inlines, useful);
 415   remove_useless_late_inlines(&_late_inlines, useful);
 416   debug_only(verify_graph_edges(true/*check for no_dead_code*/);)
 417 }
 418 
 419 //------------------------------frame_size_in_words-----------------------------
 420 // frame_slots in units of words
 421 int Compile::frame_size_in_words() const {
 422   // shift is 0 in LP32 and 1 in LP64
 423   const int shift = (LogBytesPerWord - LogBytesPerInt);
 424   int words = _frame_slots >> shift;
 425   assert( words << shift == _frame_slots, "frame size must be properly aligned in LP64" );
 426   return words;
 427 }
 428 
 429 // To bang the stack of this compiled method we use the stack size
 430 // that the interpreter would need in case of a deoptimization. This
 431 // removes the need to bang the stack in the deoptimization blob which
 432 // in turn simplifies stack overflow handling.
 433 int Compile::bang_size_in_bytes() const {
 434   return MAX2(frame_size_in_bytes() + os::extra_bang_size_in_bytes(), _interpreter_frame_size);
 435 }
 436 
 437 // ============================================================================
 438 //------------------------------CompileWrapper---------------------------------
 439 class CompileWrapper : public StackObj {
 440   Compile *const _compile;
 441  public:
 442   CompileWrapper(Compile* compile);
 443 
 444   ~CompileWrapper();
 445 };
 446 
 447 CompileWrapper::CompileWrapper(Compile* compile) : _compile(compile) {
 448   // the Compile* pointer is stored in the current ciEnv:
 449   ciEnv* env = compile->env();
 450   assert(env == ciEnv::current(), "must already be a ciEnv active");
 451   assert(env->compiler_data() == NULL, "compile already active?");
 452   env->set_compiler_data(compile);
 453   assert(compile == Compile::current(), "sanity");
 454 
 455   compile->set_type_dict(NULL);
 456   compile->set_type_hwm(NULL);
 457   compile->set_type_last_size(0);
 458   compile->set_last_tf(NULL, NULL);
 459   compile->set_indexSet_arena(NULL);
 460   compile->set_indexSet_free_block_list(NULL);
 461   compile->init_type_arena();
 462   Type::Initialize(compile);
 463   _compile->set_scratch_buffer_blob(NULL);
 464   _compile->begin_method();
 465 }
 466 CompileWrapper::~CompileWrapper() {
 467   _compile->end_method();
 468   if (_compile->scratch_buffer_blob() != NULL)
 469     BufferBlob::free(_compile->scratch_buffer_blob());
 470   _compile->env()->set_compiler_data(NULL);
 471 }
 472 
 473 
 474 //----------------------------print_compile_messages---------------------------
 475 void Compile::print_compile_messages() {
 476 #ifndef PRODUCT
 477   // Check if recompiling
 478   if (_subsume_loads == false && PrintOpto) {
 479     // Recompiling without allowing machine instructions to subsume loads
 480     tty->print_cr("*********************************************************");
 481     tty->print_cr("** Bailout: Recompile without subsuming loads          **");
 482     tty->print_cr("*********************************************************");
 483   }
 484   if (_do_escape_analysis != DoEscapeAnalysis && PrintOpto) {
 485     // Recompiling without escape analysis
 486     tty->print_cr("*********************************************************");
 487     tty->print_cr("** Bailout: Recompile without escape analysis          **");
 488     tty->print_cr("*********************************************************");
 489   }
 490   if (_eliminate_boxing != EliminateAutoBox && PrintOpto) {
 491     // Recompiling without boxing elimination
 492     tty->print_cr("*********************************************************");
 493     tty->print_cr("** Bailout: Recompile without boxing elimination       **");
 494     tty->print_cr("*********************************************************");
 495   }
 496   if (env()->break_at_compile()) {
 497     // Open the debugger when compiling this method.
 498     tty->print("### Breaking when compiling: ");
 499     method()->print_short_name();
 500     tty->cr();
 501     BREAKPOINT;
 502   }
 503 
 504   if( PrintOpto ) {
 505     if (is_osr_compilation()) {
 506       tty->print("[OSR]%3d", _compile_id);
 507     } else {
 508       tty->print("%3d", _compile_id);
 509     }
 510   }
 511 #endif
 512 }
 513 
 514 
 515 //-----------------------init_scratch_buffer_blob------------------------------
 516 // Construct a temporary BufferBlob and cache it for this compile.
 517 void Compile::init_scratch_buffer_blob(int const_size) {
 518   // If there is already a scratch buffer blob allocated and the
 519   // constant section is big enough, use it.  Otherwise free the
 520   // current and allocate a new one.
 521   BufferBlob* blob = scratch_buffer_blob();
 522   if ((blob != NULL) && (const_size <= _scratch_const_size)) {
 523     // Use the current blob.
 524   } else {
 525     if (blob != NULL) {
 526       BufferBlob::free(blob);
 527     }
 528 
 529     ResourceMark rm;
 530     _scratch_const_size = const_size;
 531     int size = (MAX_inst_size + MAX_stubs_size + _scratch_const_size);
 532     blob = BufferBlob::create("Compile::scratch_buffer", size);
 533     // Record the buffer blob for next time.
 534     set_scratch_buffer_blob(blob);
 535     // Have we run out of code space?
 536     if (scratch_buffer_blob() == NULL) {
 537       // Let CompilerBroker disable further compilations.
 538       record_failure("Not enough space for scratch buffer in CodeCache");
 539       return;
 540     }
 541   }
 542 
 543   // Initialize the relocation buffers
 544   relocInfo* locs_buf = (relocInfo*) blob->content_end() - MAX_locs_size;
 545   set_scratch_locs_memory(locs_buf);
 546 }
 547 
 548 
 549 //-----------------------scratch_emit_size-------------------------------------
 550 // Helper function that computes size by emitting code
 551 uint Compile::scratch_emit_size(const Node* n) {
 552   // Start scratch_emit_size section.
 553   set_in_scratch_emit_size(true);
 554 
 555   // Emit into a trash buffer and count bytes emitted.
 556   // This is a pretty expensive way to compute a size,
 557   // but it works well enough if seldom used.
 558   // All common fixed-size instructions are given a size
 559   // method by the AD file.
 560   // Note that the scratch buffer blob and locs memory are
 561   // allocated at the beginning of the compile task, and
 562   // may be shared by several calls to scratch_emit_size.
 563   // The allocation of the scratch buffer blob is particularly
 564   // expensive, since it has to grab the code cache lock.
 565   BufferBlob* blob = this->scratch_buffer_blob();
 566   assert(blob != NULL, "Initialize BufferBlob at start");
 567   assert(blob->size() > MAX_inst_size, "sanity");
 568   relocInfo* locs_buf = scratch_locs_memory();
 569   address blob_begin = blob->content_begin();
 570   address blob_end   = (address)locs_buf;
 571   assert(blob->content_contains(blob_end), "sanity");
 572   CodeBuffer buf(blob_begin, blob_end - blob_begin);
 573   buf.initialize_consts_size(_scratch_const_size);
 574   buf.initialize_stubs_size(MAX_stubs_size);
 575   assert(locs_buf != NULL, "sanity");
 576   int lsize = MAX_locs_size / 3;
 577   buf.consts()->initialize_shared_locs(&locs_buf[lsize * 0], lsize);
 578   buf.insts()->initialize_shared_locs( &locs_buf[lsize * 1], lsize);
 579   buf.stubs()->initialize_shared_locs( &locs_buf[lsize * 2], lsize);
 580 
 581   // Do the emission.
 582 
 583   Label fakeL; // Fake label for branch instructions.
 584   Label*   saveL = NULL;
 585   uint save_bnum = 0;
 586   bool is_branch = n->is_MachBranch();
 587   if (is_branch) {
 588     MacroAssembler masm(&buf);
 589     masm.bind(fakeL);
 590     n->as_MachBranch()->save_label(&saveL, &save_bnum);
 591     n->as_MachBranch()->label_set(&fakeL, 0);
 592   }
 593   n->emit(buf, this->regalloc());
 594   if (is_branch) // Restore label.
 595     n->as_MachBranch()->label_set(saveL, save_bnum);
 596 
 597   // End scratch_emit_size section.
 598   set_in_scratch_emit_size(false);
 599 
 600   return buf.insts_size();
 601 }
 602 
 603 
 604 // ============================================================================
 605 //------------------------------Compile standard-------------------------------
 606 debug_only( int Compile::_debug_idx = 100000; )
 607 
 608 // Compile a method.  entry_bci is -1 for normal compilations and indicates
 609 // the continuation bci for on stack replacement.
 610 
 611 
 612 Compile::Compile( ciEnv* ci_env, C2Compiler* compiler, ciMethod* target, int osr_bci,
 613                   bool subsume_loads, bool do_escape_analysis, bool eliminate_boxing )
 614                 : Phase(Compiler),
 615                   _env(ci_env),
 616                   _log(ci_env->log()),
 617                   _compile_id(ci_env->compile_id()),
 618                   _save_argument_registers(false),
 619                   _stub_name(NULL),
 620                   _stub_function(NULL),
 621                   _stub_entry_point(NULL),
 622                   _method(target),
 623                   _entry_bci(osr_bci),
 624                   _initial_gvn(NULL),
 625                   _for_igvn(NULL),
 626                   _warm_calls(NULL),
 627                   _subsume_loads(subsume_loads),
 628                   _do_escape_analysis(do_escape_analysis),
 629                   _eliminate_boxing(eliminate_boxing),
 630                   _failure_reason(NULL),
 631                   _code_buffer("Compile::Fill_buffer"),
 632                   _orig_pc_slot(0),
 633                   _orig_pc_slot_offset_in_bytes(0),
 634                   _has_method_handle_invokes(false),
 635                   _mach_constant_base_node(NULL),
 636                   _node_bundling_limit(0),
 637                   _node_bundling_base(NULL),
 638                   _java_calls(0),
 639                   _inner_loops(0),
 640                   _scratch_const_size(-1),
 641                   _in_scratch_emit_size(false),
 642                   _dead_node_list(comp_arena()),
 643                   _dead_node_count(0),
 644 #ifndef PRODUCT
 645                   _trace_opto_output(TraceOptoOutput || method()->has_option("TraceOptoOutput")),
 646                   _in_dump_cnt(0),
 647                   _printer(IdealGraphPrinter::printer()),
 648 #endif
 649                   _congraph(NULL),
 650                   _comp_arena(mtCompiler),
 651                   _node_arena(mtCompiler),
 652                   _old_arena(mtCompiler),
 653                   _Compile_types(mtCompiler),
 654                   _replay_inline_data(NULL),
 655                   _late_inlines(comp_arena(), 2, 0, NULL),
 656                   _string_late_inlines(comp_arena(), 2, 0, NULL),
 657                   _boxing_late_inlines(comp_arena(), 2, 0, NULL),
 658                   _late_inlines_pos(0),
 659                   _number_of_mh_late_inlines(0),
 660                   _inlining_progress(false),
 661                   _inlining_incrementally(false),
 662                   _print_inlining_list(NULL),
 663                   _print_inlining_stream(NULL),
 664                   _print_inlining_idx(0),
 665                   _print_inlining_output(NULL),
 666                   _interpreter_frame_size(0),
 667                   _max_node_limit(MaxNodeLimit) {
 668   C = this;
 669 
 670   CompileWrapper cw(this);
 671 
 672   if (CITimeVerbose) {
 673     tty->print(" ");
 674     target->holder()->name()->print();
 675     tty->print(".");
 676     target->print_short_name();
 677     tty->print("  ");
 678   }
 679   TraceTime t1("Total compilation time", &_t_totalCompilation, CITime, CITimeVerbose);
 680   TraceTime t2(NULL, &_t_methodCompilation, CITime, false);
 681 
 682 #ifndef PRODUCT
 683   bool print_opto_assembly = PrintOptoAssembly || _method->has_option("PrintOptoAssembly");
 684   if (!print_opto_assembly) {
 685     bool print_assembly = (PrintAssembly || _method->should_print_assembly());
 686     if (print_assembly && !Disassembler::can_decode()) {
 687       tty->print_cr("PrintAssembly request changed to PrintOptoAssembly");
 688       print_opto_assembly = true;
 689     }
 690   }
 691   set_print_assembly(print_opto_assembly);
 692   set_parsed_irreducible_loop(false);
 693 
 694   if (method()->has_option("ReplayInline")) {
 695     _replay_inline_data = ciReplay::load_inline_data(method(), entry_bci(), ci_env->comp_level());
 696   }
 697 #endif
 698   set_print_inlining(PrintInlining || method()->has_option("PrintInlining") NOT_PRODUCT( || PrintOptoInlining));
 699   set_print_intrinsics(PrintIntrinsics || method()->has_option("PrintIntrinsics"));
 700   set_has_irreducible_loop(true); // conservative until build_loop_tree() reset it
 701 
 702   if (ProfileTraps RTM_OPT_ONLY( || UseRTMLocking )) {
 703     // Make sure the method being compiled gets its own MDO,
 704     // so we can at least track the decompile_count().
 705     // Need MDO to record RTM code generation state.
 706     method()->ensure_method_data();
 707   }
 708 
 709   Init(::AliasLevel);
 710 
 711 
 712   print_compile_messages();
 713 
 714   _ilt = InlineTree::build_inline_tree_root();
 715 
 716   // Even if NO memory addresses are used, MergeMem nodes must have at least 1 slice
 717   assert(num_alias_types() >= AliasIdxRaw, "");
 718 
 719 #define MINIMUM_NODE_HASH  1023
 720   // Node list that Iterative GVN will start with
 721   Unique_Node_List for_igvn(comp_arena());
 722   set_for_igvn(&for_igvn);
 723 
 724   // GVN that will be run immediately on new nodes
 725   uint estimated_size = method()->code_size()*4+64;
 726   estimated_size = (estimated_size < MINIMUM_NODE_HASH ? MINIMUM_NODE_HASH : estimated_size);
 727   PhaseGVN gvn(node_arena(), estimated_size);
 728   set_initial_gvn(&gvn);
 729 
 730   print_inlining_init();
 731   { // Scope for timing the parser
 732     TracePhase tp("parse", &timers[_t_parser]);
 733 
 734     // Put top into the hash table ASAP.
 735     initial_gvn()->transform_no_reclaim(top());
 736 
 737     // Set up tf(), start(), and find a CallGenerator.
 738     CallGenerator* cg = NULL;
 739     if (is_osr_compilation()) {
 740       const TypeTuple *domain = StartOSRNode::osr_domain();
 741       const TypeTuple *range = TypeTuple::make_range(method()->signature());
 742       init_tf(TypeFunc::make(domain, range));
 743       StartNode* s = new StartOSRNode(root(), domain);
 744       initial_gvn()->set_type_bottom(s);
 745       init_start(s);
 746       cg = CallGenerator::for_osr(method(), entry_bci());
 747     } else {
 748       // Normal case.
 749       init_tf(TypeFunc::make(method()));
 750       StartNode* s = new StartNode(root(), tf()->domain());
 751       initial_gvn()->set_type_bottom(s);
 752       init_start(s);
 753       if (method()->intrinsic_id() == vmIntrinsics::_Reference_get && UseG1GC) {
 754         // With java.lang.ref.reference.get() we must go through the
 755         // intrinsic when G1 is enabled - even when get() is the root
 756         // method of the compile - so that, if necessary, the value in
 757         // the referent field of the reference object gets recorded by
 758         // the pre-barrier code.
 759         // Specifically, if G1 is enabled, the value in the referent
 760         // field is recorded by the G1 SATB pre barrier. This will
 761         // result in the referent being marked live and the reference
 762         // object removed from the list of discovered references during
 763         // reference processing.
 764         cg = find_intrinsic(method(), false);
 765       }
 766       if (cg == NULL) {
 767         float past_uses = method()->interpreter_invocation_count();
 768         float expected_uses = past_uses;
 769         cg = CallGenerator::for_inline(method(), expected_uses);
 770       }
 771     }
 772     if (failing())  return;
 773     if (cg == NULL) {
 774       record_method_not_compilable_all_tiers("cannot parse method");
 775       return;
 776     }
 777     JVMState* jvms = build_start_state(start(), tf());
 778     if ((jvms = cg->generate(jvms)) == NULL) {
 779       if (!failure_reason_is(C2Compiler::retry_class_loading_during_parsing())) {
 780         record_method_not_compilable("method parse failed");
 781       }
 782       return;
 783     }
 784     GraphKit kit(jvms);
 785 
 786     if (!kit.stopped()) {
 787       // Accept return values, and transfer control we know not where.
 788       // This is done by a special, unique ReturnNode bound to root.
 789       return_values(kit.jvms());
 790     }
 791 
 792     if (kit.has_exceptions()) {
 793       // Any exceptions that escape from this call must be rethrown
 794       // to whatever caller is dynamically above us on the stack.
 795       // This is done by a special, unique RethrowNode bound to root.
 796       rethrow_exceptions(kit.transfer_exceptions_into_jvms());
 797     }
 798 
 799     assert(IncrementalInline || (_late_inlines.length() == 0 && !has_mh_late_inlines()), "incremental inlining is off");
 800 
 801     if (_late_inlines.length() == 0 && !has_mh_late_inlines() && !failing() && has_stringbuilder()) {
 802       inline_string_calls(true);
 803     }
 804 
 805     if (failing())  return;
 806 
 807     print_method(PHASE_BEFORE_REMOVEUSELESS, 3);
 808 
 809     // Remove clutter produced by parsing.
 810     if (!failing()) {
 811       ResourceMark rm;
 812       PhaseRemoveUseless pru(initial_gvn(), &for_igvn);
 813     }
 814   }
 815 
 816   // Note:  Large methods are capped off in do_one_bytecode().
 817   if (failing())  return;
 818 
 819   // After parsing, node notes are no longer automagic.
 820   // They must be propagated by register_new_node_with_optimizer(),
 821   // clone(), or the like.
 822   set_default_node_notes(NULL);
 823 
 824   for (;;) {
 825     int successes = Inline_Warm();
 826     if (failing())  return;
 827     if (successes == 0)  break;
 828   }
 829 
 830   // Drain the list.
 831   Finish_Warm();
 832 #ifndef PRODUCT
 833   if (_printer && _printer->should_print(_method)) {
 834     _printer->print_inlining(this);
 835   }
 836 #endif
 837 
 838   if (failing())  return;
 839   NOT_PRODUCT( verify_graph_edges(); )
 840 
 841   // Now optimize
 842   Optimize();
 843   if (failing())  return;
 844   NOT_PRODUCT( verify_graph_edges(); )
 845 
 846 #ifndef PRODUCT
 847   if (PrintIdeal) {
 848     ttyLocker ttyl;  // keep the following output all in one block
 849     // This output goes directly to the tty, not the compiler log.
 850     // To enable tools to match it up with the compilation activity,
 851     // be sure to tag this tty output with the compile ID.
 852     if (xtty != NULL) {
 853       xtty->head("ideal compile_id='%d'%s", compile_id(),
 854                  is_osr_compilation()    ? " compile_kind='osr'" :
 855                  "");
 856     }
 857     root()->dump(9999);
 858     if (xtty != NULL) {
 859       xtty->tail("ideal");
 860     }
 861   }
 862 #endif
 863 
 864   NOT_PRODUCT( verify_barriers(); )
 865 
 866   // Dump compilation data to replay it.
 867   if (method()->has_option("DumpReplay")) {
 868     env()->dump_replay_data(_compile_id);
 869   }
 870   if (method()->has_option("DumpInline") && (ilt() != NULL)) {
 871     env()->dump_inline_data(_compile_id);
 872   }
 873 
 874   // Now that we know the size of all the monitors we can add a fixed slot
 875   // for the original deopt pc.
 876 
 877   _orig_pc_slot =  fixed_slots();
 878   int next_slot = _orig_pc_slot + (sizeof(address) / VMRegImpl::stack_slot_size);
 879   set_fixed_slots(next_slot);
 880 
 881   // Compute when to use implicit null checks. Used by matching trap based
 882   // nodes and NullCheck optimization.
 883   set_allowed_deopt_reasons();
 884 
 885   // Now generate code
 886   Code_Gen();
 887   if (failing())  return;
 888 
 889   // Check if we want to skip execution of all compiled code.
 890   {
 891 #ifndef PRODUCT
 892     if (OptoNoExecute) {
 893       record_method_not_compilable("+OptoNoExecute");  // Flag as failed
 894       return;
 895     }
 896 #endif
 897     TracePhase tp("install_code", &timers[_t_registerMethod]);
 898 
 899     if (is_osr_compilation()) {
 900       _code_offsets.set_value(CodeOffsets::Verified_Entry, 0);
 901       _code_offsets.set_value(CodeOffsets::OSR_Entry, _first_block_size);
 902     } else {
 903       _code_offsets.set_value(CodeOffsets::Verified_Entry, _first_block_size);
 904       _code_offsets.set_value(CodeOffsets::OSR_Entry, 0);
 905     }
 906 
 907     env()->register_method(_method, _entry_bci,
 908                            &_code_offsets,
 909                            _orig_pc_slot_offset_in_bytes,
 910                            code_buffer(),
 911                            frame_size_in_words(), _oop_map_set,
 912                            &_handler_table, &_inc_table,
 913                            compiler,
 914                            env()->comp_level(),
 915                            has_unsafe_access(),
 916                            SharedRuntime::is_wide_vector(max_vector_size()),
 917                            rtm_state()
 918                            );
 919 
 920     if (log() != NULL) // Print code cache state into compiler log
 921       log()->code_cache_state();
 922   }
 923 }
 924 
 925 //------------------------------Compile----------------------------------------
 926 // Compile a runtime stub
 927 Compile::Compile( ciEnv* ci_env,
 928                   TypeFunc_generator generator,
 929                   address stub_function,
 930                   const char *stub_name,
 931                   int is_fancy_jump,
 932                   bool pass_tls,
 933                   bool save_arg_registers,
 934                   bool return_pc )
 935   : Phase(Compiler),
 936     _env(ci_env),
 937     _log(ci_env->log()),
 938     _compile_id(0),
 939     _save_argument_registers(save_arg_registers),
 940     _method(NULL),
 941     _stub_name(stub_name),
 942     _stub_function(stub_function),
 943     _stub_entry_point(NULL),
 944     _entry_bci(InvocationEntryBci),
 945     _initial_gvn(NULL),
 946     _for_igvn(NULL),
 947     _warm_calls(NULL),
 948     _orig_pc_slot(0),
 949     _orig_pc_slot_offset_in_bytes(0),
 950     _subsume_loads(true),
 951     _do_escape_analysis(false),
 952     _eliminate_boxing(false),
 953     _failure_reason(NULL),
 954     _code_buffer("Compile::Fill_buffer"),
 955     _has_method_handle_invokes(false),
 956     _mach_constant_base_node(NULL),
 957     _node_bundling_limit(0),
 958     _node_bundling_base(NULL),
 959     _java_calls(0),
 960     _inner_loops(0),
 961 #ifndef PRODUCT
 962     _trace_opto_output(TraceOptoOutput),
 963     _in_dump_cnt(0),
 964     _printer(NULL),
 965 #endif
 966     _comp_arena(mtCompiler),
 967     _node_arena(mtCompiler),
 968     _old_arena(mtCompiler),
 969     _Compile_types(mtCompiler),
 970     _dead_node_list(comp_arena()),
 971     _dead_node_count(0),
 972     _congraph(NULL),
 973     _replay_inline_data(NULL),
 974     _number_of_mh_late_inlines(0),
 975     _inlining_progress(false),
 976     _inlining_incrementally(false),
 977     _print_inlining_list(NULL),
 978     _print_inlining_stream(NULL),
 979     _print_inlining_idx(0),
 980     _print_inlining_output(NULL),
 981     _allowed_reasons(0),
 982     _interpreter_frame_size(0),
 983     _max_node_limit(MaxNodeLimit) {
 984   C = this;
 985 
 986   TraceTime t1(NULL, &_t_totalCompilation, CITime, false);
 987   TraceTime t2(NULL, &_t_stubCompilation, CITime, false);
 988 
 989 #ifndef PRODUCT
 990   set_print_assembly(PrintFrameConverterAssembly);
 991   set_parsed_irreducible_loop(false);
 992 #endif
 993   set_has_irreducible_loop(false); // no loops
 994 
 995   CompileWrapper cw(this);
 996   Init(/*AliasLevel=*/ 0);
 997   init_tf((*generator)());
 998 
 999   {
1000     // The following is a dummy for the sake of GraphKit::gen_stub
1001     Unique_Node_List for_igvn(comp_arena());
1002     set_for_igvn(&for_igvn);  // not used, but some GraphKit guys push on this
1003     PhaseGVN gvn(Thread::current()->resource_area(),255);
1004     set_initial_gvn(&gvn);    // not significant, but GraphKit guys use it pervasively
1005     gvn.transform_no_reclaim(top());
1006 
1007     GraphKit kit;
1008     kit.gen_stub(stub_function, stub_name, is_fancy_jump, pass_tls, return_pc);
1009   }
1010 
1011   NOT_PRODUCT( verify_graph_edges(); )
1012   Code_Gen();
1013   if (failing())  return;
1014 
1015 
1016   // Entry point will be accessed using compile->stub_entry_point();
1017   if (code_buffer() == NULL) {
1018     Matcher::soft_match_failure();
1019   } else {
1020     if (PrintAssembly && (WizardMode || Verbose))
1021       tty->print_cr("### Stub::%s", stub_name);
1022 
1023     if (!failing()) {
1024       assert(_fixed_slots == 0, "no fixed slots used for runtime stubs");
1025 
1026       // Make the NMethod
1027       // For now we mark the frame as never safe for profile stackwalking
1028       RuntimeStub *rs = RuntimeStub::new_runtime_stub(stub_name,
1029                                                       code_buffer(),
1030                                                       CodeOffsets::frame_never_safe,
1031                                                       // _code_offsets.value(CodeOffsets::Frame_Complete),
1032                                                       frame_size_in_words(),
1033                                                       _oop_map_set,
1034                                                       save_arg_registers);
1035       assert(rs != NULL && rs->is_runtime_stub(), "sanity check");
1036 
1037       _stub_entry_point = rs->entry_point();
1038     }
1039   }
1040 }
1041 
1042 //------------------------------Init-------------------------------------------
1043 // Prepare for a single compilation
1044 void Compile::Init(int aliaslevel) {
1045   _unique  = 0;
1046   _regalloc = NULL;
1047 
1048   _tf      = NULL;  // filled in later
1049   _top     = NULL;  // cached later
1050   _matcher = NULL;  // filled in later
1051   _cfg     = NULL;  // filled in later
1052 
1053   set_24_bit_selection_and_mode(Use24BitFP, false);
1054 
1055   _node_note_array = NULL;
1056   _default_node_notes = NULL;
1057   DEBUG_ONLY( _modified_nodes = NULL; ) // Used in Optimize()
1058 
1059   _immutable_memory = NULL; // filled in at first inquiry
1060 
1061   // Globally visible Nodes
1062   // First set TOP to NULL to give safe behavior during creation of RootNode
1063   set_cached_top_node(NULL);
1064   set_root(new RootNode());
1065   // Now that you have a Root to point to, create the real TOP
1066   set_cached_top_node( new ConNode(Type::TOP) );
1067   set_recent_alloc(NULL, NULL);
1068 
1069   // Create Debug Information Recorder to record scopes, oopmaps, etc.
1070   env()->set_oop_recorder(new OopRecorder(env()->arena()));
1071   env()->set_debug_info(new DebugInformationRecorder(env()->oop_recorder()));
1072   env()->set_dependencies(new Dependencies(env()));
1073 
1074   _fixed_slots = 0;
1075   set_has_split_ifs(false);
1076   set_has_loops(has_method() && method()->has_loops()); // first approximation
1077   set_has_stringbuilder(false);
1078   set_has_boxed_value(false);
1079   _trap_can_recompile = false;  // no traps emitted yet
1080   _major_progress = true; // start out assuming good things will happen
1081   set_has_unsafe_access(false);
1082   set_max_vector_size(0);
1083   Copy::zero_to_bytes(_trap_hist, sizeof(_trap_hist));
1084   set_decompile_count(0);
1085 
1086   set_do_freq_based_layout(BlockLayoutByFrequency || method_has_option("BlockLayoutByFrequency"));
1087   set_num_loop_opts(LoopOptsCount);
1088   set_do_inlining(Inline);
1089   set_max_inline_size(MaxInlineSize);
1090   set_freq_inline_size(FreqInlineSize);
1091   set_do_scheduling(OptoScheduling);
1092   set_do_count_invocations(false);
1093   set_do_method_data_update(false);
1094   set_age_code(has_method() && method()->profile_aging());
1095   set_rtm_state(NoRTM); // No RTM lock eliding by default
1096   method_has_option_value("MaxNodeLimit", _max_node_limit);
1097 #if INCLUDE_RTM_OPT
1098   if (UseRTMLocking && has_method() && (method()->method_data_or_null() != NULL)) {
1099     int rtm_state = method()->method_data()->rtm_state();
1100     if (method_has_option("NoRTMLockEliding") || ((rtm_state & NoRTM) != 0)) {
1101       // Don't generate RTM lock eliding code.
1102       set_rtm_state(NoRTM);
1103     } else if (method_has_option("UseRTMLockEliding") || ((rtm_state & UseRTM) != 0) || !UseRTMDeopt) {
1104       // Generate RTM lock eliding code without abort ratio calculation code.
1105       set_rtm_state(UseRTM);
1106     } else if (UseRTMDeopt) {
1107       // Generate RTM lock eliding code and include abort ratio calculation
1108       // code if UseRTMDeopt is on.
1109       set_rtm_state(ProfileRTM);
1110     }
1111   }
1112 #endif
1113   if (debug_info()->recording_non_safepoints()) {
1114     set_node_note_array(new(comp_arena()) GrowableArray<Node_Notes*>
1115                         (comp_arena(), 8, 0, NULL));
1116     set_default_node_notes(Node_Notes::make(this));
1117   }
1118 
1119   // // -- Initialize types before each compile --
1120   // // Update cached type information
1121   // if( _method && _method->constants() )
1122   //   Type::update_loaded_types(_method, _method->constants());
1123 
1124   // Init alias_type map.
1125   if (!_do_escape_analysis && aliaslevel == 3)
1126     aliaslevel = 2;  // No unique types without escape analysis
1127   _AliasLevel = aliaslevel;
1128   const int grow_ats = 16;
1129   _max_alias_types = grow_ats;
1130   _alias_types   = NEW_ARENA_ARRAY(comp_arena(), AliasType*, grow_ats);
1131   AliasType* ats = NEW_ARENA_ARRAY(comp_arena(), AliasType,  grow_ats);
1132   Copy::zero_to_bytes(ats, sizeof(AliasType)*grow_ats);
1133   {
1134     for (int i = 0; i < grow_ats; i++)  _alias_types[i] = &ats[i];
1135   }
1136   // Initialize the first few types.
1137   _alias_types[AliasIdxTop]->Init(AliasIdxTop, NULL);
1138   _alias_types[AliasIdxBot]->Init(AliasIdxBot, TypePtr::BOTTOM);
1139   _alias_types[AliasIdxRaw]->Init(AliasIdxRaw, TypeRawPtr::BOTTOM);
1140   _num_alias_types = AliasIdxRaw+1;
1141   // Zero out the alias type cache.
1142   Copy::zero_to_bytes(_alias_cache, sizeof(_alias_cache));
1143   // A NULL adr_type hits in the cache right away.  Preload the right answer.
1144   probe_alias_cache(NULL)->_index = AliasIdxTop;
1145 
1146   _intrinsics = NULL;
1147   _macro_nodes = new(comp_arena()) GrowableArray<Node*>(comp_arena(), 8,  0, NULL);
1148   _predicate_opaqs = new(comp_arena()) GrowableArray<Node*>(comp_arena(), 8,  0, NULL);
1149   _expensive_nodes = new(comp_arena()) GrowableArray<Node*>(comp_arena(), 8,  0, NULL);
1150   register_library_intrinsics();
1151 }
1152 
1153 //---------------------------init_start----------------------------------------
1154 // Install the StartNode on this compile object.
1155 void Compile::init_start(StartNode* s) {
1156   if (failing())
1157     return; // already failing
1158   assert(s == start(), "");
1159 }
1160 
1161 /**
1162  * Return the 'StartNode'. We must not have a pending failure, since the ideal graph
1163  * can be in an inconsistent state, i.e., we can get segmentation faults when traversing
1164  * the ideal graph.
1165  */
1166 StartNode* Compile::start() const {
1167   assert (!failing(), err_msg_res("Must not have pending failure. Reason is: %s", failure_reason()));
1168   for (DUIterator_Fast imax, i = root()->fast_outs(imax); i < imax; i++) {
1169     Node* start = root()->fast_out(i);
1170     if (start->is_Start()) {
1171       return start->as_Start();
1172     }
1173   }
1174   fatal("Did not find Start node!");
1175   return NULL;
1176 }
1177 
1178 //-------------------------------immutable_memory-------------------------------------
1179 // Access immutable memory
1180 Node* Compile::immutable_memory() {
1181   if (_immutable_memory != NULL) {
1182     return _immutable_memory;
1183   }
1184   StartNode* s = start();
1185   for (DUIterator_Fast imax, i = s->fast_outs(imax); true; i++) {
1186     Node *p = s->fast_out(i);
1187     if (p != s && p->as_Proj()->_con == TypeFunc::Memory) {
1188       _immutable_memory = p;
1189       return _immutable_memory;
1190     }
1191   }
1192   ShouldNotReachHere();
1193   return NULL;
1194 }
1195 
1196 //----------------------set_cached_top_node------------------------------------
1197 // Install the cached top node, and make sure Node::is_top works correctly.
1198 void Compile::set_cached_top_node(Node* tn) {
1199   if (tn != NULL)  verify_top(tn);
1200   Node* old_top = _top;
1201   _top = tn;
1202   // Calling Node::setup_is_top allows the nodes the chance to adjust
1203   // their _out arrays.
1204   if (_top != NULL)     _top->setup_is_top();
1205   if (old_top != NULL)  old_top->setup_is_top();
1206   assert(_top == NULL || top()->is_top(), "");
1207 }
1208 
1209 #ifdef ASSERT
1210 uint Compile::count_live_nodes_by_graph_walk() {
1211   Unique_Node_List useful(comp_arena());
1212   // Get useful node list by walking the graph.
1213   identify_useful_nodes(useful);
1214   return useful.size();
1215 }
1216 
1217 void Compile::print_missing_nodes() {
1218 
1219   // Return if CompileLog is NULL and PrintIdealNodeCount is false.
1220   if ((_log == NULL) && (! PrintIdealNodeCount)) {
1221     return;
1222   }
1223 
1224   // This is an expensive function. It is executed only when the user
1225   // specifies VerifyIdealNodeCount option or otherwise knows the
1226   // additional work that needs to be done to identify reachable nodes
1227   // by walking the flow graph and find the missing ones using
1228   // _dead_node_list.
1229 
1230   Unique_Node_List useful(comp_arena());
1231   // Get useful node list by walking the graph.
1232   identify_useful_nodes(useful);
1233 
1234   uint l_nodes = C->live_nodes();
1235   uint l_nodes_by_walk = useful.size();
1236 
1237   if (l_nodes != l_nodes_by_walk) {
1238     if (_log != NULL) {
1239       _log->begin_head("mismatched_nodes count='%d'", abs((int) (l_nodes - l_nodes_by_walk)));
1240       _log->stamp();
1241       _log->end_head();
1242     }
1243     VectorSet& useful_member_set = useful.member_set();
1244     int last_idx = l_nodes_by_walk;
1245     for (int i = 0; i < last_idx; i++) {
1246       if (useful_member_set.test(i)) {
1247         if (_dead_node_list.test(i)) {
1248           if (_log != NULL) {
1249             _log->elem("mismatched_node_info node_idx='%d' type='both live and dead'", i);
1250           }
1251           if (PrintIdealNodeCount) {
1252             // Print the log message to tty
1253               tty->print_cr("mismatched_node idx='%d' both live and dead'", i);
1254               useful.at(i)->dump();
1255           }
1256         }
1257       }
1258       else if (! _dead_node_list.test(i)) {
1259         if (_log != NULL) {
1260           _log->elem("mismatched_node_info node_idx='%d' type='neither live nor dead'", i);
1261         }
1262         if (PrintIdealNodeCount) {
1263           // Print the log message to tty
1264           tty->print_cr("mismatched_node idx='%d' type='neither live nor dead'", i);
1265         }
1266       }
1267     }
1268     if (_log != NULL) {
1269       _log->tail("mismatched_nodes");
1270     }
1271   }
1272 }
1273 void Compile::record_modified_node(Node* n) {
1274   if (_modified_nodes != NULL && !_inlining_incrementally &&
1275       n->outcnt() != 0 && !n->is_Con()) {
1276     _modified_nodes->push(n);
1277   }
1278 }
1279 
1280 void Compile::remove_modified_node(Node* n) {
1281   if (_modified_nodes != NULL) {
1282     _modified_nodes->remove(n);
1283   }
1284 }
1285 #endif
1286 
1287 #ifndef PRODUCT
1288 void Compile::verify_top(Node* tn) const {
1289   if (tn != NULL) {
1290     assert(tn->is_Con(), "top node must be a constant");
1291     assert(((ConNode*)tn)->type() == Type::TOP, "top node must have correct type");
1292     assert(tn->in(0) != NULL, "must have live top node");
1293   }
1294 }
1295 #endif
1296 
1297 
1298 ///-------------------Managing Per-Node Debug & Profile Info-------------------
1299 
1300 void Compile::grow_node_notes(GrowableArray<Node_Notes*>* arr, int grow_by) {
1301   guarantee(arr != NULL, "");
1302   int num_blocks = arr->length();
1303   if (grow_by < num_blocks)  grow_by = num_blocks;
1304   int num_notes = grow_by * _node_notes_block_size;
1305   Node_Notes* notes = NEW_ARENA_ARRAY(node_arena(), Node_Notes, num_notes);
1306   Copy::zero_to_bytes(notes, num_notes * sizeof(Node_Notes));
1307   while (num_notes > 0) {
1308     arr->append(notes);
1309     notes     += _node_notes_block_size;
1310     num_notes -= _node_notes_block_size;
1311   }
1312   assert(num_notes == 0, "exact multiple, please");
1313 }
1314 
1315 bool Compile::copy_node_notes_to(Node* dest, Node* source) {
1316   if (source == NULL || dest == NULL)  return false;
1317 
1318   if (dest->is_Con())
1319     return false;               // Do not push debug info onto constants.
1320 
1321 #ifdef ASSERT
1322   // Leave a bread crumb trail pointing to the original node:
1323   if (dest != NULL && dest != source && dest->debug_orig() == NULL) {
1324     dest->set_debug_orig(source);
1325   }
1326 #endif
1327 
1328   if (node_note_array() == NULL)
1329     return false;               // Not collecting any notes now.
1330 
1331   // This is a copy onto a pre-existing node, which may already have notes.
1332   // If both nodes have notes, do not overwrite any pre-existing notes.
1333   Node_Notes* source_notes = node_notes_at(source->_idx);
1334   if (source_notes == NULL || source_notes->is_clear())  return false;
1335   Node_Notes* dest_notes   = node_notes_at(dest->_idx);
1336   if (dest_notes == NULL || dest_notes->is_clear()) {
1337     return set_node_notes_at(dest->_idx, source_notes);
1338   }
1339 
1340   Node_Notes merged_notes = (*source_notes);
1341   // The order of operations here ensures that dest notes will win...
1342   merged_notes.update_from(dest_notes);
1343   return set_node_notes_at(dest->_idx, &merged_notes);
1344 }
1345 
1346 
1347 //--------------------------allow_range_check_smearing-------------------------
1348 // Gating condition for coalescing similar range checks.
1349 // Sometimes we try 'speculatively' replacing a series of a range checks by a
1350 // single covering check that is at least as strong as any of them.
1351 // If the optimization succeeds, the simplified (strengthened) range check
1352 // will always succeed.  If it fails, we will deopt, and then give up
1353 // on the optimization.
1354 bool Compile::allow_range_check_smearing() const {
1355   // If this method has already thrown a range-check,
1356   // assume it was because we already tried range smearing
1357   // and it failed.
1358   uint already_trapped = trap_count(Deoptimization::Reason_range_check);
1359   return !already_trapped;
1360 }
1361 
1362 
1363 //------------------------------flatten_alias_type-----------------------------
1364 const TypePtr *Compile::flatten_alias_type( const TypePtr *tj ) const {
1365   int offset = tj->offset();
1366   TypePtr::PTR ptr = tj->ptr();
1367 
1368   // Known instance (scalarizable allocation) alias only with itself.
1369   bool is_known_inst = tj->isa_oopptr() != NULL &&
1370                        tj->is_oopptr()->is_known_instance();
1371 
1372   // Process weird unsafe references.
1373   if (offset == Type::OffsetBot && (tj->isa_instptr() /*|| tj->isa_klassptr()*/)) {
1374     assert(InlineUnsafeOps, "indeterminate pointers come only from unsafe ops");
1375     assert(!is_known_inst, "scalarizable allocation should not have unsafe references");
1376     tj = TypeOopPtr::BOTTOM;
1377     ptr = tj->ptr();
1378     offset = tj->offset();
1379   }
1380 
1381   // Array pointers need some flattening
1382   const TypeAryPtr *ta = tj->isa_aryptr();
1383   if (ta && ta->is_stable()) {
1384     // Erase stability property for alias analysis.
1385     tj = ta = ta->cast_to_stable(false);
1386   }
1387   if( ta && is_known_inst ) {
1388     if ( offset != Type::OffsetBot &&
1389          offset > arrayOopDesc::length_offset_in_bytes() ) {
1390       offset = Type::OffsetBot; // Flatten constant access into array body only
1391       tj = ta = TypeAryPtr::make(ptr, ta->ary(), ta->klass(), true, offset, ta->instance_id());
1392     }
1393   } else if( ta && _AliasLevel >= 2 ) {
1394     // For arrays indexed by constant indices, we flatten the alias
1395     // space to include all of the array body.  Only the header, klass
1396     // and array length can be accessed un-aliased.
1397     if( offset != Type::OffsetBot ) {
1398       if( ta->const_oop() ) { // MethodData* or Method*
1399         offset = Type::OffsetBot;   // Flatten constant access into array body
1400         tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),ta->ary(),ta->klass(),false,offset);
1401       } else if( offset == arrayOopDesc::length_offset_in_bytes() ) {
1402         // range is OK as-is.
1403         tj = ta = TypeAryPtr::RANGE;
1404       } else if( offset == oopDesc::klass_offset_in_bytes() ) {
1405         tj = TypeInstPtr::KLASS; // all klass loads look alike
1406         ta = TypeAryPtr::RANGE; // generic ignored junk
1407         ptr = TypePtr::BotPTR;
1408       } else if( offset == oopDesc::mark_offset_in_bytes() ) {
1409         tj = TypeInstPtr::MARK;
1410         ta = TypeAryPtr::RANGE; // generic ignored junk
1411         ptr = TypePtr::BotPTR;
1412       } else {                  // Random constant offset into array body
1413         offset = Type::OffsetBot;   // Flatten constant access into array body
1414         tj = ta = TypeAryPtr::make(ptr,ta->ary(),ta->klass(),false,offset);
1415       }
1416     }
1417     // Arrays of fixed size alias with arrays of unknown size.
1418     if (ta->size() != TypeInt::POS) {
1419       const TypeAry *tary = TypeAry::make(ta->elem(), TypeInt::POS);
1420       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,ta->klass(),false,offset);
1421     }
1422     // Arrays of known objects become arrays of unknown objects.
1423     if (ta->elem()->isa_narrowoop() && ta->elem() != TypeNarrowOop::BOTTOM) {
1424       const TypeAry *tary = TypeAry::make(TypeNarrowOop::BOTTOM, ta->size());
1425       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,NULL,false,offset);
1426     }
1427     if (ta->elem()->isa_oopptr() && ta->elem() != TypeInstPtr::BOTTOM) {
1428       const TypeAry *tary = TypeAry::make(TypeInstPtr::BOTTOM, ta->size());
1429       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,NULL,false,offset);
1430     }
1431     // Arrays of bytes and of booleans both use 'bastore' and 'baload' so
1432     // cannot be distinguished by bytecode alone.
1433     if (ta->elem() == TypeInt::BOOL) {
1434       const TypeAry *tary = TypeAry::make(TypeInt::BYTE, ta->size());
1435       ciKlass* aklass = ciTypeArrayKlass::make(T_BYTE);
1436       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,aklass,false,offset);
1437     }
1438     // During the 2nd round of IterGVN, NotNull castings are removed.
1439     // Make sure the Bottom and NotNull variants alias the same.
1440     // Also, make sure exact and non-exact variants alias the same.
1441     if (ptr == TypePtr::NotNull || ta->klass_is_exact() || ta->speculative() != NULL) {
1442       tj = ta = TypeAryPtr::make(TypePtr::BotPTR,ta->ary(),ta->klass(),false,offset);
1443     }
1444   }
1445 
1446   // Oop pointers need some flattening
1447   const TypeInstPtr *to = tj->isa_instptr();
1448   if( to && _AliasLevel >= 2 && to != TypeOopPtr::BOTTOM ) {
1449     ciInstanceKlass *k = to->klass()->as_instance_klass();
1450     if( ptr == TypePtr::Constant ) {
1451       if (to->klass() != ciEnv::current()->Class_klass() ||
1452           offset < k->size_helper() * wordSize) {
1453         // No constant oop pointers (such as Strings); they alias with
1454         // unknown strings.
1455         assert(!is_known_inst, "not scalarizable allocation");
1456         tj = to = TypeInstPtr::make(TypePtr::BotPTR,to->klass(),false,0,offset);
1457       }
1458     } else if( is_known_inst ) {
1459       tj = to; // Keep NotNull and klass_is_exact for instance type
1460     } else if( ptr == TypePtr::NotNull || to->klass_is_exact() ) {
1461       // During the 2nd round of IterGVN, NotNull castings are removed.
1462       // Make sure the Bottom and NotNull variants alias the same.
1463       // Also, make sure exact and non-exact variants alias the same.
1464       tj = to = TypeInstPtr::make(TypePtr::BotPTR,to->klass(),false,0,offset);
1465     }
1466     if (to->speculative() != NULL) {
1467       tj = to = TypeInstPtr::make(to->ptr(),to->klass(),to->klass_is_exact(),to->const_oop(),to->offset(), to->instance_id());
1468     }
1469     // Canonicalize the holder of this field
1470     if (offset >= 0 && offset < instanceOopDesc::base_offset_in_bytes()) {
1471       // First handle header references such as a LoadKlassNode, even if the
1472       // object's klass is unloaded at compile time (4965979).
1473       if (!is_known_inst) { // Do it only for non-instance types
1474         tj = to = TypeInstPtr::make(TypePtr::BotPTR, env()->Object_klass(), false, NULL, offset);
1475       }
1476     } else if (offset < 0 || offset >= k->size_helper() * wordSize) {
1477       // Static fields are in the space above the normal instance
1478       // fields in the java.lang.Class instance.
1479       if (to->klass() != ciEnv::current()->Class_klass()) {
1480         to = NULL;
1481         tj = TypeOopPtr::BOTTOM;
1482         offset = tj->offset();
1483       }
1484     } else {
1485       ciInstanceKlass *canonical_holder = k->get_canonical_holder(offset);
1486       if (!k->equals(canonical_holder) || tj->offset() != offset) {
1487         if( is_known_inst ) {
1488           tj = to = TypeInstPtr::make(to->ptr(), canonical_holder, true, NULL, offset, to->instance_id());
1489         } else {
1490           tj = to = TypeInstPtr::make(to->ptr(), canonical_holder, false, NULL, offset);
1491         }
1492       }
1493     }
1494   }
1495 
1496   // Klass pointers to object array klasses need some flattening
1497   const TypeKlassPtr *tk = tj->isa_klassptr();
1498   if( tk ) {
1499     // If we are referencing a field within a Klass, we need
1500     // to assume the worst case of an Object.  Both exact and
1501     // inexact types must flatten to the same alias class so
1502     // use NotNull as the PTR.
1503     if ( offset == Type::OffsetBot || (offset >= 0 && (size_t)offset < sizeof(Klass)) ) {
1504 
1505       tj = tk = TypeKlassPtr::make(TypePtr::NotNull,
1506                                    TypeKlassPtr::OBJECT->klass(),
1507                                    offset);
1508     }
1509 
1510     ciKlass* klass = tk->klass();
1511     if( klass->is_obj_array_klass() ) {
1512       ciKlass* k = TypeAryPtr::OOPS->klass();
1513       if( !k || !k->is_loaded() )                  // Only fails for some -Xcomp runs
1514         k = TypeInstPtr::BOTTOM->klass();
1515       tj = tk = TypeKlassPtr::make( TypePtr::NotNull, k, offset );
1516     }
1517 
1518     // Check for precise loads from the primary supertype array and force them
1519     // to the supertype cache alias index.  Check for generic array loads from
1520     // the primary supertype array and also force them to the supertype cache
1521     // alias index.  Since the same load can reach both, we need to merge
1522     // these 2 disparate memories into the same alias class.  Since the
1523     // primary supertype array is read-only, there's no chance of confusion
1524     // where we bypass an array load and an array store.
1525     int primary_supers_offset = in_bytes(Klass::primary_supers_offset());
1526     if (offset == Type::OffsetBot ||
1527         (offset >= primary_supers_offset &&
1528          offset < (int)(primary_supers_offset + Klass::primary_super_limit() * wordSize)) ||
1529         offset == (int)in_bytes(Klass::secondary_super_cache_offset())) {
1530       offset = in_bytes(Klass::secondary_super_cache_offset());
1531       tj = tk = TypeKlassPtr::make( TypePtr::NotNull, tk->klass(), offset );
1532     }
1533   }
1534 
1535   // Flatten all Raw pointers together.
1536   if (tj->base() == Type::RawPtr)
1537     tj = TypeRawPtr::BOTTOM;
1538 
1539   if (tj->base() == Type::AnyPtr)
1540     tj = TypePtr::BOTTOM;      // An error, which the caller must check for.
1541 
1542   // Flatten all to bottom for now
1543   switch( _AliasLevel ) {
1544   case 0:
1545     tj = TypePtr::BOTTOM;
1546     break;
1547   case 1:                       // Flatten to: oop, static, field or array
1548     switch (tj->base()) {
1549     //case Type::AryPtr: tj = TypeAryPtr::RANGE;    break;
1550     case Type::RawPtr:   tj = TypeRawPtr::BOTTOM;   break;
1551     case Type::AryPtr:   // do not distinguish arrays at all
1552     case Type::InstPtr:  tj = TypeInstPtr::BOTTOM;  break;
1553     case Type::KlassPtr: tj = TypeKlassPtr::OBJECT; break;
1554     case Type::AnyPtr:   tj = TypePtr::BOTTOM;      break;  // caller checks it
1555     default: ShouldNotReachHere();
1556     }
1557     break;
1558   case 2:                       // No collapsing at level 2; keep all splits
1559   case 3:                       // No collapsing at level 3; keep all splits
1560     break;
1561   default:
1562     Unimplemented();
1563   }
1564 
1565   offset = tj->offset();
1566   assert( offset != Type::OffsetTop, "Offset has fallen from constant" );
1567 
1568   assert( (offset != Type::OffsetBot && tj->base() != Type::AryPtr) ||
1569           (offset == Type::OffsetBot && tj->base() == Type::AryPtr) ||
1570           (offset == Type::OffsetBot && tj == TypeOopPtr::BOTTOM) ||
1571           (offset == Type::OffsetBot && tj == TypePtr::BOTTOM) ||
1572           (offset == oopDesc::mark_offset_in_bytes() && tj->base() == Type::AryPtr) ||
1573           (offset == oopDesc::klass_offset_in_bytes() && tj->base() == Type::AryPtr) ||
1574           (offset == arrayOopDesc::length_offset_in_bytes() && tj->base() == Type::AryPtr)  ,
1575           "For oops, klasses, raw offset must be constant; for arrays the offset is never known" );
1576   assert( tj->ptr() != TypePtr::TopPTR &&
1577           tj->ptr() != TypePtr::AnyNull &&
1578           tj->ptr() != TypePtr::Null, "No imprecise addresses" );
1579 //    assert( tj->ptr() != TypePtr::Constant ||
1580 //            tj->base() == Type::RawPtr ||
1581 //            tj->base() == Type::KlassPtr, "No constant oop addresses" );
1582 
1583   return tj;
1584 }
1585 
1586 void Compile::AliasType::Init(int i, const TypePtr* at) {
1587   _index = i;
1588   _adr_type = at;
1589   _field = NULL;
1590   _element = NULL;
1591   _is_rewritable = true; // default
1592   const TypeOopPtr *atoop = (at != NULL) ? at->isa_oopptr() : NULL;
1593   if (atoop != NULL && atoop->is_known_instance()) {
1594     const TypeOopPtr *gt = atoop->cast_to_instance_id(TypeOopPtr::InstanceBot);
1595     _general_index = Compile::current()->get_alias_index(gt);
1596   } else {
1597     _general_index = 0;
1598   }
1599 }
1600 
1601 //---------------------------------print_on------------------------------------
1602 #ifndef PRODUCT
1603 void Compile::AliasType::print_on(outputStream* st) {
1604   if (index() < 10)
1605         st->print("@ <%d> ", index());
1606   else  st->print("@ <%d>",  index());
1607   st->print(is_rewritable() ? "   " : " RO");
1608   int offset = adr_type()->offset();
1609   if (offset == Type::OffsetBot)
1610         st->print(" +any");
1611   else  st->print(" +%-3d", offset);
1612   st->print(" in ");
1613   adr_type()->dump_on(st);
1614   const TypeOopPtr* tjp = adr_type()->isa_oopptr();
1615   if (field() != NULL && tjp) {
1616     if (tjp->klass()  != field()->holder() ||
1617         tjp->offset() != field()->offset_in_bytes()) {
1618       st->print(" != ");
1619       field()->print();
1620       st->print(" ***");
1621     }
1622   }
1623 }
1624 
1625 void print_alias_types() {
1626   Compile* C = Compile::current();
1627   tty->print_cr("--- Alias types, AliasIdxBot .. %d", C->num_alias_types()-1);
1628   for (int idx = Compile::AliasIdxBot; idx < C->num_alias_types(); idx++) {
1629     C->alias_type(idx)->print_on(tty);
1630     tty->cr();
1631   }
1632 }
1633 #endif
1634 
1635 
1636 //----------------------------probe_alias_cache--------------------------------
1637 Compile::AliasCacheEntry* Compile::probe_alias_cache(const TypePtr* adr_type) {
1638   intptr_t key = (intptr_t) adr_type;
1639   key ^= key >> logAliasCacheSize;
1640   return &_alias_cache[key & right_n_bits(logAliasCacheSize)];
1641 }
1642 
1643 
1644 //-----------------------------grow_alias_types--------------------------------
1645 void Compile::grow_alias_types() {
1646   const int old_ats  = _max_alias_types; // how many before?
1647   const int new_ats  = old_ats;          // how many more?
1648   const int grow_ats = old_ats+new_ats;  // how many now?
1649   _max_alias_types = grow_ats;
1650   _alias_types =  REALLOC_ARENA_ARRAY(comp_arena(), AliasType*, _alias_types, old_ats, grow_ats);
1651   AliasType* ats =    NEW_ARENA_ARRAY(comp_arena(), AliasType, new_ats);
1652   Copy::zero_to_bytes(ats, sizeof(AliasType)*new_ats);
1653   for (int i = 0; i < new_ats; i++)  _alias_types[old_ats+i] = &ats[i];
1654 }
1655 
1656 
1657 //--------------------------------find_alias_type------------------------------
1658 Compile::AliasType* Compile::find_alias_type(const TypePtr* adr_type, bool no_create, ciField* original_field) {
1659   if (_AliasLevel == 0)
1660     return alias_type(AliasIdxBot);
1661 
1662   AliasCacheEntry* ace = probe_alias_cache(adr_type);
1663   if (ace->_adr_type == adr_type) {
1664     return alias_type(ace->_index);
1665   }
1666 
1667   // Handle special cases.
1668   if (adr_type == NULL)             return alias_type(AliasIdxTop);
1669   if (adr_type == TypePtr::BOTTOM)  return alias_type(AliasIdxBot);
1670 
1671   // Do it the slow way.
1672   const TypePtr* flat = flatten_alias_type(adr_type);
1673 
1674 #ifdef ASSERT
1675   assert(flat == flatten_alias_type(flat), "idempotent");
1676   assert(flat != TypePtr::BOTTOM,     "cannot alias-analyze an untyped ptr");
1677   if (flat->isa_oopptr() && !flat->isa_klassptr()) {
1678     const TypeOopPtr* foop = flat->is_oopptr();
1679     // Scalarizable allocations have exact klass always.
1680     bool exact = !foop->klass_is_exact() || foop->is_known_instance();
1681     const TypePtr* xoop = foop->cast_to_exactness(exact)->is_ptr();
1682     assert(foop == flatten_alias_type(xoop), "exactness must not affect alias type");
1683   }
1684   assert(flat == flatten_alias_type(flat), "exact bit doesn't matter");
1685 #endif
1686 
1687   int idx = AliasIdxTop;
1688   for (int i = 0; i < num_alias_types(); i++) {
1689     if (alias_type(i)->adr_type() == flat) {
1690       idx = i;
1691       break;
1692     }
1693   }
1694 
1695   if (idx == AliasIdxTop) {
1696     if (no_create)  return NULL;
1697     // Grow the array if necessary.
1698     if (_num_alias_types == _max_alias_types)  grow_alias_types();
1699     // Add a new alias type.
1700     idx = _num_alias_types++;
1701     _alias_types[idx]->Init(idx, flat);
1702     if (flat == TypeInstPtr::KLASS)  alias_type(idx)->set_rewritable(false);
1703     if (flat == TypeAryPtr::RANGE)   alias_type(idx)->set_rewritable(false);
1704     if (flat->isa_instptr()) {
1705       if (flat->offset() == java_lang_Class::klass_offset_in_bytes()
1706           && flat->is_instptr()->klass() == env()->Class_klass())
1707         alias_type(idx)->set_rewritable(false);
1708     }
1709     if (flat->isa_aryptr()) {
1710 #ifdef ASSERT
1711       const int header_size_min  = arrayOopDesc::base_offset_in_bytes(T_BYTE);
1712       // (T_BYTE has the weakest alignment and size restrictions...)
1713       assert(flat->offset() < header_size_min, "array body reference must be OffsetBot");
1714 #endif
1715       if (flat->offset() == TypePtr::OffsetBot) {
1716         alias_type(idx)->set_element(flat->is_aryptr()->elem());
1717       }
1718     }
1719     if (flat->isa_klassptr()) {
1720       if (flat->offset() == in_bytes(Klass::super_check_offset_offset()))
1721         alias_type(idx)->set_rewritable(false);
1722       if (flat->offset() == in_bytes(Klass::modifier_flags_offset()))
1723         alias_type(idx)->set_rewritable(false);
1724       if (flat->offset() == in_bytes(Klass::access_flags_offset()))
1725         alias_type(idx)->set_rewritable(false);
1726       if (flat->offset() == in_bytes(Klass::java_mirror_offset()))
1727         alias_type(idx)->set_rewritable(false);
1728     }
1729     // %%% (We would like to finalize JavaThread::threadObj_offset(),
1730     // but the base pointer type is not distinctive enough to identify
1731     // references into JavaThread.)
1732 
1733     // Check for final fields.
1734     const TypeInstPtr* tinst = flat->isa_instptr();
1735     if (tinst && tinst->offset() >= instanceOopDesc::base_offset_in_bytes()) {
1736       ciField* field;
1737       if (tinst->const_oop() != NULL &&
1738           tinst->klass() == ciEnv::current()->Class_klass() &&
1739           tinst->offset() >= (tinst->klass()->as_instance_klass()->size_helper() * wordSize)) {
1740         // static field
1741         ciInstanceKlass* k = tinst->const_oop()->as_instance()->java_lang_Class_klass()->as_instance_klass();
1742         field = k->get_field_by_offset(tinst->offset(), true);
1743       } else {
1744         ciInstanceKlass *k = tinst->klass()->as_instance_klass();
1745         field = k->get_field_by_offset(tinst->offset(), false);
1746       }
1747       assert(field == NULL ||
1748              original_field == NULL ||
1749              (field->holder() == original_field->holder() &&
1750               field->offset() == original_field->offset() &&
1751               field->is_static() == original_field->is_static()), "wrong field?");
1752       // Set field() and is_rewritable() attributes.
1753       if (field != NULL)  alias_type(idx)->set_field(field);
1754     }
1755   }
1756 
1757   // Fill the cache for next time.
1758   ace->_adr_type = adr_type;
1759   ace->_index    = idx;
1760   assert(alias_type(adr_type) == alias_type(idx),  "type must be installed");
1761 
1762   // Might as well try to fill the cache for the flattened version, too.
1763   AliasCacheEntry* face = probe_alias_cache(flat);
1764   if (face->_adr_type == NULL) {
1765     face->_adr_type = flat;
1766     face->_index    = idx;
1767     assert(alias_type(flat) == alias_type(idx), "flat type must work too");
1768   }
1769 
1770   return alias_type(idx);
1771 }
1772 
1773 
1774 Compile::AliasType* Compile::alias_type(ciField* field) {
1775   const TypeOopPtr* t;
1776   if (field->is_static())
1777     t = TypeInstPtr::make(field->holder()->java_mirror());
1778   else
1779     t = TypeOopPtr::make_from_klass_raw(field->holder());
1780   AliasType* atp = alias_type(t->add_offset(field->offset_in_bytes()), field);
1781   assert((field->is_final() || field->is_stable()) == !atp->is_rewritable(), "must get the rewritable bits correct");
1782   return atp;
1783 }
1784 
1785 
1786 //------------------------------have_alias_type--------------------------------
1787 bool Compile::have_alias_type(const TypePtr* adr_type) {
1788   AliasCacheEntry* ace = probe_alias_cache(adr_type);
1789   if (ace->_adr_type == adr_type) {
1790     return true;
1791   }
1792 
1793   // Handle special cases.
1794   if (adr_type == NULL)             return true;
1795   if (adr_type == TypePtr::BOTTOM)  return true;
1796 
1797   return find_alias_type(adr_type, true, NULL) != NULL;
1798 }
1799 
1800 //-----------------------------must_alias--------------------------------------
1801 // True if all values of the given address type are in the given alias category.
1802 bool Compile::must_alias(const TypePtr* adr_type, int alias_idx) {
1803   if (alias_idx == AliasIdxBot)         return true;  // the universal category
1804   if (adr_type == NULL)                 return true;  // NULL serves as TypePtr::TOP
1805   if (alias_idx == AliasIdxTop)         return false; // the empty category
1806   if (adr_type->base() == Type::AnyPtr) return false; // TypePtr::BOTTOM or its twins
1807 
1808   // the only remaining possible overlap is identity
1809   int adr_idx = get_alias_index(adr_type);
1810   assert(adr_idx != AliasIdxBot && adr_idx != AliasIdxTop, "");
1811   assert(adr_idx == alias_idx ||
1812          (alias_type(alias_idx)->adr_type() != TypeOopPtr::BOTTOM
1813           && adr_type                       != TypeOopPtr::BOTTOM),
1814          "should not be testing for overlap with an unsafe pointer");
1815   return adr_idx == alias_idx;
1816 }
1817 
1818 //------------------------------can_alias--------------------------------------
1819 // True if any values of the given address type are in the given alias category.
1820 bool Compile::can_alias(const TypePtr* adr_type, int alias_idx) {
1821   if (alias_idx == AliasIdxTop)         return false; // the empty category
1822   if (adr_type == NULL)                 return false; // NULL serves as TypePtr::TOP
1823   if (alias_idx == AliasIdxBot)         return true;  // the universal category
1824   if (adr_type->base() == Type::AnyPtr) return true;  // TypePtr::BOTTOM or its twins
1825 
1826   // the only remaining possible overlap is identity
1827   int adr_idx = get_alias_index(adr_type);
1828   assert(adr_idx != AliasIdxBot && adr_idx != AliasIdxTop, "");
1829   return adr_idx == alias_idx;
1830 }
1831 
1832 
1833 
1834 //---------------------------pop_warm_call-------------------------------------
1835 WarmCallInfo* Compile::pop_warm_call() {
1836   WarmCallInfo* wci = _warm_calls;
1837   if (wci != NULL)  _warm_calls = wci->remove_from(wci);
1838   return wci;
1839 }
1840 
1841 //----------------------------Inline_Warm--------------------------------------
1842 int Compile::Inline_Warm() {
1843   // If there is room, try to inline some more warm call sites.
1844   // %%% Do a graph index compaction pass when we think we're out of space?
1845   if (!InlineWarmCalls)  return 0;
1846 
1847   int calls_made_hot = 0;
1848   int room_to_grow   = NodeCountInliningCutoff - unique();
1849   int amount_to_grow = MIN2(room_to_grow, (int)NodeCountInliningStep);
1850   int amount_grown   = 0;
1851   WarmCallInfo* call;
1852   while (amount_to_grow > 0 && (call = pop_warm_call()) != NULL) {
1853     int est_size = (int)call->size();
1854     if (est_size > (room_to_grow - amount_grown)) {
1855       // This one won't fit anyway.  Get rid of it.
1856       call->make_cold();
1857       continue;
1858     }
1859     call->make_hot();
1860     calls_made_hot++;
1861     amount_grown   += est_size;
1862     amount_to_grow -= est_size;
1863   }
1864 
1865   if (calls_made_hot > 0)  set_major_progress();
1866   return calls_made_hot;
1867 }
1868 
1869 
1870 //----------------------------Finish_Warm--------------------------------------
1871 void Compile::Finish_Warm() {
1872   if (!InlineWarmCalls)  return;
1873   if (failing())  return;
1874   if (warm_calls() == NULL)  return;
1875 
1876   // Clean up loose ends, if we are out of space for inlining.
1877   WarmCallInfo* call;
1878   while ((call = pop_warm_call()) != NULL) {
1879     call->make_cold();
1880   }
1881 }
1882 
1883 //---------------------cleanup_loop_predicates-----------------------
1884 // Remove the opaque nodes that protect the predicates so that all unused
1885 // checks and uncommon_traps will be eliminated from the ideal graph
1886 void Compile::cleanup_loop_predicates(PhaseIterGVN &igvn) {
1887   if (predicate_count()==0) return;
1888   for (int i = predicate_count(); i > 0; i--) {
1889     Node * n = predicate_opaque1_node(i-1);
1890     assert(n->Opcode() == Op_Opaque1, "must be");
1891     igvn.replace_node(n, n->in(1));
1892   }
1893   assert(predicate_count()==0, "should be clean!");
1894 }
1895 
1896 // StringOpts and late inlining of string methods
1897 void Compile::inline_string_calls(bool parse_time) {
1898   {
1899     // remove useless nodes to make the usage analysis simpler
1900     ResourceMark rm;
1901     PhaseRemoveUseless pru(initial_gvn(), for_igvn());
1902   }
1903 
1904   {
1905     ResourceMark rm;
1906     print_method(PHASE_BEFORE_STRINGOPTS, 3);
1907     PhaseStringOpts pso(initial_gvn(), for_igvn());
1908     print_method(PHASE_AFTER_STRINGOPTS, 3);
1909   }
1910 
1911   // now inline anything that we skipped the first time around
1912   if (!parse_time) {
1913     _late_inlines_pos = _late_inlines.length();
1914   }
1915 
1916   while (_string_late_inlines.length() > 0) {
1917     CallGenerator* cg = _string_late_inlines.pop();
1918     cg->do_late_inline();
1919     if (failing())  return;
1920   }
1921   _string_late_inlines.trunc_to(0);
1922 }
1923 
1924 // Late inlining of boxing methods
1925 void Compile::inline_boxing_calls(PhaseIterGVN& igvn) {
1926   if (_boxing_late_inlines.length() > 0) {
1927     assert(has_boxed_value(), "inconsistent");
1928 
1929     PhaseGVN* gvn = initial_gvn();
1930     set_inlining_incrementally(true);
1931 
1932     assert( igvn._worklist.size() == 0, "should be done with igvn" );
1933     for_igvn()->clear();
1934     gvn->replace_with(&igvn);
1935 
1936     _late_inlines_pos = _late_inlines.length();
1937 
1938     while (_boxing_late_inlines.length() > 0) {
1939       CallGenerator* cg = _boxing_late_inlines.pop();
1940       cg->do_late_inline();
1941       if (failing())  return;
1942     }
1943     _boxing_late_inlines.trunc_to(0);
1944 
1945     {
1946       ResourceMark rm;
1947       PhaseRemoveUseless pru(gvn, for_igvn());
1948     }
1949 
1950     igvn = PhaseIterGVN(gvn);
1951     igvn.optimize();
1952 
1953     set_inlining_progress(false);
1954     set_inlining_incrementally(false);
1955   }
1956 }
1957 
1958 void Compile::inline_incrementally_one(PhaseIterGVN& igvn) {
1959   assert(IncrementalInline, "incremental inlining should be on");
1960   PhaseGVN* gvn = initial_gvn();
1961 
1962   set_inlining_progress(false);
1963   for_igvn()->clear();
1964   gvn->replace_with(&igvn);
1965 
1966   {
1967     TracePhase tp("incrementalInline_inline", &timers[_t_incrInline_inline]);
1968     int i = 0;
1969     for (; i <_late_inlines.length() && !inlining_progress(); i++) {
1970       CallGenerator* cg = _late_inlines.at(i);
1971       _late_inlines_pos = i+1;
1972       cg->do_late_inline();
1973       if (failing())  return;
1974     }
1975     int j = 0;
1976     for (; i < _late_inlines.length(); i++, j++) {
1977       _late_inlines.at_put(j, _late_inlines.at(i));
1978     }
1979     _late_inlines.trunc_to(j);
1980   }
1981 
1982   {
1983     TracePhase tp("incrementalInline_pru", &timers[_t_incrInline_pru]);
1984     ResourceMark rm;
1985     PhaseRemoveUseless pru(gvn, for_igvn());
1986   }
1987 
1988   {
1989     TracePhase tp("incrementalInline_igvn", &timers[_t_incrInline_igvn]);
1990     igvn = PhaseIterGVN(gvn);
1991   }
1992 }
1993 
1994 // Perform incremental inlining until bound on number of live nodes is reached
1995 void Compile::inline_incrementally(PhaseIterGVN& igvn) {
1996   TracePhase tp("incrementalInline", &timers[_t_incrInline]);
1997 
1998   PhaseGVN* gvn = initial_gvn();
1999 
2000   set_inlining_incrementally(true);
2001   set_inlining_progress(true);
2002   uint low_live_nodes = 0;
2003 
2004   while(inlining_progress() && _late_inlines.length() > 0) {
2005 
2006     if (live_nodes() > (uint)LiveNodeCountInliningCutoff) {
2007       if (low_live_nodes < (uint)LiveNodeCountInliningCutoff * 8 / 10) {
2008         TracePhase tp("incrementalInline_ideal", &timers[_t_incrInline_ideal]);
2009         // PhaseIdealLoop is expensive so we only try it once we are
2010         // out of live nodes and we only try it again if the previous
2011         // helped got the number of nodes down significantly
2012         PhaseIdealLoop ideal_loop( igvn, false, true );
2013         if (failing())  return;
2014         low_live_nodes = live_nodes();
2015         _major_progress = true;
2016       }
2017 
2018       if (live_nodes() > (uint)LiveNodeCountInliningCutoff) {
2019         break;
2020       }
2021     }
2022 
2023     inline_incrementally_one(igvn);
2024 
2025     if (failing())  return;
2026 
2027     {
2028       TracePhase tp("incrementalInline_igvn", &timers[_t_incrInline_igvn]);
2029       igvn.optimize();
2030     }
2031 
2032     if (failing())  return;
2033   }
2034 
2035   assert( igvn._worklist.size() == 0, "should be done with igvn" );
2036 
2037   if (_string_late_inlines.length() > 0) {
2038     assert(has_stringbuilder(), "inconsistent");
2039     for_igvn()->clear();
2040     initial_gvn()->replace_with(&igvn);
2041 
2042     inline_string_calls(false);
2043 
2044     if (failing())  return;
2045 
2046     {
2047       TracePhase tp("incrementalInline_pru", &timers[_t_incrInline_pru]);
2048       ResourceMark rm;
2049       PhaseRemoveUseless pru(initial_gvn(), for_igvn());
2050     }
2051 
2052     {
2053       TracePhase tp("incrementalInline_igvn", &timers[_t_incrInline_igvn]);
2054       igvn = PhaseIterGVN(gvn);
2055       igvn.optimize();
2056     }
2057   }
2058 
2059   set_inlining_incrementally(false);
2060 }
2061 
2062 
2063 //------------------------------Optimize---------------------------------------
2064 // Given a graph, optimize it.
2065 void Compile::Optimize() {
2066   TracePhase tp("optimizer", &timers[_t_optimizer]);
2067 
2068 #ifndef PRODUCT
2069   if (env()->break_at_compile()) {
2070     BREAKPOINT;
2071   }
2072 
2073 #endif
2074 
2075   ResourceMark rm;
2076   int          loop_opts_cnt;
2077 
2078   print_inlining_reinit();
2079 
2080   NOT_PRODUCT( verify_graph_edges(); )
2081 
2082   print_method(PHASE_AFTER_PARSING);
2083 
2084  {
2085   // Iterative Global Value Numbering, including ideal transforms
2086   // Initialize IterGVN with types and values from parse-time GVN
2087   PhaseIterGVN igvn(initial_gvn());
2088 #ifdef ASSERT
2089   _modified_nodes = new (comp_arena()) Unique_Node_List(comp_arena());
2090 #endif
2091   {
2092     TracePhase tp("iterGVN", &timers[_t_iterGVN]);
2093     igvn.optimize();
2094   }
2095 
2096   print_method(PHASE_ITER_GVN1, 2);
2097 
2098   if (failing())  return;
2099 
2100   inline_incrementally(igvn);
2101 
2102   print_method(PHASE_INCREMENTAL_INLINE, 2);
2103 
2104   if (failing())  return;
2105 
2106   if (eliminate_boxing()) {
2107     // Inline valueOf() methods now.
2108     inline_boxing_calls(igvn);
2109 
2110     if (AlwaysIncrementalInline) {
2111       inline_incrementally(igvn);
2112     }
2113 
2114     print_method(PHASE_INCREMENTAL_BOXING_INLINE, 2);
2115 
2116     if (failing())  return;
2117   }
2118 
2119   // Remove the speculative part of types and clean up the graph from
2120   // the extra CastPP nodes whose only purpose is to carry them. Do
2121   // that early so that optimizations are not disrupted by the extra
2122   // CastPP nodes.
2123   remove_speculative_types(igvn);
2124 
2125   // No more new expensive nodes will be added to the list from here
2126   // so keep only the actual candidates for optimizations.
2127   cleanup_expensive_nodes(igvn);
2128 
2129   // Perform escape analysis
2130   if (_do_escape_analysis && ConnectionGraph::has_candidates(this)) {
2131     if (has_loops()) {
2132       // Cleanup graph (remove dead nodes).
2133       TracePhase tp("idealLoop", &timers[_t_idealLoop]);
2134       PhaseIdealLoop ideal_loop( igvn, false, true );
2135       if (major_progress()) print_method(PHASE_PHASEIDEAL_BEFORE_EA, 2);
2136       if (failing())  return;
2137     }
2138     ConnectionGraph::do_analysis(this, &igvn);
2139 
2140     if (failing())  return;
2141 
2142     // Optimize out fields loads from scalar replaceable allocations.
2143     igvn.optimize();
2144     print_method(PHASE_ITER_GVN_AFTER_EA, 2);
2145 
2146     if (failing())  return;
2147 
2148     if (congraph() != NULL && macro_count() > 0) {
2149       TracePhase tp("macroEliminate", &timers[_t_macroEliminate]);
2150       PhaseMacroExpand mexp(igvn);
2151       mexp.eliminate_macro_nodes();
2152       igvn.set_delay_transform(false);
2153 
2154       igvn.optimize();
2155       print_method(PHASE_ITER_GVN_AFTER_ELIMINATION, 2);
2156 
2157       if (failing())  return;
2158     }
2159   }
2160 
2161   // Loop transforms on the ideal graph.  Range Check Elimination,
2162   // peeling, unrolling, etc.
2163 
2164   // Set loop opts counter
2165   loop_opts_cnt = num_loop_opts();
2166   if((loop_opts_cnt > 0) && (has_loops() || has_split_ifs())) {
2167     {
2168       TracePhase tp("idealLoop", &timers[_t_idealLoop]);
2169       PhaseIdealLoop ideal_loop( igvn, true );
2170       loop_opts_cnt--;
2171       if (major_progress()) print_method(PHASE_PHASEIDEALLOOP1, 2);
2172       if (failing())  return;
2173     }
2174     // Loop opts pass if partial peeling occurred in previous pass
2175     if(PartialPeelLoop && major_progress() && (loop_opts_cnt > 0)) {
2176       TracePhase tp("idealLoop", &timers[_t_idealLoop]);
2177       PhaseIdealLoop ideal_loop( igvn, false );
2178       loop_opts_cnt--;
2179       if (major_progress()) print_method(PHASE_PHASEIDEALLOOP2, 2);
2180       if (failing())  return;
2181     }
2182     // Loop opts pass for loop-unrolling before CCP
2183     if(major_progress() && (loop_opts_cnt > 0)) {
2184       TracePhase tp("idealLoop", &timers[_t_idealLoop]);
2185       PhaseIdealLoop ideal_loop( igvn, false );
2186       loop_opts_cnt--;
2187       if (major_progress()) print_method(PHASE_PHASEIDEALLOOP3, 2);
2188     }
2189     if (!failing()) {
2190       // Verify that last round of loop opts produced a valid graph
2191       TracePhase tp("idealLoopVerify", &timers[_t_idealLoopVerify]);
2192       PhaseIdealLoop::verify(igvn);
2193     }
2194   }
2195   if (failing())  return;
2196 
2197   // Conditional Constant Propagation;
2198   PhaseCCP ccp( &igvn );
2199   assert( true, "Break here to ccp.dump_nodes_and_types(_root,999,1)");
2200   {
2201     TracePhase tp("ccp", &timers[_t_ccp]);
2202     ccp.do_transform();
2203   }
2204   print_method(PHASE_CPP1, 2);
2205 
2206   assert( true, "Break here to ccp.dump_old2new_map()");
2207 
2208   // Iterative Global Value Numbering, including ideal transforms
2209   {
2210     TracePhase tp("iterGVN2", &timers[_t_iterGVN2]);
2211     igvn = ccp;
2212     igvn.optimize();
2213   }
2214 
2215   print_method(PHASE_ITER_GVN2, 2);
2216 
2217   if (failing())  return;
2218 
2219   // Loop transforms on the ideal graph.  Range Check Elimination,
2220   // peeling, unrolling, etc.
2221   if(loop_opts_cnt > 0) {
2222     debug_only( int cnt = 0; );
2223     while(major_progress() && (loop_opts_cnt > 0)) {
2224       TracePhase tp("idealLoop", &timers[_t_idealLoop]);
2225       assert( cnt++ < 40, "infinite cycle in loop optimization" );
2226       PhaseIdealLoop ideal_loop( igvn, true);
2227       loop_opts_cnt--;
2228       if (major_progress()) print_method(PHASE_PHASEIDEALLOOP_ITERATIONS, 2);
2229       if (failing())  return;
2230     }
2231   }
2232 
2233   {
2234     // Verify that all previous optimizations produced a valid graph
2235     // at least to this point, even if no loop optimizations were done.
2236     TracePhase tp("idealLoopVerify", &timers[_t_idealLoopVerify]);
2237     PhaseIdealLoop::verify(igvn);
2238   }
2239 
2240   {
2241     TracePhase tp("macroExpand", &timers[_t_macroExpand]);
2242     PhaseMacroExpand  mex(igvn);
2243     if (mex.expand_macro_nodes()) {
2244       assert(failing(), "must bail out w/ explicit message");
2245       return;
2246     }
2247   }
2248 
2249   DEBUG_ONLY( _modified_nodes = NULL; )
2250  } // (End scope of igvn; run destructor if necessary for asserts.)
2251 
2252   process_print_inlining();
2253   // A method with only infinite loops has no edges entering loops from root
2254   {
2255     TracePhase tp("graphReshape", &timers[_t_graphReshaping]);
2256     if (final_graph_reshaping()) {
2257       assert(failing(), "must bail out w/ explicit message");
2258       return;
2259     }
2260   }
2261 
2262   print_method(PHASE_OPTIMIZE_FINISHED, 2);
2263 }
2264 
2265 
2266 //------------------------------Code_Gen---------------------------------------
2267 // Given a graph, generate code for it
2268 void Compile::Code_Gen() {
2269   if (failing()) {
2270     return;
2271   }
2272 
2273   // Perform instruction selection.  You might think we could reclaim Matcher
2274   // memory PDQ, but actually the Matcher is used in generating spill code.
2275   // Internals of the Matcher (including some VectorSets) must remain live
2276   // for awhile - thus I cannot reclaim Matcher memory lest a VectorSet usage
2277   // set a bit in reclaimed memory.
2278 
2279   // In debug mode can dump m._nodes.dump() for mapping of ideal to machine
2280   // nodes.  Mapping is only valid at the root of each matched subtree.
2281   NOT_PRODUCT( verify_graph_edges(); )
2282 
2283   Matcher matcher;
2284   _matcher = &matcher;
2285   {
2286     TracePhase tp("matcher", &timers[_t_matcher]);
2287     matcher.match();
2288   }
2289   // In debug mode can dump m._nodes.dump() for mapping of ideal to machine
2290   // nodes.  Mapping is only valid at the root of each matched subtree.
2291   NOT_PRODUCT( verify_graph_edges(); )
2292 
2293   // If you have too many nodes, or if matching has failed, bail out
2294   check_node_count(0, "out of nodes matching instructions");
2295   if (failing()) {
2296     return;
2297   }
2298 
2299   // Build a proper-looking CFG
2300   PhaseCFG cfg(node_arena(), root(), matcher);
2301   _cfg = &cfg;
2302   {
2303     TracePhase tp("scheduler", &timers[_t_scheduler]);
2304     bool success = cfg.do_global_code_motion();
2305     if (!success) {
2306       return;
2307     }
2308 
2309     print_method(PHASE_GLOBAL_CODE_MOTION, 2);
2310     NOT_PRODUCT( verify_graph_edges(); )
2311     debug_only( cfg.verify(); )
2312   }
2313 
2314   PhaseChaitin regalloc(unique(), cfg, matcher);
2315   _regalloc = &regalloc;
2316   {
2317     TracePhase tp("regalloc", &timers[_t_registerAllocation]);
2318     // Perform register allocation.  After Chaitin, use-def chains are
2319     // no longer accurate (at spill code) and so must be ignored.
2320     // Node->LRG->reg mappings are still accurate.
2321     _regalloc->Register_Allocate();
2322 
2323     // Bail out if the allocator builds too many nodes
2324     if (failing()) {
2325       return;
2326     }
2327   }
2328 
2329   // Prior to register allocation we kept empty basic blocks in case the
2330   // the allocator needed a place to spill.  After register allocation we
2331   // are not adding any new instructions.  If any basic block is empty, we
2332   // can now safely remove it.
2333   {
2334     TracePhase tp("blockOrdering", &timers[_t_blockOrdering]);
2335     cfg.remove_empty_blocks();
2336     if (do_freq_based_layout()) {
2337       PhaseBlockLayout layout(cfg);
2338     } else {
2339       cfg.set_loop_alignment();
2340     }
2341     cfg.fixup_flow();
2342   }
2343 
2344   // Apply peephole optimizations
2345   if( OptoPeephole ) {
2346     TracePhase tp("peephole", &timers[_t_peephole]);
2347     PhasePeephole peep( _regalloc, cfg);
2348     peep.do_transform();
2349   }
2350 
2351   // Do late expand if CPU requires this.
2352   if (Matcher::require_postalloc_expand) {
2353     TracePhase tp("postalloc_expand", &timers[_t_postalloc_expand]);
2354     cfg.postalloc_expand(_regalloc);
2355   }
2356 
2357   // Convert Nodes to instruction bits in a buffer
2358   {
2359     TraceTime tp("output", &timers[_t_output], CITime);
2360     Output();
2361   }
2362 
2363   print_method(PHASE_FINAL_CODE);
2364 
2365   // He's dead, Jim.
2366   _cfg     = (PhaseCFG*)0xdeadbeef;
2367   _regalloc = (PhaseChaitin*)0xdeadbeef;
2368 }
2369 
2370 
2371 //------------------------------dump_asm---------------------------------------
2372 // Dump formatted assembly
2373 #ifndef PRODUCT
2374 void Compile::dump_asm(int *pcs, uint pc_limit) {
2375   bool cut_short = false;
2376   tty->print_cr("#");
2377   tty->print("#  ");  _tf->dump();  tty->cr();
2378   tty->print_cr("#");
2379 
2380   // For all blocks
2381   int pc = 0x0;                 // Program counter
2382   char starts_bundle = ' ';
2383   _regalloc->dump_frame();
2384 
2385   Node *n = NULL;
2386   for (uint i = 0; i < _cfg->number_of_blocks(); i++) {
2387     if (VMThread::should_terminate()) {
2388       cut_short = true;
2389       break;
2390     }
2391     Block* block = _cfg->get_block(i);
2392     if (block->is_connector() && !Verbose) {
2393       continue;
2394     }
2395     n = block->head();
2396     if (pcs && n->_idx < pc_limit) {
2397       tty->print("%3.3x   ", pcs[n->_idx]);
2398     } else {
2399       tty->print("      ");
2400     }
2401     block->dump_head(_cfg);
2402     if (block->is_connector()) {
2403       tty->print_cr("        # Empty connector block");
2404     } else if (block->num_preds() == 2 && block->pred(1)->is_CatchProj() && block->pred(1)->as_CatchProj()->_con == CatchProjNode::fall_through_index) {
2405       tty->print_cr("        # Block is sole successor of call");
2406     }
2407 
2408     // For all instructions
2409     Node *delay = NULL;
2410     for (uint j = 0; j < block->number_of_nodes(); j++) {
2411       if (VMThread::should_terminate()) {
2412         cut_short = true;
2413         break;
2414       }
2415       n = block->get_node(j);
2416       if (valid_bundle_info(n)) {
2417         Bundle* bundle = node_bundling(n);
2418         if (bundle->used_in_unconditional_delay()) {
2419           delay = n;
2420           continue;
2421         }
2422         if (bundle->starts_bundle()) {
2423           starts_bundle = '+';
2424         }
2425       }
2426 
2427       if (WizardMode) {
2428         n->dump();
2429       }
2430 
2431       if( !n->is_Region() &&    // Dont print in the Assembly
2432           !n->is_Phi() &&       // a few noisely useless nodes
2433           !n->is_Proj() &&
2434           !n->is_MachTemp() &&
2435           !n->is_SafePointScalarObject() &&
2436           !n->is_Catch() &&     // Would be nice to print exception table targets
2437           !n->is_MergeMem() &&  // Not very interesting
2438           !n->is_top() &&       // Debug info table constants
2439           !(n->is_Con() && !n->is_Mach())// Debug info table constants
2440           ) {
2441         if (pcs && n->_idx < pc_limit)
2442           tty->print("%3.3x", pcs[n->_idx]);
2443         else
2444           tty->print("   ");
2445         tty->print(" %c ", starts_bundle);
2446         starts_bundle = ' ';
2447         tty->print("\t");
2448         n->format(_regalloc, tty);
2449         tty->cr();
2450       }
2451 
2452       // If we have an instruction with a delay slot, and have seen a delay,
2453       // then back up and print it
2454       if (valid_bundle_info(n) && node_bundling(n)->use_unconditional_delay()) {
2455         assert(delay != NULL, "no unconditional delay instruction");
2456         if (WizardMode) delay->dump();
2457 
2458         if (node_bundling(delay)->starts_bundle())
2459           starts_bundle = '+';
2460         if (pcs && n->_idx < pc_limit)
2461           tty->print("%3.3x", pcs[n->_idx]);
2462         else
2463           tty->print("   ");
2464         tty->print(" %c ", starts_bundle);
2465         starts_bundle = ' ';
2466         tty->print("\t");
2467         delay->format(_regalloc, tty);
2468         tty->cr();
2469         delay = NULL;
2470       }
2471 
2472       // Dump the exception table as well
2473       if( n->is_Catch() && (Verbose || WizardMode) ) {
2474         // Print the exception table for this offset
2475         _handler_table.print_subtable_for(pc);
2476       }
2477     }
2478 
2479     if (pcs && n->_idx < pc_limit)
2480       tty->print_cr("%3.3x", pcs[n->_idx]);
2481     else
2482       tty->cr();
2483 
2484     assert(cut_short || delay == NULL, "no unconditional delay branch");
2485 
2486   } // End of per-block dump
2487   tty->cr();
2488 
2489   if (cut_short)  tty->print_cr("*** disassembly is cut short ***");
2490 }
2491 #endif
2492 
2493 //------------------------------Final_Reshape_Counts---------------------------
2494 // This class defines counters to help identify when a method
2495 // may/must be executed using hardware with only 24-bit precision.
2496 struct Final_Reshape_Counts : public StackObj {
2497   int  _call_count;             // count non-inlined 'common' calls
2498   int  _float_count;            // count float ops requiring 24-bit precision
2499   int  _double_count;           // count double ops requiring more precision
2500   int  _java_call_count;        // count non-inlined 'java' calls
2501   int  _inner_loop_count;       // count loops which need alignment
2502   VectorSet _visited;           // Visitation flags
2503   Node_List _tests;             // Set of IfNodes & PCTableNodes
2504 
2505   Final_Reshape_Counts() :
2506     _call_count(0), _float_count(0), _double_count(0),
2507     _java_call_count(0), _inner_loop_count(0),
2508     _visited( Thread::current()->resource_area() ) { }
2509 
2510   void inc_call_count  () { _call_count  ++; }
2511   void inc_float_count () { _float_count ++; }
2512   void inc_double_count() { _double_count++; }
2513   void inc_java_call_count() { _java_call_count++; }
2514   void inc_inner_loop_count() { _inner_loop_count++; }
2515 
2516   int  get_call_count  () const { return _call_count  ; }
2517   int  get_float_count () const { return _float_count ; }
2518   int  get_double_count() const { return _double_count; }
2519   int  get_java_call_count() const { return _java_call_count; }
2520   int  get_inner_loop_count() const { return _inner_loop_count; }
2521 };
2522 
2523 #ifdef ASSERT
2524 static bool oop_offset_is_sane(const TypeInstPtr* tp) {
2525   ciInstanceKlass *k = tp->klass()->as_instance_klass();
2526   // Make sure the offset goes inside the instance layout.
2527   return k->contains_field_offset(tp->offset());
2528   // Note that OffsetBot and OffsetTop are very negative.
2529 }
2530 #endif
2531 
2532 // Eliminate trivially redundant StoreCMs and accumulate their
2533 // precedence edges.
2534 void Compile::eliminate_redundant_card_marks(Node* n) {
2535   assert(n->Opcode() == Op_StoreCM, "expected StoreCM");
2536   if (n->in(MemNode::Address)->outcnt() > 1) {
2537     // There are multiple users of the same address so it might be
2538     // possible to eliminate some of the StoreCMs
2539     Node* mem = n->in(MemNode::Memory);
2540     Node* adr = n->in(MemNode::Address);
2541     Node* val = n->in(MemNode::ValueIn);
2542     Node* prev = n;
2543     bool done = false;
2544     // Walk the chain of StoreCMs eliminating ones that match.  As
2545     // long as it's a chain of single users then the optimization is
2546     // safe.  Eliminating partially redundant StoreCMs would require
2547     // cloning copies down the other paths.
2548     while (mem->Opcode() == Op_StoreCM && mem->outcnt() == 1 && !done) {
2549       if (adr == mem->in(MemNode::Address) &&
2550           val == mem->in(MemNode::ValueIn)) {
2551         // redundant StoreCM
2552         if (mem->req() > MemNode::OopStore) {
2553           // Hasn't been processed by this code yet.
2554           n->add_prec(mem->in(MemNode::OopStore));
2555         } else {
2556           // Already converted to precedence edge
2557           for (uint i = mem->req(); i < mem->len(); i++) {
2558             // Accumulate any precedence edges
2559             if (mem->in(i) != NULL) {
2560               n->add_prec(mem->in(i));
2561             }
2562           }
2563           // Everything above this point has been processed.
2564           done = true;
2565         }
2566         // Eliminate the previous StoreCM
2567         prev->set_req(MemNode::Memory, mem->in(MemNode::Memory));
2568         assert(mem->outcnt() == 0, "should be dead");
2569         mem->disconnect_inputs(NULL, this);
2570       } else {
2571         prev = mem;
2572       }
2573       mem = prev->in(MemNode::Memory);
2574     }
2575   }
2576 }
2577 
2578 //------------------------------final_graph_reshaping_impl----------------------
2579 // Implement items 1-5 from final_graph_reshaping below.
2580 void Compile::final_graph_reshaping_impl( Node *n, Final_Reshape_Counts &frc) {
2581 
2582   if ( n->outcnt() == 0 ) return; // dead node
2583   uint nop = n->Opcode();
2584 
2585   // Check for 2-input instruction with "last use" on right input.
2586   // Swap to left input.  Implements item (2).
2587   if( n->req() == 3 &&          // two-input instruction
2588       n->in(1)->outcnt() > 1 && // left use is NOT a last use
2589       (!n->in(1)->is_Phi() || n->in(1)->in(2) != n) && // it is not data loop
2590       n->in(2)->outcnt() == 1 &&// right use IS a last use
2591       !n->in(2)->is_Con() ) {   // right use is not a constant
2592     // Check for commutative opcode
2593     switch( nop ) {
2594     case Op_AddI:  case Op_AddF:  case Op_AddD:  case Op_AddL:
2595     case Op_MaxI:  case Op_MinI:
2596     case Op_MulI:  case Op_MulF:  case Op_MulD:  case Op_MulL:
2597     case Op_AndL:  case Op_XorL:  case Op_OrL:
2598     case Op_AndI:  case Op_XorI:  case Op_OrI: {
2599       // Move "last use" input to left by swapping inputs
2600       n->swap_edges(1, 2);
2601       break;
2602     }
2603     default:
2604       break;
2605     }
2606   }
2607 
2608 #ifdef ASSERT
2609   if( n->is_Mem() ) {
2610     int alias_idx = get_alias_index(n->as_Mem()->adr_type());
2611     assert( n->in(0) != NULL || alias_idx != Compile::AliasIdxRaw ||
2612             // oop will be recorded in oop map if load crosses safepoint
2613             n->is_Load() && (n->as_Load()->bottom_type()->isa_oopptr() ||
2614                              LoadNode::is_immutable_value(n->in(MemNode::Address))),
2615             "raw memory operations should have control edge");
2616   }
2617 #endif
2618   // Count FPU ops and common calls, implements item (3)
2619   switch( nop ) {
2620   // Count all float operations that may use FPU
2621   case Op_AddF:
2622   case Op_SubF:
2623   case Op_MulF:
2624   case Op_DivF:
2625   case Op_NegF:
2626   case Op_ModF:
2627   case Op_ConvI2F:
2628   case Op_ConF:
2629   case Op_CmpF:
2630   case Op_CmpF3:
2631   // case Op_ConvL2F: // longs are split into 32-bit halves
2632     frc.inc_float_count();
2633     break;
2634 
2635   case Op_ConvF2D:
2636   case Op_ConvD2F:
2637     frc.inc_float_count();
2638     frc.inc_double_count();
2639     break;
2640 
2641   // Count all double operations that may use FPU
2642   case Op_AddD:
2643   case Op_SubD:
2644   case Op_MulD:
2645   case Op_DivD:
2646   case Op_NegD:
2647   case Op_ModD:
2648   case Op_ConvI2D:
2649   case Op_ConvD2I:
2650   // case Op_ConvL2D: // handled by leaf call
2651   // case Op_ConvD2L: // handled by leaf call
2652   case Op_ConD:
2653   case Op_CmpD:
2654   case Op_CmpD3:
2655     frc.inc_double_count();
2656     break;
2657   case Op_Opaque1:              // Remove Opaque Nodes before matching
2658   case Op_Opaque2:              // Remove Opaque Nodes before matching
2659   case Op_Opaque3:
2660     n->subsume_by(n->in(1), this);
2661     break;
2662   case Op_CallStaticJava:
2663   case Op_CallJava:
2664   case Op_CallDynamicJava:
2665     frc.inc_java_call_count(); // Count java call site;
2666   case Op_CallRuntime:
2667   case Op_CallLeaf:
2668   case Op_CallLeafNoFP: {
2669     assert( n->is_Call(), "" );
2670     CallNode *call = n->as_Call();
2671     // Count call sites where the FP mode bit would have to be flipped.
2672     // Do not count uncommon runtime calls:
2673     // uncommon_trap, _complete_monitor_locking, _complete_monitor_unlocking,
2674     // _new_Java, _new_typeArray, _new_objArray, _rethrow_Java, ...
2675     if( !call->is_CallStaticJava() || !call->as_CallStaticJava()->_name ) {
2676       frc.inc_call_count();   // Count the call site
2677     } else {                  // See if uncommon argument is shared
2678       Node *n = call->in(TypeFunc::Parms);
2679       int nop = n->Opcode();
2680       // Clone shared simple arguments to uncommon calls, item (1).
2681       if( n->outcnt() > 1 &&
2682           !n->is_Proj() &&
2683           nop != Op_CreateEx &&
2684           nop != Op_CheckCastPP &&
2685           nop != Op_DecodeN &&
2686           nop != Op_DecodeNKlass &&
2687           !n->is_Mem() ) {
2688         Node *x = n->clone();
2689         call->set_req( TypeFunc::Parms, x );
2690       }
2691     }
2692     break;
2693   }
2694 
2695   case Op_StoreD:
2696   case Op_LoadD:
2697   case Op_LoadD_unaligned:
2698     frc.inc_double_count();
2699     goto handle_mem;
2700   case Op_StoreF:
2701   case Op_LoadF:
2702     frc.inc_float_count();
2703     goto handle_mem;
2704 
2705   case Op_StoreCM:
2706     {
2707       // Convert OopStore dependence into precedence edge
2708       Node* prec = n->in(MemNode::OopStore);
2709       n->del_req(MemNode::OopStore);
2710       n->add_prec(prec);
2711       eliminate_redundant_card_marks(n);
2712     }
2713 
2714     // fall through
2715 
2716   case Op_StoreB:
2717   case Op_StoreC:
2718   case Op_StorePConditional:
2719   case Op_StoreI:
2720   case Op_StoreL:
2721   case Op_StoreIConditional:
2722   case Op_StoreLConditional:
2723   case Op_CompareAndSwapI:
2724   case Op_CompareAndSwapL:
2725   case Op_CompareAndSwapP:
2726   case Op_CompareAndSwapN:
2727   case Op_GetAndAddI:
2728   case Op_GetAndAddL:
2729   case Op_GetAndSetI:
2730   case Op_GetAndSetL:
2731   case Op_GetAndSetP:
2732   case Op_GetAndSetN:
2733   case Op_StoreP:
2734   case Op_StoreN:
2735   case Op_StoreNKlass:
2736   case Op_LoadB:
2737   case Op_LoadUB:
2738   case Op_LoadUS:
2739   case Op_LoadI:
2740   case Op_LoadKlass:
2741   case Op_LoadNKlass:
2742   case Op_LoadL:
2743   case Op_LoadL_unaligned:
2744   case Op_LoadPLocked:
2745   case Op_LoadP:
2746   case Op_LoadN:
2747   case Op_LoadRange:
2748   case Op_LoadS: {
2749   handle_mem:
2750 #ifdef ASSERT
2751     if( VerifyOptoOopOffsets ) {
2752       assert( n->is_Mem(), "" );
2753       MemNode *mem  = (MemNode*)n;
2754       // Check to see if address types have grounded out somehow.
2755       const TypeInstPtr *tp = mem->in(MemNode::Address)->bottom_type()->isa_instptr();
2756       assert( !tp || oop_offset_is_sane(tp), "" );
2757     }
2758 #endif
2759     break;
2760   }
2761 
2762   case Op_AddP: {               // Assert sane base pointers
2763     Node *addp = n->in(AddPNode::Address);
2764     assert( !addp->is_AddP() ||
2765             addp->in(AddPNode::Base)->is_top() || // Top OK for allocation
2766             addp->in(AddPNode::Base) == n->in(AddPNode::Base),
2767             "Base pointers must match" );
2768 #ifdef _LP64
2769     if ((UseCompressedOops || UseCompressedClassPointers) &&
2770         addp->Opcode() == Op_ConP &&
2771         addp == n->in(AddPNode::Base) &&
2772         n->in(AddPNode::Offset)->is_Con()) {
2773       // Use addressing with narrow klass to load with offset on x86.
2774       // On sparc loading 32-bits constant and decoding it have less
2775       // instructions (4) then load 64-bits constant (7).
2776       // Do this transformation here since IGVN will convert ConN back to ConP.
2777       const Type* t = addp->bottom_type();
2778       if (t->isa_oopptr() || t->isa_klassptr()) {
2779         Node* nn = NULL;
2780 
2781         int op = t->isa_oopptr() ? Op_ConN : Op_ConNKlass;
2782 
2783         // Look for existing ConN node of the same exact type.
2784         Node* r  = root();
2785         uint cnt = r->outcnt();
2786         for (uint i = 0; i < cnt; i++) {
2787           Node* m = r->raw_out(i);
2788           if (m!= NULL && m->Opcode() == op &&
2789               m->bottom_type()->make_ptr() == t) {
2790             nn = m;
2791             break;
2792           }
2793         }
2794         if (nn != NULL) {
2795           // Decode a narrow oop to match address
2796           // [R12 + narrow_oop_reg<<3 + offset]
2797           if (t->isa_oopptr()) {
2798             nn = new DecodeNNode(nn, t);
2799           } else {
2800             nn = new DecodeNKlassNode(nn, t);
2801           }
2802           n->set_req(AddPNode::Base, nn);
2803           n->set_req(AddPNode::Address, nn);
2804           if (addp->outcnt() == 0) {
2805             addp->disconnect_inputs(NULL, this);
2806           }
2807         }
2808       }
2809     }
2810 #endif
2811     break;
2812   }
2813 
2814 #ifdef _LP64
2815   case Op_CastPP:
2816     if (n->in(1)->is_DecodeN() && Matcher::gen_narrow_oop_implicit_null_checks()) {
2817       Node* in1 = n->in(1);
2818       const Type* t = n->bottom_type();
2819       Node* new_in1 = in1->clone();
2820       new_in1->as_DecodeN()->set_type(t);
2821 
2822       if (!Matcher::narrow_oop_use_complex_address()) {
2823         //
2824         // x86, ARM and friends can handle 2 adds in addressing mode
2825         // and Matcher can fold a DecodeN node into address by using
2826         // a narrow oop directly and do implicit NULL check in address:
2827         //
2828         // [R12 + narrow_oop_reg<<3 + offset]
2829         // NullCheck narrow_oop_reg
2830         //
2831         // On other platforms (Sparc) we have to keep new DecodeN node and
2832         // use it to do implicit NULL check in address:
2833         //
2834         // decode_not_null narrow_oop_reg, base_reg
2835         // [base_reg + offset]
2836         // NullCheck base_reg
2837         //
2838         // Pin the new DecodeN node to non-null path on these platform (Sparc)
2839         // to keep the information to which NULL check the new DecodeN node
2840         // corresponds to use it as value in implicit_null_check().
2841         //
2842         new_in1->set_req(0, n->in(0));
2843       }
2844 
2845       n->subsume_by(new_in1, this);
2846       if (in1->outcnt() == 0) {
2847         in1->disconnect_inputs(NULL, this);
2848       }
2849     }
2850     break;
2851 
2852   case Op_CmpP:
2853     // Do this transformation here to preserve CmpPNode::sub() and
2854     // other TypePtr related Ideal optimizations (for example, ptr nullness).
2855     if (n->in(1)->is_DecodeNarrowPtr() || n->in(2)->is_DecodeNarrowPtr()) {
2856       Node* in1 = n->in(1);
2857       Node* in2 = n->in(2);
2858       if (!in1->is_DecodeNarrowPtr()) {
2859         in2 = in1;
2860         in1 = n->in(2);
2861       }
2862       assert(in1->is_DecodeNarrowPtr(), "sanity");
2863 
2864       Node* new_in2 = NULL;
2865       if (in2->is_DecodeNarrowPtr()) {
2866         assert(in2->Opcode() == in1->Opcode(), "must be same node type");
2867         new_in2 = in2->in(1);
2868       } else if (in2->Opcode() == Op_ConP) {
2869         const Type* t = in2->bottom_type();
2870         if (t == TypePtr::NULL_PTR) {
2871           assert(in1->is_DecodeN(), "compare klass to null?");
2872           // Don't convert CmpP null check into CmpN if compressed
2873           // oops implicit null check is not generated.
2874           // This will allow to generate normal oop implicit null check.
2875           if (Matcher::gen_narrow_oop_implicit_null_checks())
2876             new_in2 = ConNode::make(TypeNarrowOop::NULL_PTR);
2877           //
2878           // This transformation together with CastPP transformation above
2879           // will generated code for implicit NULL checks for compressed oops.
2880           //
2881           // The original code after Optimize()
2882           //
2883           //    LoadN memory, narrow_oop_reg
2884           //    decode narrow_oop_reg, base_reg
2885           //    CmpP base_reg, NULL
2886           //    CastPP base_reg // NotNull
2887           //    Load [base_reg + offset], val_reg
2888           //
2889           // after these transformations will be
2890           //
2891           //    LoadN memory, narrow_oop_reg
2892           //    CmpN narrow_oop_reg, NULL
2893           //    decode_not_null narrow_oop_reg, base_reg
2894           //    Load [base_reg + offset], val_reg
2895           //
2896           // and the uncommon path (== NULL) will use narrow_oop_reg directly
2897           // since narrow oops can be used in debug info now (see the code in
2898           // final_graph_reshaping_walk()).
2899           //
2900           // At the end the code will be matched to
2901           // on x86:
2902           //
2903           //    Load_narrow_oop memory, narrow_oop_reg
2904           //    Load [R12 + narrow_oop_reg<<3 + offset], val_reg
2905           //    NullCheck narrow_oop_reg
2906           //
2907           // and on sparc:
2908           //
2909           //    Load_narrow_oop memory, narrow_oop_reg
2910           //    decode_not_null narrow_oop_reg, base_reg
2911           //    Load [base_reg + offset], val_reg
2912           //    NullCheck base_reg
2913           //
2914         } else if (t->isa_oopptr()) {
2915           new_in2 = ConNode::make(t->make_narrowoop());
2916         } else if (t->isa_klassptr()) {
2917           new_in2 = ConNode::make(t->make_narrowklass());
2918         }
2919       }
2920       if (new_in2 != NULL) {
2921         Node* cmpN = new CmpNNode(in1->in(1), new_in2);
2922         n->subsume_by(cmpN, this);
2923         if (in1->outcnt() == 0) {
2924           in1->disconnect_inputs(NULL, this);
2925         }
2926         if (in2->outcnt() == 0) {
2927           in2->disconnect_inputs(NULL, this);
2928         }
2929       }
2930     }
2931     break;
2932 
2933   case Op_DecodeN:
2934   case Op_DecodeNKlass:
2935     assert(!n->in(1)->is_EncodeNarrowPtr(), "should be optimized out");
2936     // DecodeN could be pinned when it can't be fold into
2937     // an address expression, see the code for Op_CastPP above.
2938     assert(n->in(0) == NULL || (UseCompressedOops && !Matcher::narrow_oop_use_complex_address()), "no control");
2939     break;
2940 
2941   case Op_EncodeP:
2942   case Op_EncodePKlass: {
2943     Node* in1 = n->in(1);
2944     if (in1->is_DecodeNarrowPtr()) {
2945       n->subsume_by(in1->in(1), this);
2946     } else if (in1->Opcode() == Op_ConP) {
2947       const Type* t = in1->bottom_type();
2948       if (t == TypePtr::NULL_PTR) {
2949         assert(t->isa_oopptr(), "null klass?");
2950         n->subsume_by(ConNode::make(TypeNarrowOop::NULL_PTR), this);
2951       } else if (t->isa_oopptr()) {
2952         n->subsume_by(ConNode::make(t->make_narrowoop()), this);
2953       } else if (t->isa_klassptr()) {
2954         n->subsume_by(ConNode::make(t->make_narrowklass()), this);
2955       }
2956     }
2957     if (in1->outcnt() == 0) {
2958       in1->disconnect_inputs(NULL, this);
2959     }
2960     break;
2961   }
2962 
2963   case Op_Proj: {
2964     if (OptimizeStringConcat) {
2965       ProjNode* p = n->as_Proj();
2966       if (p->_is_io_use) {
2967         // Separate projections were used for the exception path which
2968         // are normally removed by a late inline.  If it wasn't inlined
2969         // then they will hang around and should just be replaced with
2970         // the original one.
2971         Node* proj = NULL;
2972         // Replace with just one
2973         for (SimpleDUIterator i(p->in(0)); i.has_next(); i.next()) {
2974           Node *use = i.get();
2975           if (use->is_Proj() && p != use && use->as_Proj()->_con == p->_con) {
2976             proj = use;
2977             break;
2978           }
2979         }
2980         assert(proj != NULL, "must be found");
2981         p->subsume_by(proj, this);
2982       }
2983     }
2984     break;
2985   }
2986 
2987   case Op_Phi:
2988     if (n->as_Phi()->bottom_type()->isa_narrowoop() || n->as_Phi()->bottom_type()->isa_narrowklass()) {
2989       // The EncodeP optimization may create Phi with the same edges
2990       // for all paths. It is not handled well by Register Allocator.
2991       Node* unique_in = n->in(1);
2992       assert(unique_in != NULL, "");
2993       uint cnt = n->req();
2994       for (uint i = 2; i < cnt; i++) {
2995         Node* m = n->in(i);
2996         assert(m != NULL, "");
2997         if (unique_in != m)
2998           unique_in = NULL;
2999       }
3000       if (unique_in != NULL) {
3001         n->subsume_by(unique_in, this);
3002       }
3003     }
3004     break;
3005 
3006 #endif
3007 
3008   case Op_ModI:
3009     if (UseDivMod) {
3010       // Check if a%b and a/b both exist
3011       Node* d = n->find_similar(Op_DivI);
3012       if (d) {
3013         // Replace them with a fused divmod if supported
3014         if (Matcher::has_match_rule(Op_DivModI)) {
3015           DivModINode* divmod = DivModINode::make(n);
3016           d->subsume_by(divmod->div_proj(), this);
3017           n->subsume_by(divmod->mod_proj(), this);
3018         } else {
3019           // replace a%b with a-((a/b)*b)
3020           Node* mult = new MulINode(d, d->in(2));
3021           Node* sub  = new SubINode(d->in(1), mult);
3022           n->subsume_by(sub, this);
3023         }
3024       }
3025     }
3026     break;
3027 
3028   case Op_ModL:
3029     if (UseDivMod) {
3030       // Check if a%b and a/b both exist
3031       Node* d = n->find_similar(Op_DivL);
3032       if (d) {
3033         // Replace them with a fused divmod if supported
3034         if (Matcher::has_match_rule(Op_DivModL)) {
3035           DivModLNode* divmod = DivModLNode::make(n);
3036           d->subsume_by(divmod->div_proj(), this);
3037           n->subsume_by(divmod->mod_proj(), this);
3038         } else {
3039           // replace a%b with a-((a/b)*b)
3040           Node* mult = new MulLNode(d, d->in(2));
3041           Node* sub  = new SubLNode(d->in(1), mult);
3042           n->subsume_by(sub, this);
3043         }
3044       }
3045     }
3046     break;
3047 
3048   case Op_LoadVector:
3049   case Op_StoreVector:
3050     break;
3051 
3052   case Op_PackB:
3053   case Op_PackS:
3054   case Op_PackI:
3055   case Op_PackF:
3056   case Op_PackL:
3057   case Op_PackD:
3058     if (n->req()-1 > 2) {
3059       // Replace many operand PackNodes with a binary tree for matching
3060       PackNode* p = (PackNode*) n;
3061       Node* btp = p->binary_tree_pack(1, n->req());
3062       n->subsume_by(btp, this);
3063     }
3064     break;
3065   case Op_Loop:
3066   case Op_CountedLoop:
3067     if (n->as_Loop()->is_inner_loop()) {
3068       frc.inc_inner_loop_count();
3069     }
3070     break;
3071   case Op_LShiftI:
3072   case Op_RShiftI:
3073   case Op_URShiftI:
3074   case Op_LShiftL:
3075   case Op_RShiftL:
3076   case Op_URShiftL:
3077     if (Matcher::need_masked_shift_count) {
3078       // The cpu's shift instructions don't restrict the count to the
3079       // lower 5/6 bits. We need to do the masking ourselves.
3080       Node* in2 = n->in(2);
3081       juint mask = (n->bottom_type() == TypeInt::INT) ? (BitsPerInt - 1) : (BitsPerLong - 1);
3082       const TypeInt* t = in2->find_int_type();
3083       if (t != NULL && t->is_con()) {
3084         juint shift = t->get_con();
3085         if (shift > mask) { // Unsigned cmp
3086           n->set_req(2, ConNode::make(TypeInt::make(shift & mask)));
3087         }
3088       } else {
3089         if (t == NULL || t->_lo < 0 || t->_hi > (int)mask) {
3090           Node* shift = new AndINode(in2, ConNode::make(TypeInt::make(mask)));
3091           n->set_req(2, shift);
3092         }
3093       }
3094       if (in2->outcnt() == 0) { // Remove dead node
3095         in2->disconnect_inputs(NULL, this);
3096       }
3097     }
3098     break;
3099   case Op_MemBarStoreStore:
3100   case Op_MemBarRelease:
3101     // Break the link with AllocateNode: it is no longer useful and
3102     // confuses register allocation.
3103     if (n->req() > MemBarNode::Precedent) {
3104       n->set_req(MemBarNode::Precedent, top());
3105     }
3106     break;
3107   default:
3108     assert( !n->is_Call(), "" );
3109     assert( !n->is_Mem(), "" );
3110     assert( nop != Op_ProfileBoolean, "should be eliminated during IGVN");
3111     break;
3112   }
3113 
3114   // Collect CFG split points
3115   if (n->is_MultiBranch())
3116     frc._tests.push(n);
3117 }
3118 
3119 //------------------------------final_graph_reshaping_walk---------------------
3120 // Replacing Opaque nodes with their input in final_graph_reshaping_impl(),
3121 // requires that the walk visits a node's inputs before visiting the node.
3122 void Compile::final_graph_reshaping_walk( Node_Stack &nstack, Node *root, Final_Reshape_Counts &frc ) {
3123   ResourceArea *area = Thread::current()->resource_area();
3124   Unique_Node_List sfpt(area);
3125 
3126   frc._visited.set(root->_idx); // first, mark node as visited
3127   uint cnt = root->req();
3128   Node *n = root;
3129   uint  i = 0;
3130   while (true) {
3131     if (i < cnt) {
3132       // Place all non-visited non-null inputs onto stack
3133       Node* m = n->in(i);
3134       ++i;
3135       if (m != NULL && !frc._visited.test_set(m->_idx)) {
3136         if (m->is_SafePoint() && m->as_SafePoint()->jvms() != NULL) {
3137           // compute worst case interpreter size in case of a deoptimization
3138           update_interpreter_frame_size(m->as_SafePoint()->jvms()->interpreter_frame_size());
3139 
3140           sfpt.push(m);
3141         }
3142         cnt = m->req();
3143         nstack.push(n, i); // put on stack parent and next input's index
3144         n = m;
3145         i = 0;
3146       }
3147     } else {
3148       // Now do post-visit work
3149       final_graph_reshaping_impl( n, frc );
3150       if (nstack.is_empty())
3151         break;             // finished
3152       n = nstack.node();   // Get node from stack
3153       cnt = n->req();
3154       i = nstack.index();
3155       nstack.pop();        // Shift to the next node on stack
3156     }
3157   }
3158 
3159   // Skip next transformation if compressed oops are not used.
3160   if ((UseCompressedOops && !Matcher::gen_narrow_oop_implicit_null_checks()) ||
3161       (!UseCompressedOops && !UseCompressedClassPointers))
3162     return;
3163 
3164   // Go over safepoints nodes to skip DecodeN/DecodeNKlass nodes for debug edges.
3165   // It could be done for an uncommon traps or any safepoints/calls
3166   // if the DecodeN/DecodeNKlass node is referenced only in a debug info.
3167   while (sfpt.size() > 0) {
3168     n = sfpt.pop();
3169     JVMState *jvms = n->as_SafePoint()->jvms();
3170     assert(jvms != NULL, "sanity");
3171     int start = jvms->debug_start();
3172     int end   = n->req();
3173     bool is_uncommon = (n->is_CallStaticJava() &&
3174                         n->as_CallStaticJava()->uncommon_trap_request() != 0);
3175     for (int j = start; j < end; j++) {
3176       Node* in = n->in(j);
3177       if (in->is_DecodeNarrowPtr()) {
3178         bool safe_to_skip = true;
3179         if (!is_uncommon ) {
3180           // Is it safe to skip?
3181           for (uint i = 0; i < in->outcnt(); i++) {
3182             Node* u = in->raw_out(i);
3183             if (!u->is_SafePoint() ||
3184                  u->is_Call() && u->as_Call()->has_non_debug_use(n)) {
3185               safe_to_skip = false;
3186             }
3187           }
3188         }
3189         if (safe_to_skip) {
3190           n->set_req(j, in->in(1));
3191         }
3192         if (in->outcnt() == 0) {
3193           in->disconnect_inputs(NULL, this);
3194         }
3195       }
3196     }
3197   }
3198 }
3199 
3200 //------------------------------final_graph_reshaping--------------------------
3201 // Final Graph Reshaping.
3202 //
3203 // (1) Clone simple inputs to uncommon calls, so they can be scheduled late
3204 //     and not commoned up and forced early.  Must come after regular
3205 //     optimizations to avoid GVN undoing the cloning.  Clone constant
3206 //     inputs to Loop Phis; these will be split by the allocator anyways.
3207 //     Remove Opaque nodes.
3208 // (2) Move last-uses by commutative operations to the left input to encourage
3209 //     Intel update-in-place two-address operations and better register usage
3210 //     on RISCs.  Must come after regular optimizations to avoid GVN Ideal
3211 //     calls canonicalizing them back.
3212 // (3) Count the number of double-precision FP ops, single-precision FP ops
3213 //     and call sites.  On Intel, we can get correct rounding either by
3214 //     forcing singles to memory (requires extra stores and loads after each
3215 //     FP bytecode) or we can set a rounding mode bit (requires setting and
3216 //     clearing the mode bit around call sites).  The mode bit is only used
3217 //     if the relative frequency of single FP ops to calls is low enough.
3218 //     This is a key transform for SPEC mpeg_audio.
3219 // (4) Detect infinite loops; blobs of code reachable from above but not
3220 //     below.  Several of the Code_Gen algorithms fail on such code shapes,
3221 //     so we simply bail out.  Happens a lot in ZKM.jar, but also happens
3222 //     from time to time in other codes (such as -Xcomp finalizer loops, etc).
3223 //     Detection is by looking for IfNodes where only 1 projection is
3224 //     reachable from below or CatchNodes missing some targets.
3225 // (5) Assert for insane oop offsets in debug mode.
3226 
3227 bool Compile::final_graph_reshaping() {
3228   // an infinite loop may have been eliminated by the optimizer,
3229   // in which case the graph will be empty.
3230   if (root()->req() == 1) {
3231     record_method_not_compilable("trivial infinite loop");
3232     return true;
3233   }
3234 
3235   // Expensive nodes have their control input set to prevent the GVN
3236   // from freely commoning them. There's no GVN beyond this point so
3237   // no need to keep the control input. We want the expensive nodes to
3238   // be freely moved to the least frequent code path by gcm.
3239   assert(OptimizeExpensiveOps || expensive_count() == 0, "optimization off but list non empty?");
3240   for (int i = 0; i < expensive_count(); i++) {
3241     _expensive_nodes->at(i)->set_req(0, NULL);
3242   }
3243 
3244   Final_Reshape_Counts frc;
3245 
3246   // Visit everybody reachable!
3247   // Allocate stack of size C->unique()/2 to avoid frequent realloc
3248   Node_Stack nstack(unique() >> 1);
3249   final_graph_reshaping_walk(nstack, root(), frc);
3250 
3251   // Check for unreachable (from below) code (i.e., infinite loops).
3252   for( uint i = 0; i < frc._tests.size(); i++ ) {
3253     MultiBranchNode *n = frc._tests[i]->as_MultiBranch();
3254     // Get number of CFG targets.
3255     // Note that PCTables include exception targets after calls.
3256     uint required_outcnt = n->required_outcnt();
3257     if (n->outcnt() != required_outcnt) {
3258       // Check for a few special cases.  Rethrow Nodes never take the
3259       // 'fall-thru' path, so expected kids is 1 less.
3260       if (n->is_PCTable() && n->in(0) && n->in(0)->in(0)) {
3261         if (n->in(0)->in(0)->is_Call()) {
3262           CallNode *call = n->in(0)->in(0)->as_Call();
3263           if (call->entry_point() == OptoRuntime::rethrow_stub()) {
3264             required_outcnt--;      // Rethrow always has 1 less kid
3265           } else if (call->req() > TypeFunc::Parms &&
3266                      call->is_CallDynamicJava()) {
3267             // Check for null receiver. In such case, the optimizer has
3268             // detected that the virtual call will always result in a null
3269             // pointer exception. The fall-through projection of this CatchNode
3270             // will not be populated.
3271             Node *arg0 = call->in(TypeFunc::Parms);
3272             if (arg0->is_Type() &&
3273                 arg0->as_Type()->type()->higher_equal(TypePtr::NULL_PTR)) {
3274               required_outcnt--;
3275             }
3276           } else if (call->entry_point() == OptoRuntime::new_array_Java() &&
3277                      call->req() > TypeFunc::Parms+1 &&
3278                      call->is_CallStaticJava()) {
3279             // Check for negative array length. In such case, the optimizer has
3280             // detected that the allocation attempt will always result in an
3281             // exception. There is no fall-through projection of this CatchNode .
3282             Node *arg1 = call->in(TypeFunc::Parms+1);
3283             if (arg1->is_Type() &&
3284                 arg1->as_Type()->type()->join(TypeInt::POS)->empty()) {
3285               required_outcnt--;
3286             }
3287           }
3288         }
3289       }
3290       // Recheck with a better notion of 'required_outcnt'
3291       if (n->outcnt() != required_outcnt) {
3292         record_method_not_compilable("malformed control flow");
3293         return true;            // Not all targets reachable!
3294       }
3295     }
3296     // Check that I actually visited all kids.  Unreached kids
3297     // must be infinite loops.
3298     for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++)
3299       if (!frc._visited.test(n->fast_out(j)->_idx)) {
3300         record_method_not_compilable("infinite loop");
3301         return true;            // Found unvisited kid; must be unreach
3302       }
3303   }
3304 
3305   // If original bytecodes contained a mixture of floats and doubles
3306   // check if the optimizer has made it homogenous, item (3).
3307   if( Use24BitFPMode && Use24BitFP && UseSSE == 0 &&
3308       frc.get_float_count() > 32 &&
3309       frc.get_double_count() == 0 &&
3310       (10 * frc.get_call_count() < frc.get_float_count()) ) {
3311     set_24_bit_selection_and_mode( false,  true );
3312   }
3313 
3314   set_java_calls(frc.get_java_call_count());
3315   set_inner_loops(frc.get_inner_loop_count());
3316 
3317   // No infinite loops, no reason to bail out.
3318   return false;
3319 }
3320 
3321 //-----------------------------too_many_traps----------------------------------
3322 // Report if there are too many traps at the current method and bci.
3323 // Return true if there was a trap, and/or PerMethodTrapLimit is exceeded.
3324 bool Compile::too_many_traps(ciMethod* method,
3325                              int bci,
3326                              Deoptimization::DeoptReason reason) {
3327   if (method->has_injected_profile()) {
3328     return false;
3329   }
3330   ciMethodData* md = method->method_data();
3331   if (md->is_empty()) {
3332     // Assume the trap has not occurred, or that it occurred only
3333     // because of a transient condition during start-up in the interpreter.
3334     return false;
3335   }
3336   ciMethod* m = Deoptimization::reason_is_speculate(reason) ? this->method() : NULL;
3337   if (md->has_trap_at(bci, m, reason) != 0) {
3338     // Assume PerBytecodeTrapLimit==0, for a more conservative heuristic.
3339     // Also, if there are multiple reasons, or if there is no per-BCI record,
3340     // assume the worst.
3341     if (log())
3342       log()->elem("observe trap='%s' count='%d'",
3343                   Deoptimization::trap_reason_name(reason),
3344                   md->trap_count(reason));
3345     return true;
3346   } else {
3347     // Ignore method/bci and see if there have been too many globally.
3348     return too_many_traps(reason, md);
3349   }
3350 }
3351 
3352 // Less-accurate variant which does not require a method and bci.
3353 bool Compile::too_many_traps(Deoptimization::DeoptReason reason,
3354                              ciMethodData* logmd) {
3355   if (trap_count(reason) >= Deoptimization::per_method_trap_limit(reason)) {
3356     // Too many traps globally.
3357     // Note that we use cumulative trap_count, not just md->trap_count.
3358     if (log()) {
3359       int mcount = (logmd == NULL)? -1: (int)logmd->trap_count(reason);
3360       log()->elem("observe trap='%s' count='0' mcount='%d' ccount='%d'",
3361                   Deoptimization::trap_reason_name(reason),
3362                   mcount, trap_count(reason));
3363     }
3364     return true;
3365   } else {
3366     // The coast is clear.
3367     return false;
3368   }
3369 }
3370 
3371 //--------------------------too_many_recompiles--------------------------------
3372 // Report if there are too many recompiles at the current method and bci.
3373 // Consults PerBytecodeRecompilationCutoff and PerMethodRecompilationCutoff.
3374 // Is not eager to return true, since this will cause the compiler to use
3375 // Action_none for a trap point, to avoid too many recompilations.
3376 bool Compile::too_many_recompiles(ciMethod* method,
3377                                   int bci,
3378                                   Deoptimization::DeoptReason reason) {
3379   if (method->has_injected_profile()) {
3380     return false;
3381   }
3382   ciMethodData* md = method->method_data();
3383   if (md->is_empty()) {
3384     // Assume the trap has not occurred, or that it occurred only
3385     // because of a transient condition during start-up in the interpreter.
3386     return false;
3387   }
3388   // Pick a cutoff point well within PerBytecodeRecompilationCutoff.
3389   uint bc_cutoff = (uint) PerBytecodeRecompilationCutoff / 8;
3390   uint m_cutoff  = (uint) PerMethodRecompilationCutoff / 2 + 1;  // not zero
3391   Deoptimization::DeoptReason per_bc_reason
3392     = Deoptimization::reason_recorded_per_bytecode_if_any(reason);
3393   ciMethod* m = Deoptimization::reason_is_speculate(reason) ? this->method() : NULL;
3394   if ((per_bc_reason == Deoptimization::Reason_none
3395        || md->has_trap_at(bci, m, reason) != 0)
3396       // The trap frequency measure we care about is the recompile count:
3397       && md->trap_recompiled_at(bci, m)
3398       && md->overflow_recompile_count() >= bc_cutoff) {
3399     // Do not emit a trap here if it has already caused recompilations.
3400     // Also, if there are multiple reasons, or if there is no per-BCI record,
3401     // assume the worst.
3402     if (log())
3403       log()->elem("observe trap='%s recompiled' count='%d' recompiles2='%d'",
3404                   Deoptimization::trap_reason_name(reason),
3405                   md->trap_count(reason),
3406                   md->overflow_recompile_count());
3407     return true;
3408   } else if (trap_count(reason) != 0
3409              && decompile_count() >= m_cutoff) {
3410     // Too many recompiles globally, and we have seen this sort of trap.
3411     // Use cumulative decompile_count, not just md->decompile_count.
3412     if (log())
3413       log()->elem("observe trap='%s' count='%d' mcount='%d' decompiles='%d' mdecompiles='%d'",
3414                   Deoptimization::trap_reason_name(reason),
3415                   md->trap_count(reason), trap_count(reason),
3416                   md->decompile_count(), decompile_count());
3417     return true;
3418   } else {
3419     // The coast is clear.
3420     return false;
3421   }
3422 }
3423 
3424 // Compute when not to trap. Used by matching trap based nodes and
3425 // NullCheck optimization.
3426 void Compile::set_allowed_deopt_reasons() {
3427   _allowed_reasons = 0;
3428   if (is_method_compilation()) {
3429     for (int rs = (int)Deoptimization::Reason_none+1; rs < Compile::trapHistLength; rs++) {
3430       assert(rs < BitsPerInt, "recode bit map");
3431       if (!too_many_traps((Deoptimization::DeoptReason) rs)) {
3432         _allowed_reasons |= nth_bit(rs);
3433       }
3434     }
3435   }
3436 }
3437 
3438 #ifndef PRODUCT
3439 //------------------------------verify_graph_edges---------------------------
3440 // Walk the Graph and verify that there is a one-to-one correspondence
3441 // between Use-Def edges and Def-Use edges in the graph.
3442 void Compile::verify_graph_edges(bool no_dead_code) {
3443   if (VerifyGraphEdges) {
3444     ResourceArea *area = Thread::current()->resource_area();
3445     Unique_Node_List visited(area);
3446     // Call recursive graph walk to check edges
3447     _root->verify_edges(visited);
3448     if (no_dead_code) {
3449       // Now make sure that no visited node is used by an unvisited node.
3450       bool dead_nodes = false;
3451       Unique_Node_List checked(area);
3452       while (visited.size() > 0) {
3453         Node* n = visited.pop();
3454         checked.push(n);
3455         for (uint i = 0; i < n->outcnt(); i++) {
3456           Node* use = n->raw_out(i);
3457           if (checked.member(use))  continue;  // already checked
3458           if (visited.member(use))  continue;  // already in the graph
3459           if (use->is_Con())        continue;  // a dead ConNode is OK
3460           // At this point, we have found a dead node which is DU-reachable.
3461           if (!dead_nodes) {
3462             tty->print_cr("*** Dead nodes reachable via DU edges:");
3463             dead_nodes = true;
3464           }
3465           use->dump(2);
3466           tty->print_cr("---");
3467           checked.push(use);  // No repeats; pretend it is now checked.
3468         }
3469       }
3470       assert(!dead_nodes, "using nodes must be reachable from root");
3471     }
3472   }
3473 }
3474 
3475 // Verify GC barriers consistency
3476 // Currently supported:
3477 // - G1 pre-barriers (see GraphKit::g1_write_barrier_pre())
3478 void Compile::verify_barriers() {
3479   if (UseG1GC) {
3480     // Verify G1 pre-barriers
3481     const int marking_offset = in_bytes(JavaThread::satb_mark_queue_offset() + PtrQueue::byte_offset_of_active());
3482 
3483     ResourceArea *area = Thread::current()->resource_area();
3484     Unique_Node_List visited(area);
3485     Node_List worklist(area);
3486     // We're going to walk control flow backwards starting from the Root
3487     worklist.push(_root);
3488     while (worklist.size() > 0) {
3489       Node* x = worklist.pop();
3490       if (x == NULL || x == top()) continue;
3491       if (visited.member(x)) {
3492         continue;
3493       } else {
3494         visited.push(x);
3495       }
3496 
3497       if (x->is_Region()) {
3498         for (uint i = 1; i < x->req(); i++) {
3499           worklist.push(x->in(i));
3500         }
3501       } else {
3502         worklist.push(x->in(0));
3503         // We are looking for the pattern:
3504         //                            /->ThreadLocal
3505         // If->Bool->CmpI->LoadB->AddP->ConL(marking_offset)
3506         //              \->ConI(0)
3507         // We want to verify that the If and the LoadB have the same control
3508         // See GraphKit::g1_write_barrier_pre()
3509         if (x->is_If()) {
3510           IfNode *iff = x->as_If();
3511           if (iff->in(1)->is_Bool() && iff->in(1)->in(1)->is_Cmp()) {
3512             CmpNode *cmp = iff->in(1)->in(1)->as_Cmp();
3513             if (cmp->Opcode() == Op_CmpI && cmp->in(2)->is_Con() && cmp->in(2)->bottom_type()->is_int()->get_con() == 0
3514                 && cmp->in(1)->is_Load()) {
3515               LoadNode* load = cmp->in(1)->as_Load();
3516               if (load->Opcode() == Op_LoadB && load->in(2)->is_AddP() && load->in(2)->in(2)->Opcode() == Op_ThreadLocal
3517                   && load->in(2)->in(3)->is_Con()
3518                   && load->in(2)->in(3)->bottom_type()->is_intptr_t()->get_con() == marking_offset) {
3519 
3520                 Node* if_ctrl = iff->in(0);
3521                 Node* load_ctrl = load->in(0);
3522 
3523                 if (if_ctrl != load_ctrl) {
3524                   // Skip possible CProj->NeverBranch in infinite loops
3525                   if ((if_ctrl->is_Proj() && if_ctrl->Opcode() == Op_CProj)
3526                       && (if_ctrl->in(0)->is_MultiBranch() && if_ctrl->in(0)->Opcode() == Op_NeverBranch)) {
3527                     if_ctrl = if_ctrl->in(0)->in(0);
3528                   }
3529                 }
3530                 assert(load_ctrl != NULL && if_ctrl == load_ctrl, "controls must match");
3531               }
3532             }
3533           }
3534         }
3535       }
3536     }
3537   }
3538 }
3539 
3540 #endif
3541 
3542 // The Compile object keeps track of failure reasons separately from the ciEnv.
3543 // This is required because there is not quite a 1-1 relation between the
3544 // ciEnv and its compilation task and the Compile object.  Note that one
3545 // ciEnv might use two Compile objects, if C2Compiler::compile_method decides
3546 // to backtrack and retry without subsuming loads.  Other than this backtracking
3547 // behavior, the Compile's failure reason is quietly copied up to the ciEnv
3548 // by the logic in C2Compiler.
3549 void Compile::record_failure(const char* reason) {
3550   if (log() != NULL) {
3551     log()->elem("failure reason='%s' phase='compile'", reason);
3552   }
3553   if (_failure_reason == NULL) {
3554     // Record the first failure reason.
3555     _failure_reason = reason;
3556   }
3557 
3558   if (!C->failure_reason_is(C2Compiler::retry_no_subsuming_loads())) {
3559     C->print_method(PHASE_FAILURE);
3560   }
3561   _root = NULL;  // flush the graph, too
3562 }
3563 
3564 Compile::TracePhase::TracePhase(const char* name, elapsedTimer* accumulator)
3565   : TraceTime(name, accumulator, CITime, CITimeVerbose),
3566     _phase_name(name), _dolog(CITimeVerbose)
3567 {
3568   if (_dolog) {
3569     C = Compile::current();
3570     _log = C->log();
3571   } else {
3572     C = NULL;
3573     _log = NULL;
3574   }
3575   if (_log != NULL) {
3576     _log->begin_head("phase name='%s' nodes='%d' live='%d'", _phase_name, C->unique(), C->live_nodes());
3577     _log->stamp();
3578     _log->end_head();
3579   }
3580 }
3581 
3582 Compile::TracePhase::~TracePhase() {
3583 
3584   C = Compile::current();
3585   if (_dolog) {
3586     _log = C->log();
3587   } else {
3588     _log = NULL;
3589   }
3590 
3591 #ifdef ASSERT
3592   if (PrintIdealNodeCount) {
3593     tty->print_cr("phase name='%s' nodes='%d' live='%d' live_graph_walk='%d'",
3594                   _phase_name, C->unique(), C->live_nodes(), C->count_live_nodes_by_graph_walk());
3595   }
3596 
3597   if (VerifyIdealNodeCount) {
3598     Compile::current()->print_missing_nodes();
3599   }
3600 #endif
3601 
3602   if (_log != NULL) {
3603     _log->done("phase name='%s' nodes='%d' live='%d'", _phase_name, C->unique(), C->live_nodes());
3604   }
3605 }
3606 
3607 //=============================================================================
3608 // Two Constant's are equal when the type and the value are equal.
3609 bool Compile::Constant::operator==(const Constant& other) {
3610   if (type()          != other.type()         )  return false;
3611   if (can_be_reused() != other.can_be_reused())  return false;
3612   // For floating point values we compare the bit pattern.
3613   switch (type()) {
3614   case T_FLOAT:   return (_v._value.i == other._v._value.i);
3615   case T_LONG:
3616   case T_DOUBLE:  return (_v._value.j == other._v._value.j);
3617   case T_OBJECT:
3618   case T_ADDRESS: return (_v._value.l == other._v._value.l);
3619   case T_VOID:    return (_v._value.l == other._v._value.l);  // jump-table entries
3620   case T_METADATA: return (_v._metadata == other._v._metadata);
3621   default: ShouldNotReachHere();
3622   }
3623   return false;
3624 }
3625 
3626 static int type_to_size_in_bytes(BasicType t) {
3627   switch (t) {
3628   case T_LONG:    return sizeof(jlong  );
3629   case T_FLOAT:   return sizeof(jfloat );
3630   case T_DOUBLE:  return sizeof(jdouble);
3631   case T_METADATA: return sizeof(Metadata*);
3632     // We use T_VOID as marker for jump-table entries (labels) which
3633     // need an internal word relocation.
3634   case T_VOID:
3635   case T_ADDRESS:
3636   case T_OBJECT:  return sizeof(jobject);
3637   }
3638 
3639   ShouldNotReachHere();
3640   return -1;
3641 }
3642 
3643 int Compile::ConstantTable::qsort_comparator(Constant* a, Constant* b) {
3644   // sort descending
3645   if (a->freq() > b->freq())  return -1;
3646   if (a->freq() < b->freq())  return  1;
3647   return 0;
3648 }
3649 
3650 void Compile::ConstantTable::calculate_offsets_and_size() {
3651   // First, sort the array by frequencies.
3652   _constants.sort(qsort_comparator);
3653 
3654 #ifdef ASSERT
3655   // Make sure all jump-table entries were sorted to the end of the
3656   // array (they have a negative frequency).
3657   bool found_void = false;
3658   for (int i = 0; i < _constants.length(); i++) {
3659     Constant con = _constants.at(i);
3660     if (con.type() == T_VOID)
3661       found_void = true;  // jump-tables
3662     else
3663       assert(!found_void, "wrong sorting");
3664   }
3665 #endif
3666 
3667   int offset = 0;
3668   for (int i = 0; i < _constants.length(); i++) {
3669     Constant* con = _constants.adr_at(i);
3670 
3671     // Align offset for type.
3672     int typesize = type_to_size_in_bytes(con->type());
3673     offset = align_size_up(offset, typesize);
3674     con->set_offset(offset);   // set constant's offset
3675 
3676     if (con->type() == T_VOID) {
3677       MachConstantNode* n = (MachConstantNode*) con->get_jobject();
3678       offset = offset + typesize * n->outcnt();  // expand jump-table
3679     } else {
3680       offset = offset + typesize;
3681     }
3682   }
3683 
3684   // Align size up to the next section start (which is insts; see
3685   // CodeBuffer::align_at_start).
3686   assert(_size == -1, "already set?");
3687   _size = align_size_up(offset, CodeEntryAlignment);
3688 }
3689 
3690 void Compile::ConstantTable::emit(CodeBuffer& cb) {
3691   MacroAssembler _masm(&cb);
3692   for (int i = 0; i < _constants.length(); i++) {
3693     Constant con = _constants.at(i);
3694     address constant_addr;
3695     switch (con.type()) {
3696     case T_LONG:   constant_addr = _masm.long_constant(  con.get_jlong()  ); break;
3697     case T_FLOAT:  constant_addr = _masm.float_constant( con.get_jfloat() ); break;
3698     case T_DOUBLE: constant_addr = _masm.double_constant(con.get_jdouble()); break;
3699     case T_OBJECT: {
3700       jobject obj = con.get_jobject();
3701       int oop_index = _masm.oop_recorder()->find_index(obj);
3702       constant_addr = _masm.address_constant((address) obj, oop_Relocation::spec(oop_index));
3703       break;
3704     }
3705     case T_ADDRESS: {
3706       address addr = (address) con.get_jobject();
3707       constant_addr = _masm.address_constant(addr);
3708       break;
3709     }
3710     // We use T_VOID as marker for jump-table entries (labels) which
3711     // need an internal word relocation.
3712     case T_VOID: {
3713       MachConstantNode* n = (MachConstantNode*) con.get_jobject();
3714       // Fill the jump-table with a dummy word.  The real value is
3715       // filled in later in fill_jump_table.
3716       address dummy = (address) n;
3717       constant_addr = _masm.address_constant(dummy);
3718       // Expand jump-table
3719       for (uint i = 1; i < n->outcnt(); i++) {
3720         address temp_addr = _masm.address_constant(dummy + i);
3721         assert(temp_addr, "consts section too small");
3722       }
3723       break;
3724     }
3725     case T_METADATA: {
3726       Metadata* obj = con.get_metadata();
3727       int metadata_index = _masm.oop_recorder()->find_index(obj);
3728       constant_addr = _masm.address_constant((address) obj, metadata_Relocation::spec(metadata_index));
3729       break;
3730     }
3731     default: ShouldNotReachHere();
3732     }
3733     assert(constant_addr, "consts section too small");
3734     assert((constant_addr - _masm.code()->consts()->start()) == con.offset(),
3735             err_msg_res("must be: %d == %d", (int) (constant_addr - _masm.code()->consts()->start()), (int)(con.offset())));
3736   }
3737 }
3738 
3739 int Compile::ConstantTable::find_offset(Constant& con) const {
3740   int idx = _constants.find(con);
3741   assert(idx != -1, "constant must be in constant table");
3742   int offset = _constants.at(idx).offset();
3743   assert(offset != -1, "constant table not emitted yet?");
3744   return offset;
3745 }
3746 
3747 void Compile::ConstantTable::add(Constant& con) {
3748   if (con.can_be_reused()) {
3749     int idx = _constants.find(con);
3750     if (idx != -1 && _constants.at(idx).can_be_reused()) {
3751       _constants.adr_at(idx)->inc_freq(con.freq());  // increase the frequency by the current value
3752       return;
3753     }
3754   }
3755   (void) _constants.append(con);
3756 }
3757 
3758 Compile::Constant Compile::ConstantTable::add(MachConstantNode* n, BasicType type, jvalue value) {
3759   Block* b = Compile::current()->cfg()->get_block_for_node(n);
3760   Constant con(type, value, b->_freq);
3761   add(con);
3762   return con;
3763 }
3764 
3765 Compile::Constant Compile::ConstantTable::add(Metadata* metadata) {
3766   Constant con(metadata);
3767   add(con);
3768   return con;
3769 }
3770 
3771 Compile::Constant Compile::ConstantTable::add(MachConstantNode* n, MachOper* oper) {
3772   jvalue value;
3773   BasicType type = oper->type()->basic_type();
3774   switch (type) {
3775   case T_LONG:    value.j = oper->constantL(); break;
3776   case T_FLOAT:   value.f = oper->constantF(); break;
3777   case T_DOUBLE:  value.d = oper->constantD(); break;
3778   case T_OBJECT:
3779   case T_ADDRESS: value.l = (jobject) oper->constant(); break;
3780   case T_METADATA: return add((Metadata*)oper->constant()); break;
3781   default: guarantee(false, err_msg_res("unhandled type: %s", type2name(type)));
3782   }
3783   return add(n, type, value);
3784 }
3785 
3786 Compile::Constant Compile::ConstantTable::add_jump_table(MachConstantNode* n) {
3787   jvalue value;
3788   // We can use the node pointer here to identify the right jump-table
3789   // as this method is called from Compile::Fill_buffer right before
3790   // the MachNodes are emitted and the jump-table is filled (means the
3791   // MachNode pointers do not change anymore).
3792   value.l = (jobject) n;
3793   Constant con(T_VOID, value, next_jump_table_freq(), false);  // Labels of a jump-table cannot be reused.
3794   add(con);
3795   return con;
3796 }
3797 
3798 void Compile::ConstantTable::fill_jump_table(CodeBuffer& cb, MachConstantNode* n, GrowableArray<Label*> labels) const {
3799   // If called from Compile::scratch_emit_size do nothing.
3800   if (Compile::current()->in_scratch_emit_size())  return;
3801 
3802   assert(labels.is_nonempty(), "must be");
3803   assert((uint) labels.length() == n->outcnt(), err_msg_res("must be equal: %d == %d", labels.length(), n->outcnt()));
3804 
3805   // Since MachConstantNode::constant_offset() also contains
3806   // table_base_offset() we need to subtract the table_base_offset()
3807   // to get the plain offset into the constant table.
3808   int offset = n->constant_offset() - table_base_offset();
3809 
3810   MacroAssembler _masm(&cb);
3811   address* jump_table_base = (address*) (_masm.code()->consts()->start() + offset);
3812 
3813   for (uint i = 0; i < n->outcnt(); i++) {
3814     address* constant_addr = &jump_table_base[i];
3815     assert(*constant_addr == (((address) n) + i), err_msg_res("all jump-table entries must contain adjusted node pointer: " INTPTR_FORMAT " == " INTPTR_FORMAT, p2i(*constant_addr), p2i(((address) n) + i)));
3816     *constant_addr = cb.consts()->target(*labels.at(i), (address) constant_addr);
3817     cb.consts()->relocate((address) constant_addr, relocInfo::internal_word_type);
3818   }
3819 }
3820 
3821 //----------------------------static_subtype_check-----------------------------
3822 // Shortcut important common cases when superklass is exact:
3823 // (0) superklass is java.lang.Object (can occur in reflective code)
3824 // (1) subklass is already limited to a subtype of superklass => always ok
3825 // (2) subklass does not overlap with superklass => always fail
3826 // (3) superklass has NO subtypes and we can check with a simple compare.
3827 int Compile::static_subtype_check(ciKlass* superk, ciKlass* subk) {
3828   if (StressReflectiveCode) {
3829     return SSC_full_test;       // Let caller generate the general case.
3830   }
3831 
3832   if (superk == env()->Object_klass()) {
3833     return SSC_always_true;     // (0) this test cannot fail
3834   }
3835 
3836   ciType* superelem = superk;
3837   if (superelem->is_array_klass())
3838     superelem = superelem->as_array_klass()->base_element_type();
3839 
3840   if (!subk->is_interface()) {  // cannot trust static interface types yet
3841     if (subk->is_subtype_of(superk)) {
3842       return SSC_always_true;   // (1) false path dead; no dynamic test needed
3843     }
3844     if (!(superelem->is_klass() && superelem->as_klass()->is_interface()) &&
3845         !superk->is_subtype_of(subk)) {
3846       return SSC_always_false;
3847     }
3848   }
3849 
3850   // If casting to an instance klass, it must have no subtypes
3851   if (superk->is_interface()) {
3852     // Cannot trust interfaces yet.
3853     // %%% S.B. superk->nof_implementors() == 1
3854   } else if (superelem->is_instance_klass()) {
3855     ciInstanceKlass* ik = superelem->as_instance_klass();
3856     if (!ik->has_subklass() && !ik->is_interface()) {
3857       if (!ik->is_final()) {
3858         // Add a dependency if there is a chance of a later subclass.
3859         dependencies()->assert_leaf_type(ik);
3860       }
3861       return SSC_easy_test;     // (3) caller can do a simple ptr comparison
3862     }
3863   } else {
3864     // A primitive array type has no subtypes.
3865     return SSC_easy_test;       // (3) caller can do a simple ptr comparison
3866   }
3867 
3868   return SSC_full_test;
3869 }
3870 
3871 Node* Compile::conv_I2X_index(PhaseGVN *phase, Node* idx, const TypeInt* sizetype) {
3872 #ifdef _LP64
3873   // The scaled index operand to AddP must be a clean 64-bit value.
3874   // Java allows a 32-bit int to be incremented to a negative
3875   // value, which appears in a 64-bit register as a large
3876   // positive number.  Using that large positive number as an
3877   // operand in pointer arithmetic has bad consequences.
3878   // On the other hand, 32-bit overflow is rare, and the possibility
3879   // can often be excluded, if we annotate the ConvI2L node with
3880   // a type assertion that its value is known to be a small positive
3881   // number.  (The prior range check has ensured this.)
3882   // This assertion is used by ConvI2LNode::Ideal.
3883   int index_max = max_jint - 1;  // array size is max_jint, index is one less
3884   if (sizetype != NULL)  index_max = sizetype->_hi - 1;
3885   const TypeLong* lidxtype = TypeLong::make(CONST64(0), index_max, Type::WidenMax);
3886   idx = phase->transform(new ConvI2LNode(idx, lidxtype));
3887 #endif
3888   return idx;
3889 }
3890 
3891 // The message about the current inlining is accumulated in
3892 // _print_inlining_stream and transfered into the _print_inlining_list
3893 // once we know whether inlining succeeds or not. For regular
3894 // inlining, messages are appended to the buffer pointed by
3895 // _print_inlining_idx in the _print_inlining_list. For late inlining,
3896 // a new buffer is added after _print_inlining_idx in the list. This
3897 // way we can update the inlining message for late inlining call site
3898 // when the inlining is attempted again.
3899 void Compile::print_inlining_init() {
3900   if (print_inlining() || print_intrinsics()) {
3901     _print_inlining_stream = new stringStream();
3902     _print_inlining_list = new (comp_arena())GrowableArray<PrintInliningBuffer>(comp_arena(), 1, 1, PrintInliningBuffer());
3903   }
3904 }
3905 
3906 void Compile::print_inlining_reinit() {
3907   if (print_inlining() || print_intrinsics()) {
3908     // Re allocate buffer when we change ResourceMark
3909     _print_inlining_stream = new stringStream();
3910   }
3911 }
3912 
3913 void Compile::print_inlining_reset() {
3914   _print_inlining_stream->reset();
3915 }
3916 
3917 void Compile::print_inlining_commit() {
3918   assert(print_inlining() || print_intrinsics(), "PrintInlining off?");
3919   // Transfer the message from _print_inlining_stream to the current
3920   // _print_inlining_list buffer and clear _print_inlining_stream.
3921   _print_inlining_list->at(_print_inlining_idx).ss()->write(_print_inlining_stream->as_string(), _print_inlining_stream->size());
3922   print_inlining_reset();
3923 }
3924 
3925 void Compile::print_inlining_push() {
3926   // Add new buffer to the _print_inlining_list at current position
3927   _print_inlining_idx++;
3928   _print_inlining_list->insert_before(_print_inlining_idx, PrintInliningBuffer());
3929 }
3930 
3931 Compile::PrintInliningBuffer& Compile::print_inlining_current() {
3932   return _print_inlining_list->at(_print_inlining_idx);
3933 }
3934 
3935 void Compile::print_inlining_update(CallGenerator* cg) {
3936   if (print_inlining() || print_intrinsics()) {
3937     if (!cg->is_late_inline()) {
3938       if (print_inlining_current().cg() != NULL) {
3939         print_inlining_push();
3940       }
3941       print_inlining_commit();
3942     } else {
3943       if (print_inlining_current().cg() != cg &&
3944           (print_inlining_current().cg() != NULL ||
3945            print_inlining_current().ss()->size() != 0)) {
3946         print_inlining_push();
3947       }
3948       print_inlining_commit();
3949       print_inlining_current().set_cg(cg);
3950     }
3951   }
3952 }
3953 
3954 void Compile::print_inlining_move_to(CallGenerator* cg) {
3955   // We resume inlining at a late inlining call site. Locate the
3956   // corresponding inlining buffer so that we can update it.
3957   if (print_inlining()) {
3958     for (int i = 0; i < _print_inlining_list->length(); i++) {
3959       if (_print_inlining_list->adr_at(i)->cg() == cg) {
3960         _print_inlining_idx = i;
3961         return;
3962       }
3963     }
3964     ShouldNotReachHere();
3965   }
3966 }
3967 
3968 void Compile::print_inlining_update_delayed(CallGenerator* cg) {
3969   if (print_inlining()) {
3970     assert(_print_inlining_stream->size() > 0, "missing inlining msg");
3971     assert(print_inlining_current().cg() == cg, "wrong entry");
3972     // replace message with new message
3973     _print_inlining_list->at_put(_print_inlining_idx, PrintInliningBuffer());
3974     print_inlining_commit();
3975     print_inlining_current().set_cg(cg);
3976   }
3977 }
3978 
3979 void Compile::print_inlining_assert_ready() {
3980   assert(!_print_inlining || _print_inlining_stream->size() == 0, "loosing data");
3981 }
3982 
3983 void Compile::process_print_inlining() {
3984   bool do_print_inlining = print_inlining() || print_intrinsics();
3985   if (do_print_inlining || log() != NULL) {
3986     // Print inlining message for candidates that we couldn't inline
3987     // for lack of space
3988     for (int i = 0; i < _late_inlines.length(); i++) {
3989       CallGenerator* cg = _late_inlines.at(i);
3990       if (!cg->is_mh_late_inline()) {
3991         const char* msg = "live nodes > LiveNodeCountInliningCutoff";
3992         if (do_print_inlining) {
3993           cg->print_inlining_late(msg);
3994         }
3995         log_late_inline_failure(cg, msg);
3996       }
3997     }
3998   }
3999   if (do_print_inlining) {
4000     ResourceMark rm;
4001     stringStream ss;
4002     for (int i = 0; i < _print_inlining_list->length(); i++) {
4003       ss.print("%s", _print_inlining_list->adr_at(i)->ss()->as_string());
4004     }
4005     size_t end = ss.size();
4006     _print_inlining_output = NEW_ARENA_ARRAY(comp_arena(), char, end+1);
4007     strncpy(_print_inlining_output, ss.base(), end+1);
4008     _print_inlining_output[end] = 0;
4009   }
4010 }
4011 
4012 void Compile::dump_print_inlining() {
4013   if (_print_inlining_output != NULL) {
4014     tty->print_raw(_print_inlining_output);
4015   }
4016 }
4017 
4018 void Compile::log_late_inline(CallGenerator* cg) {
4019   if (log() != NULL) {
4020     log()->head("late_inline method='%d'  inline_id='" JLONG_FORMAT "'", log()->identify(cg->method()),
4021                 cg->unique_id());
4022     JVMState* p = cg->call_node()->jvms();
4023     while (p != NULL) {
4024       log()->elem("jvms bci='%d' method='%d'", p->bci(), log()->identify(p->method()));
4025       p = p->caller();
4026     }
4027     log()->tail("late_inline");
4028   }
4029 }
4030 
4031 void Compile::log_late_inline_failure(CallGenerator* cg, const char* msg) {
4032   log_late_inline(cg);
4033   if (log() != NULL) {
4034     log()->inline_fail(msg);
4035   }
4036 }
4037 
4038 void Compile::log_inline_id(CallGenerator* cg) {
4039   if (log() != NULL) {
4040     // The LogCompilation tool needs a unique way to identify late
4041     // inline call sites. This id must be unique for this call site in
4042     // this compilation. Try to have it unique across compilations as
4043     // well because it can be convenient when grepping through the log
4044     // file.
4045     // Distinguish OSR compilations from others in case CICountOSR is
4046     // on.
4047     jlong id = ((jlong)unique()) + (((jlong)compile_id()) << 33) + (CICountOSR && is_osr_compilation() ? ((jlong)1) << 32 : 0);
4048     cg->set_unique_id(id);
4049     log()->elem("inline_id id='" JLONG_FORMAT "'", id);
4050   }
4051 }
4052 
4053 void Compile::log_inline_failure(const char* msg) {
4054   if (C->log() != NULL) {
4055     C->log()->inline_fail(msg);
4056   }
4057 }
4058 
4059 
4060 // Dump inlining replay data to the stream.
4061 // Don't change thread state and acquire any locks.
4062 void Compile::dump_inline_data(outputStream* out) {
4063   InlineTree* inl_tree = ilt();
4064   if (inl_tree != NULL) {
4065     out->print(" inline %d", inl_tree->count());
4066     inl_tree->dump_replay_data(out);
4067   }
4068 }
4069 
4070 int Compile::cmp_expensive_nodes(Node* n1, Node* n2) {
4071   if (n1->Opcode() < n2->Opcode())      return -1;
4072   else if (n1->Opcode() > n2->Opcode()) return 1;
4073 
4074   assert(n1->req() == n2->req(), err_msg_res("can't compare %s nodes: n1->req() = %d, n2->req() = %d", NodeClassNames[n1->Opcode()], n1->req(), n2->req()));
4075   for (uint i = 1; i < n1->req(); i++) {
4076     if (n1->in(i) < n2->in(i))      return -1;
4077     else if (n1->in(i) > n2->in(i)) return 1;
4078   }
4079 
4080   return 0;
4081 }
4082 
4083 int Compile::cmp_expensive_nodes(Node** n1p, Node** n2p) {
4084   Node* n1 = *n1p;
4085   Node* n2 = *n2p;
4086 
4087   return cmp_expensive_nodes(n1, n2);
4088 }
4089 
4090 void Compile::sort_expensive_nodes() {
4091   if (!expensive_nodes_sorted()) {
4092     _expensive_nodes->sort(cmp_expensive_nodes);
4093   }
4094 }
4095 
4096 bool Compile::expensive_nodes_sorted() const {
4097   for (int i = 1; i < _expensive_nodes->length(); i++) {
4098     if (cmp_expensive_nodes(_expensive_nodes->adr_at(i), _expensive_nodes->adr_at(i-1)) < 0) {
4099       return false;
4100     }
4101   }
4102   return true;
4103 }
4104 
4105 bool Compile::should_optimize_expensive_nodes(PhaseIterGVN &igvn) {
4106   if (_expensive_nodes->length() == 0) {
4107     return false;
4108   }
4109 
4110   assert(OptimizeExpensiveOps, "optimization off?");
4111 
4112   // Take this opportunity to remove dead nodes from the list
4113   int j = 0;
4114   for (int i = 0; i < _expensive_nodes->length(); i++) {
4115     Node* n = _expensive_nodes->at(i);
4116     if (!n->is_unreachable(igvn)) {
4117       assert(n->is_expensive(), "should be expensive");
4118       _expensive_nodes->at_put(j, n);
4119       j++;
4120     }
4121   }
4122   _expensive_nodes->trunc_to(j);
4123 
4124   // Then sort the list so that similar nodes are next to each other
4125   // and check for at least two nodes of identical kind with same data
4126   // inputs.
4127   sort_expensive_nodes();
4128 
4129   for (int i = 0; i < _expensive_nodes->length()-1; i++) {
4130     if (cmp_expensive_nodes(_expensive_nodes->adr_at(i), _expensive_nodes->adr_at(i+1)) == 0) {
4131       return true;
4132     }
4133   }
4134 
4135   return false;
4136 }
4137 
4138 void Compile::cleanup_expensive_nodes(PhaseIterGVN &igvn) {
4139   if (_expensive_nodes->length() == 0) {
4140     return;
4141   }
4142 
4143   assert(OptimizeExpensiveOps, "optimization off?");
4144 
4145   // Sort to bring similar nodes next to each other and clear the
4146   // control input of nodes for which there's only a single copy.
4147   sort_expensive_nodes();
4148 
4149   int j = 0;
4150   int identical = 0;
4151   int i = 0;
4152   bool modified = false;
4153   for (; i < _expensive_nodes->length()-1; i++) {
4154     assert(j <= i, "can't write beyond current index");
4155     if (_expensive_nodes->at(i)->Opcode() == _expensive_nodes->at(i+1)->Opcode()) {
4156       identical++;
4157       _expensive_nodes->at_put(j++, _expensive_nodes->at(i));
4158       continue;
4159     }
4160     if (identical > 0) {
4161       _expensive_nodes->at_put(j++, _expensive_nodes->at(i));
4162       identical = 0;
4163     } else {
4164       Node* n = _expensive_nodes->at(i);
4165       igvn.replace_input_of(n, 0, NULL);
4166       igvn.hash_insert(n);
4167       modified = true;
4168     }
4169   }
4170   if (identical > 0) {
4171     _expensive_nodes->at_put(j++, _expensive_nodes->at(i));
4172   } else if (_expensive_nodes->length() >= 1) {
4173     Node* n = _expensive_nodes->at(i);
4174     igvn.replace_input_of(n, 0, NULL);
4175     igvn.hash_insert(n);
4176     modified = true;
4177   }
4178   _expensive_nodes->trunc_to(j);
4179   if (modified) {
4180     igvn.optimize();
4181   }
4182 }
4183 
4184 void Compile::add_expensive_node(Node * n) {
4185   assert(!_expensive_nodes->contains(n), "duplicate entry in expensive list");
4186   assert(n->is_expensive(), "expensive nodes with non-null control here only");
4187   assert(!n->is_CFG() && !n->is_Mem(), "no cfg or memory nodes here");
4188   if (OptimizeExpensiveOps) {
4189     _expensive_nodes->append(n);
4190   } else {
4191     // Clear control input and let IGVN optimize expensive nodes if
4192     // OptimizeExpensiveOps is off.
4193     n->set_req(0, NULL);
4194   }
4195 }
4196 
4197 /**
4198  * Remove the speculative part of types and clean up the graph
4199  */
4200 void Compile::remove_speculative_types(PhaseIterGVN &igvn) {
4201   if (UseTypeSpeculation) {
4202     Unique_Node_List worklist;
4203     worklist.push(root());
4204     int modified = 0;
4205     // Go over all type nodes that carry a speculative type, drop the
4206     // speculative part of the type and enqueue the node for an igvn
4207     // which may optimize it out.
4208     for (uint next = 0; next < worklist.size(); ++next) {
4209       Node *n  = worklist.at(next);
4210       if (n->is_Type()) {
4211         TypeNode* tn = n->as_Type();
4212         const Type* t = tn->type();
4213         const Type* t_no_spec = t->remove_speculative();
4214         if (t_no_spec != t) {
4215           bool in_hash = igvn.hash_delete(n);
4216           assert(in_hash, "node should be in igvn hash table");
4217           tn->set_type(t_no_spec);
4218           igvn.hash_insert(n);
4219           igvn._worklist.push(n); // give it a chance to go away
4220           modified++;
4221         }
4222       }
4223       uint max = n->len();
4224       for( uint i = 0; i < max; ++i ) {
4225         Node *m = n->in(i);
4226         if (not_a_node(m))  continue;
4227         worklist.push(m);
4228       }
4229     }
4230     // Drop the speculative part of all types in the igvn's type table
4231     igvn.remove_speculative_types();
4232     if (modified > 0) {
4233       igvn.optimize();
4234     }
4235 #ifdef ASSERT
4236     // Verify that after the IGVN is over no speculative type has resurfaced
4237     worklist.clear();
4238     worklist.push(root());
4239     for (uint next = 0; next < worklist.size(); ++next) {
4240       Node *n  = worklist.at(next);
4241       const Type* t = igvn.type_or_null(n);
4242       assert((t == NULL) || (t == t->remove_speculative()), "no more speculative types");
4243       if (n->is_Type()) {
4244         t = n->as_Type()->type();
4245         assert(t == t->remove_speculative(), "no more speculative types");
4246       }
4247       uint max = n->len();
4248       for( uint i = 0; i < max; ++i ) {
4249         Node *m = n->in(i);
4250         if (not_a_node(m))  continue;
4251         worklist.push(m);
4252       }
4253     }
4254     igvn.check_no_speculative_types();
4255 #endif
4256   }
4257 }
4258 
4259 // Auxiliary method to support randomized stressing/fuzzing.
4260 //
4261 // This method can be called the arbitrary number of times, with current count
4262 // as the argument. The logic allows selecting a single candidate from the
4263 // running list of candidates as follows:
4264 //    int count = 0;
4265 //    Cand* selected = null;
4266 //    while(cand = cand->next()) {
4267 //      if (randomized_select(++count)) {
4268 //        selected = cand;
4269 //      }
4270 //    }
4271 //
4272 // Including count equalizes the chances any candidate is "selected".
4273 // This is useful when we don't have the complete list of candidates to choose
4274 // from uniformly. In this case, we need to adjust the randomicity of the
4275 // selection, or else we will end up biasing the selection towards the latter
4276 // candidates.
4277 //
4278 // Quick back-envelope calculation shows that for the list of n candidates
4279 // the equal probability for the candidate to persist as "best" can be
4280 // achieved by replacing it with "next" k-th candidate with the probability
4281 // of 1/k. It can be easily shown that by the end of the run, the
4282 // probability for any candidate is converged to 1/n, thus giving the
4283 // uniform distribution among all the candidates.
4284 //
4285 // We don't care about the domain size as long as (RANDOMIZED_DOMAIN / count) is large.
4286 #define RANDOMIZED_DOMAIN_POW 29
4287 #define RANDOMIZED_DOMAIN (1 << RANDOMIZED_DOMAIN_POW)
4288 #define RANDOMIZED_DOMAIN_MASK ((1 << (RANDOMIZED_DOMAIN_POW + 1)) - 1)
4289 bool Compile::randomized_select(int count) {
4290   assert(count > 0, "only positive");
4291   return (os::random() & RANDOMIZED_DOMAIN_MASK) < (RANDOMIZED_DOMAIN / count);
4292 }