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/compileLog.hpp"
  33 #include "compiler/disassembler.hpp"
  34 #include "compiler/oopMap.hpp"
  35 #include "opto/addnode.hpp"
  36 #include "opto/block.hpp"
  37 #include "opto/c2compiler.hpp"
  38 #include "opto/callGenerator.hpp"
  39 #include "opto/callnode.hpp"
  40 #include "opto/cfgnode.hpp"
  41 #include "opto/chaitin.hpp"
  42 #include "opto/compile.hpp"
  43 #include "opto/connode.hpp"
  44 #include "opto/divnode.hpp"
  45 #include "opto/escape.hpp"
  46 #include "opto/idealGraphPrinter.hpp"
  47 #include "opto/loopnode.hpp"
  48 #include "opto/machnode.hpp"
  49 #include "opto/macro.hpp"
  50 #include "opto/matcher.hpp"
  51 #include "opto/mathexactnode.hpp"
  52 #include "opto/memnode.hpp"
  53 #include "opto/mulnode.hpp"
  54 #include "opto/node.hpp"
  55 #include "opto/opcodes.hpp"
  56 #include "opto/output.hpp"
  57 #include "opto/parse.hpp"
  58 #include "opto/phaseX.hpp"
  59 #include "opto/rootnode.hpp"
  60 #include "opto/runtime.hpp"
  61 #include "opto/stringopts.hpp"
  62 #include "opto/type.hpp"
  63 #include "opto/vectornode.hpp"
  64 #include "runtime/arguments.hpp"
  65 #include "runtime/signature.hpp"
  66 #include "runtime/stubRoutines.hpp"
  67 #include "runtime/timer.hpp"
  68 #include "trace/tracing.hpp"
  69 #include "utilities/copy.hpp"
  70 #if defined AD_MD_HPP
  71 # include AD_MD_HPP
  72 #elif defined TARGET_ARCH_MODEL_x86_32
  73 # include "adfiles/ad_x86_32.hpp"
  74 #elif defined TARGET_ARCH_MODEL_x86_64
  75 # include "adfiles/ad_x86_64.hpp"
  76 #elif defined TARGET_ARCH_MODEL_sparc
  77 # include "adfiles/ad_sparc.hpp"
  78 #elif defined TARGET_ARCH_MODEL_zero
  79 # include "adfiles/ad_zero.hpp"
  80 #elif defined TARGET_ARCH_MODEL_ppc_64
  81 # include "adfiles/ad_ppc_64.hpp"
  82 #endif
  83 
  84 
  85 // -------------------- Compile::mach_constant_base_node -----------------------
  86 // Constant table base node singleton.
  87 MachConstantBaseNode* Compile::mach_constant_base_node() {
  88   if (_mach_constant_base_node == NULL) {
  89     _mach_constant_base_node = new (C) MachConstantBaseNode();
  90     _mach_constant_base_node->add_req(C->root());
  91   }
  92   return _mach_constant_base_node;
  93 }
  94 
  95 
  96 /// Support for intrinsics.
  97 
  98 // Return the index at which m must be inserted (or already exists).
  99 // The sort order is by the address of the ciMethod, with is_virtual as minor key.
 100 int Compile::intrinsic_insertion_index(ciMethod* m, bool is_virtual) {
 101 #ifdef ASSERT
 102   for (int i = 1; i < _intrinsics->length(); i++) {
 103     CallGenerator* cg1 = _intrinsics->at(i-1);
 104     CallGenerator* cg2 = _intrinsics->at(i);
 105     assert(cg1->method() != cg2->method()
 106            ? cg1->method()     < cg2->method()
 107            : cg1->is_virtual() < cg2->is_virtual(),
 108            "compiler intrinsics list must stay sorted");
 109   }
 110 #endif
 111   // Binary search sorted list, in decreasing intervals [lo, hi].
 112   int lo = 0, hi = _intrinsics->length()-1;
 113   while (lo <= hi) {
 114     int mid = (uint)(hi + lo) / 2;
 115     ciMethod* mid_m = _intrinsics->at(mid)->method();
 116     if (m < mid_m) {
 117       hi = mid-1;
 118     } else if (m > mid_m) {
 119       lo = mid+1;
 120     } else {
 121       // look at minor sort key
 122       bool mid_virt = _intrinsics->at(mid)->is_virtual();
 123       if (is_virtual < mid_virt) {
 124         hi = mid-1;
 125       } else if (is_virtual > mid_virt) {
 126         lo = mid+1;
 127       } else {
 128         return mid;  // exact match
 129       }
 130     }
 131   }
 132   return lo;  // inexact match
 133 }
 134 
 135 void Compile::register_intrinsic(CallGenerator* cg) {
 136   if (_intrinsics == NULL) {
 137     _intrinsics = new (comp_arena())GrowableArray<CallGenerator*>(comp_arena(), 60, 0, NULL);
 138   }
 139   // This code is stolen from ciObjectFactory::insert.
 140   // Really, GrowableArray should have methods for
 141   // insert_at, remove_at, and binary_search.
 142   int len = _intrinsics->length();
 143   int index = intrinsic_insertion_index(cg->method(), cg->is_virtual());
 144   if (index == len) {
 145     _intrinsics->append(cg);
 146   } else {
 147 #ifdef ASSERT
 148     CallGenerator* oldcg = _intrinsics->at(index);
 149     assert(oldcg->method() != cg->method() || oldcg->is_virtual() != cg->is_virtual(), "don't register twice");
 150 #endif
 151     _intrinsics->append(_intrinsics->at(len-1));
 152     int pos;
 153     for (pos = len-2; pos >= index; pos--) {
 154       _intrinsics->at_put(pos+1,_intrinsics->at(pos));
 155     }
 156     _intrinsics->at_put(index, cg);
 157   }
 158   assert(find_intrinsic(cg->method(), cg->is_virtual()) == cg, "registration worked");
 159 }
 160 
 161 CallGenerator* Compile::find_intrinsic(ciMethod* m, bool is_virtual) {
 162   assert(m->is_loaded(), "don't try this on unloaded methods");
 163   if (_intrinsics != NULL) {
 164     int index = intrinsic_insertion_index(m, is_virtual);
 165     if (index < _intrinsics->length()
 166         && _intrinsics->at(index)->method() == m
 167         && _intrinsics->at(index)->is_virtual() == is_virtual) {
 168       return _intrinsics->at(index);
 169     }
 170   }
 171   // Lazily create intrinsics for intrinsic IDs well-known in the runtime.
 172   if (m->intrinsic_id() != vmIntrinsics::_none &&
 173       m->intrinsic_id() <= vmIntrinsics::LAST_COMPILER_INLINE) {
 174     CallGenerator* cg = make_vm_intrinsic(m, is_virtual);
 175     if (cg != NULL) {
 176       // Save it for next time:
 177       register_intrinsic(cg);
 178       return cg;
 179     } else {
 180       gather_intrinsic_statistics(m->intrinsic_id(), is_virtual, _intrinsic_disabled);
 181     }
 182   }
 183   return NULL;
 184 }
 185 
 186 // Compile:: register_library_intrinsics and make_vm_intrinsic are defined
 187 // in library_call.cpp.
 188 
 189 
 190 #ifndef PRODUCT
 191 // statistics gathering...
 192 
 193 juint  Compile::_intrinsic_hist_count[vmIntrinsics::ID_LIMIT] = {0};
 194 jubyte Compile::_intrinsic_hist_flags[vmIntrinsics::ID_LIMIT] = {0};
 195 
 196 bool Compile::gather_intrinsic_statistics(vmIntrinsics::ID id, bool is_virtual, int flags) {
 197   assert(id > vmIntrinsics::_none && id < vmIntrinsics::ID_LIMIT, "oob");
 198   int oflags = _intrinsic_hist_flags[id];
 199   assert(flags != 0, "what happened?");
 200   if (is_virtual) {
 201     flags |= _intrinsic_virtual;
 202   }
 203   bool changed = (flags != oflags);
 204   if ((flags & _intrinsic_worked) != 0) {
 205     juint count = (_intrinsic_hist_count[id] += 1);
 206     if (count == 1) {
 207       changed = true;           // first time
 208     }
 209     // increment the overall count also:
 210     _intrinsic_hist_count[vmIntrinsics::_none] += 1;
 211   }
 212   if (changed) {
 213     if (((oflags ^ flags) & _intrinsic_virtual) != 0) {
 214       // Something changed about the intrinsic's virtuality.
 215       if ((flags & _intrinsic_virtual) != 0) {
 216         // This is the first use of this intrinsic as a virtual call.
 217         if (oflags != 0) {
 218           // We already saw it as a non-virtual, so note both cases.
 219           flags |= _intrinsic_both;
 220         }
 221       } else if ((oflags & _intrinsic_both) == 0) {
 222         // This is the first use of this intrinsic as a non-virtual
 223         flags |= _intrinsic_both;
 224       }
 225     }
 226     _intrinsic_hist_flags[id] = (jubyte) (oflags | flags);
 227   }
 228   // update the overall flags also:
 229   _intrinsic_hist_flags[vmIntrinsics::_none] |= (jubyte) flags;
 230   return changed;
 231 }
 232 
 233 static char* format_flags(int flags, char* buf) {
 234   buf[0] = 0;
 235   if ((flags & Compile::_intrinsic_worked) != 0)    strcat(buf, ",worked");
 236   if ((flags & Compile::_intrinsic_failed) != 0)    strcat(buf, ",failed");
 237   if ((flags & Compile::_intrinsic_disabled) != 0)  strcat(buf, ",disabled");
 238   if ((flags & Compile::_intrinsic_virtual) != 0)   strcat(buf, ",virtual");
 239   if ((flags & Compile::_intrinsic_both) != 0)      strcat(buf, ",nonvirtual");
 240   if (buf[0] == 0)  strcat(buf, ",");
 241   assert(buf[0] == ',', "must be");
 242   return &buf[1];
 243 }
 244 
 245 void Compile::print_intrinsic_statistics() {
 246   char flagsbuf[100];
 247   ttyLocker ttyl;
 248   if (xtty != NULL)  xtty->head("statistics type='intrinsic'");
 249   tty->print_cr("Compiler intrinsic usage:");
 250   juint total = _intrinsic_hist_count[vmIntrinsics::_none];
 251   if (total == 0)  total = 1;  // avoid div0 in case of no successes
 252   #define PRINT_STAT_LINE(name, c, f) \
 253     tty->print_cr("  %4d (%4.1f%%) %s (%s)", (int)(c), ((c) * 100.0) / total, name, f);
 254   for (int index = 1 + (int)vmIntrinsics::_none; index < (int)vmIntrinsics::ID_LIMIT; index++) {
 255     vmIntrinsics::ID id = (vmIntrinsics::ID) index;
 256     int   flags = _intrinsic_hist_flags[id];
 257     juint count = _intrinsic_hist_count[id];
 258     if ((flags | count) != 0) {
 259       PRINT_STAT_LINE(vmIntrinsics::name_at(id), count, format_flags(flags, flagsbuf));
 260     }
 261   }
 262   PRINT_STAT_LINE("total", total, format_flags(_intrinsic_hist_flags[vmIntrinsics::_none], flagsbuf));
 263   if (xtty != NULL)  xtty->tail("statistics");
 264 }
 265 
 266 void Compile::print_statistics() {
 267   { ttyLocker ttyl;
 268     if (xtty != NULL)  xtty->head("statistics type='opto'");
 269     Parse::print_statistics();
 270     PhaseCCP::print_statistics();
 271     PhaseRegAlloc::print_statistics();
 272     Scheduling::print_statistics();
 273     PhasePeephole::print_statistics();
 274     PhaseIdealLoop::print_statistics();
 275     if (xtty != NULL)  xtty->tail("statistics");
 276   }
 277   if (_intrinsic_hist_flags[vmIntrinsics::_none] != 0) {
 278     // put this under its own <statistics> element.
 279     print_intrinsic_statistics();
 280   }
 281 }
 282 #endif //PRODUCT
 283 
 284 // Support for bundling info
 285 Bundle* Compile::node_bundling(const Node *n) {
 286   assert(valid_bundle_info(n), "oob");
 287   return &_node_bundling_base[n->_idx];
 288 }
 289 
 290 bool Compile::valid_bundle_info(const Node *n) {
 291   return (_node_bundling_limit > n->_idx);
 292 }
 293 
 294 
 295 void Compile::gvn_replace_by(Node* n, Node* nn) {
 296   for (DUIterator_Last imin, i = n->last_outs(imin); i >= imin; ) {
 297     Node* use = n->last_out(i);
 298     bool is_in_table = initial_gvn()->hash_delete(use);
 299     uint uses_found = 0;
 300     for (uint j = 0; j < use->len(); j++) {
 301       if (use->in(j) == n) {
 302         if (j < use->req())
 303           use->set_req(j, nn);
 304         else
 305           use->set_prec(j, nn);
 306         uses_found++;
 307       }
 308     }
 309     if (is_in_table) {
 310       // reinsert into table
 311       initial_gvn()->hash_find_insert(use);
 312     }
 313     record_for_igvn(use);
 314     i -= uses_found;    // we deleted 1 or more copies of this edge
 315   }
 316 }
 317 
 318 
 319 static inline bool not_a_node(const Node* n) {
 320   if (n == NULL)                   return true;
 321   if (((intptr_t)n & 1) != 0)      return true;  // uninitialized, etc.
 322   if (*(address*)n == badAddress)  return true;  // kill by Node::destruct
 323   return false;
 324 }
 325 
 326 // Identify all nodes that are reachable from below, useful.
 327 // Use breadth-first pass that records state in a Unique_Node_List,
 328 // recursive traversal is slower.
 329 void Compile::identify_useful_nodes(Unique_Node_List &useful) {
 330   int estimated_worklist_size = live_nodes();
 331   useful.map( estimated_worklist_size, NULL );  // preallocate space
 332 
 333   // Initialize worklist
 334   if (root() != NULL)     { useful.push(root()); }
 335   // If 'top' is cached, declare it useful to preserve cached node
 336   if( cached_top_node() ) { useful.push(cached_top_node()); }
 337 
 338   // Push all useful nodes onto the list, breadthfirst
 339   for( uint next = 0; next < useful.size(); ++next ) {
 340     assert( next < unique(), "Unique useful nodes < total nodes");
 341     Node *n  = useful.at(next);
 342     uint max = n->len();
 343     for( uint i = 0; i < max; ++i ) {
 344       Node *m = n->in(i);
 345       if (not_a_node(m))  continue;
 346       useful.push(m);
 347     }
 348   }
 349 }
 350 
 351 // Update dead_node_list with any missing dead nodes using useful
 352 // list. Consider all non-useful nodes to be useless i.e., dead nodes.
 353 void Compile::update_dead_node_list(Unique_Node_List &useful) {
 354   uint max_idx = unique();
 355   VectorSet& useful_node_set = useful.member_set();
 356 
 357   for (uint node_idx = 0; node_idx < max_idx; node_idx++) {
 358     // If node with index node_idx is not in useful set,
 359     // mark it as dead in dead node list.
 360     if (! useful_node_set.test(node_idx) ) {
 361       record_dead_node(node_idx);
 362     }
 363   }
 364 }
 365 
 366 void Compile::remove_useless_late_inlines(GrowableArray<CallGenerator*>* inlines, Unique_Node_List &useful) {
 367   int shift = 0;
 368   for (int i = 0; i < inlines->length(); i++) {
 369     CallGenerator* cg = inlines->at(i);
 370     CallNode* call = cg->call_node();
 371     if (shift > 0) {
 372       inlines->at_put(i-shift, cg);
 373     }
 374     if (!useful.member(call)) {
 375       shift++;
 376     }
 377   }
 378   inlines->trunc_to(inlines->length()-shift);
 379 }
 380 
 381 // Disconnect all useless nodes by disconnecting those at the boundary.
 382 void Compile::remove_useless_nodes(Unique_Node_List &useful) {
 383   uint next = 0;
 384   while (next < useful.size()) {
 385     Node *n = useful.at(next++);
 386     if (n->is_SafePoint()) {
 387       // We're done with a parsing phase. Replaced nodes are not valid
 388       // beyond that point.
 389       n->as_SafePoint()->delete_replaced_nodes();
 390     }
 391     // Use raw traversal of out edges since this code removes out edges
 392     int max = n->outcnt();
 393     for (int j = 0; j < max; ++j) {
 394       Node* child = n->raw_out(j);
 395       if (! useful.member(child)) {
 396         assert(!child->is_top() || child != top(),
 397                "If top is cached in Compile object it is in useful list");
 398         // Only need to remove this out-edge to the useless node
 399         n->raw_del_out(j);
 400         --j;
 401         --max;
 402       }
 403     }
 404     if (n->outcnt() == 1 && n->has_special_unique_user()) {
 405       record_for_igvn(n->unique_out());
 406     }
 407   }
 408   // Remove useless macro and predicate opaq nodes
 409   for (int i = C->macro_count()-1; i >= 0; i--) {
 410     Node* n = C->macro_node(i);
 411     if (!useful.member(n)) {
 412       remove_macro_node(n);
 413     }
 414   }
 415   // Remove useless CastII nodes with range check dependency
 416   for (int i = range_check_cast_count() - 1; i >= 0; i--) {
 417     Node* cast = range_check_cast_node(i);
 418     if (!useful.member(cast)) {
 419       remove_range_check_cast(cast);
 420     }
 421   }
 422   // Remove useless expensive node
 423   for (int i = C->expensive_count()-1; i >= 0; i--) {
 424     Node* n = C->expensive_node(i);
 425     if (!useful.member(n)) {
 426       remove_expensive_node(n);
 427     }
 428   }
 429   // clean up the late inline lists
 430   remove_useless_late_inlines(&_string_late_inlines, useful);
 431   remove_useless_late_inlines(&_boxing_late_inlines, useful);
 432   remove_useless_late_inlines(&_late_inlines, useful);
 433   debug_only(verify_graph_edges(true/*check for no_dead_code*/);)
 434 }
 435 
 436 //------------------------------frame_size_in_words-----------------------------
 437 // frame_slots in units of words
 438 int Compile::frame_size_in_words() const {
 439   // shift is 0 in LP32 and 1 in LP64
 440   const int shift = (LogBytesPerWord - LogBytesPerInt);
 441   int words = _frame_slots >> shift;
 442   assert( words << shift == _frame_slots, "frame size must be properly aligned in LP64" );
 443   return words;
 444 }
 445 
 446 // To bang the stack of this compiled method we use the stack size
 447 // that the interpreter would need in case of a deoptimization. This
 448 // removes the need to bang the stack in the deoptimization blob which
 449 // in turn simplifies stack overflow handling.
 450 int Compile::bang_size_in_bytes() const {
 451   return MAX2(_interpreter_frame_size, frame_size_in_bytes());
 452 }
 453 
 454 // ============================================================================
 455 //------------------------------CompileWrapper---------------------------------
 456 class CompileWrapper : public StackObj {
 457   Compile *const _compile;
 458  public:
 459   CompileWrapper(Compile* compile);
 460 
 461   ~CompileWrapper();
 462 };
 463 
 464 CompileWrapper::CompileWrapper(Compile* compile) : _compile(compile) {
 465   // the Compile* pointer is stored in the current ciEnv:
 466   ciEnv* env = compile->env();
 467   assert(env == ciEnv::current(), "must already be a ciEnv active");
 468   assert(env->compiler_data() == NULL, "compile already active?");
 469   env->set_compiler_data(compile);
 470   assert(compile == Compile::current(), "sanity");
 471 
 472   compile->set_type_dict(NULL);
 473   compile->set_type_hwm(NULL);
 474   compile->set_type_last_size(0);
 475   compile->set_last_tf(NULL, NULL);
 476   compile->set_indexSet_arena(NULL);
 477   compile->set_indexSet_free_block_list(NULL);
 478   compile->init_type_arena();
 479   Type::Initialize(compile);
 480   _compile->set_scratch_buffer_blob(NULL);
 481   _compile->begin_method();
 482 }
 483 CompileWrapper::~CompileWrapper() {
 484   _compile->end_method();
 485   if (_compile->scratch_buffer_blob() != NULL)
 486     BufferBlob::free(_compile->scratch_buffer_blob());
 487   _compile->env()->set_compiler_data(NULL);
 488 }
 489 
 490 
 491 //----------------------------print_compile_messages---------------------------
 492 void Compile::print_compile_messages() {
 493 #ifndef PRODUCT
 494   // Check if recompiling
 495   if (_subsume_loads == false && PrintOpto) {
 496     // Recompiling without allowing machine instructions to subsume loads
 497     tty->print_cr("*********************************************************");
 498     tty->print_cr("** Bailout: Recompile without subsuming loads          **");
 499     tty->print_cr("*********************************************************");
 500   }
 501   if (_do_escape_analysis != DoEscapeAnalysis && PrintOpto) {
 502     // Recompiling without escape analysis
 503     tty->print_cr("*********************************************************");
 504     tty->print_cr("** Bailout: Recompile without escape analysis          **");
 505     tty->print_cr("*********************************************************");
 506   }
 507   if (_eliminate_boxing != EliminateAutoBox && PrintOpto) {
 508     // Recompiling without boxing elimination
 509     tty->print_cr("*********************************************************");
 510     tty->print_cr("** Bailout: Recompile without boxing elimination       **");
 511     tty->print_cr("*********************************************************");
 512   }
 513   if (env()->break_at_compile()) {
 514     // Open the debugger when compiling this method.
 515     tty->print("### Breaking when compiling: ");
 516     method()->print_short_name();
 517     tty->cr();
 518     BREAKPOINT;
 519   }
 520 
 521   if( PrintOpto ) {
 522     if (is_osr_compilation()) {
 523       tty->print("[OSR]%3d", _compile_id);
 524     } else {
 525       tty->print("%3d", _compile_id);
 526     }
 527   }
 528 #endif
 529 }
 530 
 531 
 532 //-----------------------init_scratch_buffer_blob------------------------------
 533 // Construct a temporary BufferBlob and cache it for this compile.
 534 void Compile::init_scratch_buffer_blob(int const_size) {
 535   // If there is already a scratch buffer blob allocated and the
 536   // constant section is big enough, use it.  Otherwise free the
 537   // current and allocate a new one.
 538   BufferBlob* blob = scratch_buffer_blob();
 539   if ((blob != NULL) && (const_size <= _scratch_const_size)) {
 540     // Use the current blob.
 541   } else {
 542     if (blob != NULL) {
 543       BufferBlob::free(blob);
 544     }
 545 
 546     ResourceMark rm;
 547     _scratch_const_size = const_size;
 548     int size = (MAX_inst_size + MAX_stubs_size + _scratch_const_size);
 549     blob = BufferBlob::create("Compile::scratch_buffer", size);
 550     // Record the buffer blob for next time.
 551     set_scratch_buffer_blob(blob);
 552     // Have we run out of code space?
 553     if (scratch_buffer_blob() == NULL) {
 554       // Let CompilerBroker disable further compilations.
 555       record_failure("Not enough space for scratch buffer in CodeCache");
 556       return;
 557     }
 558   }
 559 
 560   // Initialize the relocation buffers
 561   relocInfo* locs_buf = (relocInfo*) blob->content_end() - MAX_locs_size;
 562   set_scratch_locs_memory(locs_buf);
 563 }
 564 
 565 
 566 //-----------------------scratch_emit_size-------------------------------------
 567 // Helper function that computes size by emitting code
 568 uint Compile::scratch_emit_size(const Node* n) {
 569   // Start scratch_emit_size section.
 570   set_in_scratch_emit_size(true);
 571 
 572   // Emit into a trash buffer and count bytes emitted.
 573   // This is a pretty expensive way to compute a size,
 574   // but it works well enough if seldom used.
 575   // All common fixed-size instructions are given a size
 576   // method by the AD file.
 577   // Note that the scratch buffer blob and locs memory are
 578   // allocated at the beginning of the compile task, and
 579   // may be shared by several calls to scratch_emit_size.
 580   // The allocation of the scratch buffer blob is particularly
 581   // expensive, since it has to grab the code cache lock.
 582   BufferBlob* blob = this->scratch_buffer_blob();
 583   assert(blob != NULL, "Initialize BufferBlob at start");
 584   assert(blob->size() > MAX_inst_size, "sanity");
 585   relocInfo* locs_buf = scratch_locs_memory();
 586   address blob_begin = blob->content_begin();
 587   address blob_end   = (address)locs_buf;
 588   assert(blob->content_contains(blob_end), "sanity");
 589   CodeBuffer buf(blob_begin, blob_end - blob_begin);
 590   buf.initialize_consts_size(_scratch_const_size);
 591   buf.initialize_stubs_size(MAX_stubs_size);
 592   assert(locs_buf != NULL, "sanity");
 593   int lsize = MAX_locs_size / 3;
 594   buf.consts()->initialize_shared_locs(&locs_buf[lsize * 0], lsize);
 595   buf.insts()->initialize_shared_locs( &locs_buf[lsize * 1], lsize);
 596   buf.stubs()->initialize_shared_locs( &locs_buf[lsize * 2], lsize);
 597 
 598   // Do the emission.
 599 
 600   Label fakeL; // Fake label for branch instructions.
 601   Label*   saveL = NULL;
 602   uint save_bnum = 0;
 603   bool is_branch = n->is_MachBranch();
 604   if (is_branch) {
 605     MacroAssembler masm(&buf);
 606     masm.bind(fakeL);
 607     n->as_MachBranch()->save_label(&saveL, &save_bnum);
 608     n->as_MachBranch()->label_set(&fakeL, 0);
 609   }
 610   n->emit(buf, this->regalloc());
 611   if (is_branch) // Restore label.
 612     n->as_MachBranch()->label_set(saveL, save_bnum);
 613 
 614   // End scratch_emit_size section.
 615   set_in_scratch_emit_size(false);
 616 
 617   return buf.insts_size();
 618 }
 619 
 620 
 621 // ============================================================================
 622 //------------------------------Compile standard-------------------------------
 623 debug_only( int Compile::_debug_idx = 100000; )
 624 
 625 // Compile a method.  entry_bci is -1 for normal compilations and indicates
 626 // the continuation bci for on stack replacement.
 627 
 628 
 629 Compile::Compile( ciEnv* ci_env, C2Compiler* compiler, ciMethod* target, int osr_bci,
 630                   bool subsume_loads, bool do_escape_analysis, bool eliminate_boxing )
 631                 : Phase(Compiler),
 632                   _env(ci_env),
 633                   _log(ci_env->log()),
 634                   _compile_id(ci_env->compile_id()),
 635                   _save_argument_registers(false),
 636                   _stub_name(NULL),
 637                   _stub_function(NULL),
 638                   _stub_entry_point(NULL),
 639                   _method(target),
 640                   _entry_bci(osr_bci),
 641                   _initial_gvn(NULL),
 642                   _for_igvn(NULL),
 643                   _warm_calls(NULL),
 644                   _subsume_loads(subsume_loads),
 645                   _do_escape_analysis(do_escape_analysis),
 646                   _eliminate_boxing(eliminate_boxing),
 647                   _failure_reason(NULL),
 648                   _code_buffer("Compile::Fill_buffer"),
 649                   _orig_pc_slot(0),
 650                   _orig_pc_slot_offset_in_bytes(0),
 651                   _has_method_handle_invokes(false),
 652                   _mach_constant_base_node(NULL),
 653                   _node_bundling_limit(0),
 654                   _node_bundling_base(NULL),
 655                   _java_calls(0),
 656                   _inner_loops(0),
 657                   _scratch_const_size(-1),
 658                   _in_scratch_emit_size(false),
 659                   _dead_node_list(comp_arena()),
 660                   _dead_node_count(0),
 661 #ifndef PRODUCT
 662                   _trace_opto_output(TraceOptoOutput || method()->has_option("TraceOptoOutput")),
 663                   _in_dump_cnt(0),
 664                   _printer(IdealGraphPrinter::printer()),
 665 #endif
 666                   _congraph(NULL),
 667                   _comp_arena(mtCompiler),
 668                   _node_arena(mtCompiler),
 669                   _old_arena(mtCompiler),
 670                   _Compile_types(mtCompiler),
 671                   _replay_inline_data(NULL),
 672                   _late_inlines(comp_arena(), 2, 0, NULL),
 673                   _string_late_inlines(comp_arena(), 2, 0, NULL),
 674                   _boxing_late_inlines(comp_arena(), 2, 0, NULL),
 675                   _late_inlines_pos(0),
 676                   _number_of_mh_late_inlines(0),
 677                   _inlining_progress(false),
 678                   _inlining_incrementally(false),
 679                   _print_inlining_list(NULL),
 680                   _print_inlining_idx(0),
 681                   _interpreter_frame_size(0),
 682                   _max_node_limit(MaxNodeLimit) {
 683   C = this;
 684 
 685   CompileWrapper cw(this);
 686 #ifndef PRODUCT
 687   if (TimeCompiler2) {
 688     tty->print(" ");
 689     target->holder()->name()->print();
 690     tty->print(".");
 691     target->print_short_name();
 692     tty->print("  ");
 693   }
 694   TraceTime t1("Total compilation time", &_t_totalCompilation, TimeCompiler, TimeCompiler2);
 695   TraceTime t2(NULL, &_t_methodCompilation, TimeCompiler, false);
 696   bool print_opto_assembly = PrintOptoAssembly || _method->has_option("PrintOptoAssembly");
 697   if (!print_opto_assembly) {
 698     bool print_assembly = (PrintAssembly || _method->should_print_assembly());
 699     if (print_assembly && !Disassembler::can_decode()) {
 700       tty->print_cr("PrintAssembly request changed to PrintOptoAssembly");
 701       print_opto_assembly = true;
 702     }
 703   }
 704   set_print_assembly(print_opto_assembly);
 705   set_parsed_irreducible_loop(false);
 706 
 707   if (method()->has_option("ReplayInline")) {
 708     _replay_inline_data = ciReplay::load_inline_data(method(), entry_bci(), ci_env->comp_level());
 709   }
 710 #endif
 711   set_print_inlining(PrintInlining || method()->has_option("PrintInlining") NOT_PRODUCT( || PrintOptoInlining));
 712   set_print_intrinsics(PrintIntrinsics || method()->has_option("PrintIntrinsics"));
 713   set_has_irreducible_loop(true); // conservative until build_loop_tree() reset it
 714 
 715   if (ProfileTraps RTM_OPT_ONLY( || UseRTMLocking )) {
 716     // Make sure the method being compiled gets its own MDO,
 717     // so we can at least track the decompile_count().
 718     // Need MDO to record RTM code generation state.
 719     method()->ensure_method_data();
 720   }
 721 
 722   Init(::AliasLevel);
 723 
 724 
 725   print_compile_messages();
 726 
 727   _ilt = InlineTree::build_inline_tree_root();
 728 
 729   // Even if NO memory addresses are used, MergeMem nodes must have at least 1 slice
 730   assert(num_alias_types() >= AliasIdxRaw, "");
 731 
 732 #define MINIMUM_NODE_HASH  1023
 733   // Node list that Iterative GVN will start with
 734   Unique_Node_List for_igvn(comp_arena());
 735   set_for_igvn(&for_igvn);
 736 
 737   // GVN that will be run immediately on new nodes
 738   uint estimated_size = method()->code_size()*4+64;
 739   estimated_size = (estimated_size < MINIMUM_NODE_HASH ? MINIMUM_NODE_HASH : estimated_size);
 740   PhaseGVN gvn(node_arena(), estimated_size);
 741   set_initial_gvn(&gvn);
 742 
 743   if (print_inlining() || print_intrinsics()) {
 744     _print_inlining_list = new (comp_arena())GrowableArray<PrintInliningBuffer>(comp_arena(), 1, 1, PrintInliningBuffer());
 745   }
 746   { // Scope for timing the parser
 747     TracePhase t3("parse", &_t_parser, true);
 748 
 749     // Put top into the hash table ASAP.
 750     initial_gvn()->transform_no_reclaim(top());
 751 
 752     // Set up tf(), start(), and find a CallGenerator.
 753     CallGenerator* cg = NULL;
 754     if (is_osr_compilation()) {
 755       const TypeTuple *domain = StartOSRNode::osr_domain();
 756       const TypeTuple *range = TypeTuple::make_range(method()->signature());
 757       init_tf(TypeFunc::make(domain, range));
 758       StartNode* s = new (this) StartOSRNode(root(), domain);
 759       initial_gvn()->set_type_bottom(s);
 760       init_start(s);
 761       cg = CallGenerator::for_osr(method(), entry_bci());
 762     } else {
 763       // Normal case.
 764       init_tf(TypeFunc::make(method()));
 765       StartNode* s = new (this) StartNode(root(), tf()->domain());
 766       initial_gvn()->set_type_bottom(s);
 767       init_start(s);
 768       if (method()->intrinsic_id() == vmIntrinsics::_Reference_get && UseG1GC) {
 769         // With java.lang.ref.reference.get() we must go through the
 770         // intrinsic when G1 is enabled - even when get() is the root
 771         // method of the compile - so that, if necessary, the value in
 772         // the referent field of the reference object gets recorded by
 773         // the pre-barrier code.
 774         // Specifically, if G1 is enabled, the value in the referent
 775         // field is recorded by the G1 SATB pre barrier. This will
 776         // result in the referent being marked live and the reference
 777         // object removed from the list of discovered references during
 778         // reference processing.
 779         cg = find_intrinsic(method(), false);
 780       }
 781       if (cg == NULL) {
 782         float past_uses = method()->interpreter_invocation_count();
 783         float expected_uses = past_uses;
 784         cg = CallGenerator::for_inline(method(), expected_uses);
 785       }
 786     }
 787     if (failing())  return;
 788     if (cg == NULL) {
 789       record_method_not_compilable_all_tiers("cannot parse method");
 790       return;
 791     }
 792     JVMState* jvms = build_start_state(start(), tf());
 793     if ((jvms = cg->generate(jvms)) == NULL) {
 794       record_method_not_compilable("method parse failed");
 795       return;
 796     }
 797     GraphKit kit(jvms);
 798 
 799     if (!kit.stopped()) {
 800       // Accept return values, and transfer control we know not where.
 801       // This is done by a special, unique ReturnNode bound to root.
 802       return_values(kit.jvms());
 803     }
 804 
 805     if (kit.has_exceptions()) {
 806       // Any exceptions that escape from this call must be rethrown
 807       // to whatever caller is dynamically above us on the stack.
 808       // This is done by a special, unique RethrowNode bound to root.
 809       rethrow_exceptions(kit.transfer_exceptions_into_jvms());
 810     }
 811 
 812     assert(IncrementalInline || (_late_inlines.length() == 0 && !has_mh_late_inlines()), "incremental inlining is off");
 813 
 814     if (_late_inlines.length() == 0 && !has_mh_late_inlines() && !failing() && has_stringbuilder()) {
 815       inline_string_calls(true);
 816     }
 817 
 818     if (failing())  return;
 819 
 820     print_method(PHASE_BEFORE_REMOVEUSELESS, 3);
 821 
 822     // Remove clutter produced by parsing.
 823     if (!failing()) {
 824       ResourceMark rm;
 825       PhaseRemoveUseless pru(initial_gvn(), &for_igvn);
 826     }
 827   }
 828 
 829   // Note:  Large methods are capped off in do_one_bytecode().
 830   if (failing())  return;
 831 
 832   // After parsing, node notes are no longer automagic.
 833   // They must be propagated by register_new_node_with_optimizer(),
 834   // clone(), or the like.
 835   set_default_node_notes(NULL);
 836 
 837   for (;;) {
 838     int successes = Inline_Warm();
 839     if (failing())  return;
 840     if (successes == 0)  break;
 841   }
 842 
 843   // Drain the list.
 844   Finish_Warm();
 845 #ifndef PRODUCT
 846   if (_printer) {
 847     _printer->print_inlining(this);
 848   }
 849 #endif
 850 
 851   if (failing())  return;
 852   NOT_PRODUCT( verify_graph_edges(); )
 853 
 854   // Now optimize
 855   Optimize();
 856   if (failing())  return;
 857   NOT_PRODUCT( verify_graph_edges(); )
 858 
 859 #ifndef PRODUCT
 860   if (PrintIdeal) {
 861     ttyLocker ttyl;  // keep the following output all in one block
 862     // This output goes directly to the tty, not the compiler log.
 863     // To enable tools to match it up with the compilation activity,
 864     // be sure to tag this tty output with the compile ID.
 865     if (xtty != NULL) {
 866       xtty->head("ideal compile_id='%d'%s", compile_id(),
 867                  is_osr_compilation()    ? " compile_kind='osr'" :
 868                  "");
 869     }
 870     root()->dump(9999);
 871     if (xtty != NULL) {
 872       xtty->tail("ideal");
 873     }
 874   }
 875 #endif
 876 
 877   NOT_PRODUCT( verify_barriers(); )
 878 
 879   // Dump compilation data to replay it.
 880   if (method()->has_option("DumpReplay")) {
 881     env()->dump_replay_data(_compile_id);
 882   }
 883   if (method()->has_option("DumpInline") && (ilt() != NULL)) {
 884     env()->dump_inline_data(_compile_id);
 885   }
 886 
 887   // Now that we know the size of all the monitors we can add a fixed slot
 888   // for the original deopt pc.
 889 
 890   _orig_pc_slot =  fixed_slots();
 891   int next_slot = _orig_pc_slot + (sizeof(address) / VMRegImpl::stack_slot_size);
 892   set_fixed_slots(next_slot);
 893 
 894   // Compute when to use implicit null checks. Used by matching trap based
 895   // nodes and NullCheck optimization.
 896   set_allowed_deopt_reasons();
 897 
 898   // Now generate code
 899   Code_Gen();
 900   if (failing())  return;
 901 
 902   // Check if we want to skip execution of all compiled code.
 903   {
 904 #ifndef PRODUCT
 905     if (OptoNoExecute) {
 906       record_method_not_compilable("+OptoNoExecute");  // Flag as failed
 907       return;
 908     }
 909     TracePhase t2("install_code", &_t_registerMethod, TimeCompiler);
 910 #endif
 911 
 912     if (is_osr_compilation()) {
 913       _code_offsets.set_value(CodeOffsets::Verified_Entry, 0);
 914       _code_offsets.set_value(CodeOffsets::OSR_Entry, _first_block_size);
 915     } else {
 916       _code_offsets.set_value(CodeOffsets::Verified_Entry, _first_block_size);
 917       _code_offsets.set_value(CodeOffsets::OSR_Entry, 0);
 918     }
 919 
 920     env()->register_method(_method, _entry_bci,
 921                            &_code_offsets,
 922                            _orig_pc_slot_offset_in_bytes,
 923                            code_buffer(),
 924                            frame_size_in_words(), _oop_map_set,
 925                            &_handler_table, &_inc_table,
 926                            compiler,
 927                            env()->comp_level(),
 928                            has_unsafe_access(),
 929                            SharedRuntime::is_wide_vector(max_vector_size()),
 930                            rtm_state()
 931                            );
 932 
 933     if (log() != NULL) // Print code cache state into compiler log
 934       log()->code_cache_state();
 935   }
 936 }
 937 
 938 //------------------------------Compile----------------------------------------
 939 // Compile a runtime stub
 940 Compile::Compile( ciEnv* ci_env,
 941                   TypeFunc_generator generator,
 942                   address stub_function,
 943                   const char *stub_name,
 944                   int is_fancy_jump,
 945                   bool pass_tls,
 946                   bool save_arg_registers,
 947                   bool return_pc )
 948   : Phase(Compiler),
 949     _env(ci_env),
 950     _log(ci_env->log()),
 951     _compile_id(0),
 952     _save_argument_registers(save_arg_registers),
 953     _method(NULL),
 954     _stub_name(stub_name),
 955     _stub_function(stub_function),
 956     _stub_entry_point(NULL),
 957     _entry_bci(InvocationEntryBci),
 958     _initial_gvn(NULL),
 959     _for_igvn(NULL),
 960     _warm_calls(NULL),
 961     _orig_pc_slot(0),
 962     _orig_pc_slot_offset_in_bytes(0),
 963     _subsume_loads(true),
 964     _do_escape_analysis(false),
 965     _eliminate_boxing(false),
 966     _failure_reason(NULL),
 967     _code_buffer("Compile::Fill_buffer"),
 968     _has_method_handle_invokes(false),
 969     _mach_constant_base_node(NULL),
 970     _node_bundling_limit(0),
 971     _node_bundling_base(NULL),
 972     _java_calls(0),
 973     _inner_loops(0),
 974 #ifndef PRODUCT
 975     _trace_opto_output(TraceOptoOutput),
 976     _in_dump_cnt(0),
 977     _printer(NULL),
 978 #endif
 979     _comp_arena(mtCompiler),
 980     _node_arena(mtCompiler),
 981     _old_arena(mtCompiler),
 982     _Compile_types(mtCompiler),
 983     _dead_node_list(comp_arena()),
 984     _dead_node_count(0),
 985     _congraph(NULL),
 986     _replay_inline_data(NULL),
 987     _number_of_mh_late_inlines(0),
 988     _inlining_progress(false),
 989     _inlining_incrementally(false),
 990     _print_inlining_list(NULL),
 991     _print_inlining_idx(0),
 992     _allowed_reasons(0),
 993     _interpreter_frame_size(0),
 994     _max_node_limit(MaxNodeLimit) {
 995   C = this;
 996 
 997 #ifndef PRODUCT
 998   TraceTime t1(NULL, &_t_totalCompilation, TimeCompiler, false);
 999   TraceTime t2(NULL, &_t_stubCompilation, TimeCompiler, false);
1000   set_print_assembly(PrintFrameConverterAssembly);
1001   set_parsed_irreducible_loop(false);
1002 #endif
1003   set_has_irreducible_loop(false); // no loops
1004 
1005   CompileWrapper cw(this);
1006   Init(/*AliasLevel=*/ 0);
1007   init_tf((*generator)());
1008 
1009   {
1010     // The following is a dummy for the sake of GraphKit::gen_stub
1011     Unique_Node_List for_igvn(comp_arena());
1012     set_for_igvn(&for_igvn);  // not used, but some GraphKit guys push on this
1013     PhaseGVN gvn(Thread::current()->resource_area(),255);
1014     set_initial_gvn(&gvn);    // not significant, but GraphKit guys use it pervasively
1015     gvn.transform_no_reclaim(top());
1016 
1017     GraphKit kit;
1018     kit.gen_stub(stub_function, stub_name, is_fancy_jump, pass_tls, return_pc);
1019   }
1020 
1021   NOT_PRODUCT( verify_graph_edges(); )
1022   Code_Gen();
1023   if (failing())  return;
1024 
1025 
1026   // Entry point will be accessed using compile->stub_entry_point();
1027   if (code_buffer() == NULL) {
1028     Matcher::soft_match_failure();
1029   } else {
1030     if (PrintAssembly && (WizardMode || Verbose))
1031       tty->print_cr("### Stub::%s", stub_name);
1032 
1033     if (!failing()) {
1034       assert(_fixed_slots == 0, "no fixed slots used for runtime stubs");
1035 
1036       // Make the NMethod
1037       // For now we mark the frame as never safe for profile stackwalking
1038       RuntimeStub *rs = RuntimeStub::new_runtime_stub(stub_name,
1039                                                       code_buffer(),
1040                                                       CodeOffsets::frame_never_safe,
1041                                                       // _code_offsets.value(CodeOffsets::Frame_Complete),
1042                                                       frame_size_in_words(),
1043                                                       _oop_map_set,
1044                                                       save_arg_registers);
1045       assert(rs != NULL && rs->is_runtime_stub(), "sanity check");
1046 
1047       _stub_entry_point = rs->entry_point();
1048     }
1049   }
1050 }
1051 
1052 //------------------------------Init-------------------------------------------
1053 // Prepare for a single compilation
1054 void Compile::Init(int aliaslevel) {
1055   _unique  = 0;
1056   _regalloc = NULL;
1057 
1058   _tf      = NULL;  // filled in later
1059   _top     = NULL;  // cached later
1060   _matcher = NULL;  // filled in later
1061   _cfg     = NULL;  // filled in later
1062 
1063   set_24_bit_selection_and_mode(Use24BitFP, false);
1064 
1065   _node_note_array = NULL;
1066   _default_node_notes = NULL;
1067 
1068   _immutable_memory = NULL; // filled in at first inquiry
1069 
1070   // Globally visible Nodes
1071   // First set TOP to NULL to give safe behavior during creation of RootNode
1072   set_cached_top_node(NULL);
1073   set_root(new (this) RootNode());
1074   // Now that you have a Root to point to, create the real TOP
1075   set_cached_top_node( new (this) ConNode(Type::TOP) );
1076   set_recent_alloc(NULL, NULL);
1077 
1078   // Create Debug Information Recorder to record scopes, oopmaps, etc.
1079   env()->set_oop_recorder(new OopRecorder(env()->arena()));
1080   env()->set_debug_info(new DebugInformationRecorder(env()->oop_recorder()));
1081   env()->set_dependencies(new Dependencies(env()));
1082 
1083   _fixed_slots = 0;
1084   set_has_split_ifs(false);
1085   set_has_loops(has_method() && method()->has_loops()); // first approximation
1086   set_has_stringbuilder(false);
1087   set_has_boxed_value(false);
1088   _trap_can_recompile = false;  // no traps emitted yet
1089   _major_progress = true; // start out assuming good things will happen
1090   set_has_unsafe_access(false);
1091   set_max_vector_size(0);
1092   Copy::zero_to_bytes(_trap_hist, sizeof(_trap_hist));
1093   set_decompile_count(0);
1094 
1095   set_do_freq_based_layout(BlockLayoutByFrequency || method_has_option("BlockLayoutByFrequency"));
1096   set_num_loop_opts(LoopOptsCount);
1097   set_do_inlining(Inline);
1098   set_max_inline_size(MaxInlineSize);
1099   set_freq_inline_size(FreqInlineSize);
1100   set_do_scheduling(OptoScheduling);
1101   set_do_count_invocations(false);
1102   set_do_method_data_update(false);
1103   set_rtm_state(NoRTM); // No RTM lock eliding by default
1104   method_has_option_value("MaxNodeLimit", _max_node_limit);
1105 #if INCLUDE_RTM_OPT
1106   if (UseRTMLocking && has_method() && (method()->method_data_or_null() != NULL)) {
1107     int rtm_state = method()->method_data()->rtm_state();
1108     if (method_has_option("NoRTMLockEliding") || ((rtm_state & NoRTM) != 0)) {
1109       // Don't generate RTM lock eliding code.
1110       set_rtm_state(NoRTM);
1111     } else if (method_has_option("UseRTMLockEliding") || ((rtm_state & UseRTM) != 0) || !UseRTMDeopt) {
1112       // Generate RTM lock eliding code without abort ratio calculation code.
1113       set_rtm_state(UseRTM);
1114     } else if (UseRTMDeopt) {
1115       // Generate RTM lock eliding code and include abort ratio calculation
1116       // code if UseRTMDeopt is on.
1117       set_rtm_state(ProfileRTM);
1118     }
1119   }
1120 #endif
1121   if (debug_info()->recording_non_safepoints()) {
1122     set_node_note_array(new(comp_arena()) GrowableArray<Node_Notes*>
1123                         (comp_arena(), 8, 0, NULL));
1124     set_default_node_notes(Node_Notes::make(this));
1125   }
1126 
1127   // // -- Initialize types before each compile --
1128   // // Update cached type information
1129   // if( _method && _method->constants() )
1130   //   Type::update_loaded_types(_method, _method->constants());
1131 
1132   // Init alias_type map.
1133   if (!_do_escape_analysis && aliaslevel == 3)
1134     aliaslevel = 2;  // No unique types without escape analysis
1135   _AliasLevel = aliaslevel;
1136   const int grow_ats = 16;
1137   _max_alias_types = grow_ats;
1138   _alias_types   = NEW_ARENA_ARRAY(comp_arena(), AliasType*, grow_ats);
1139   AliasType* ats = NEW_ARENA_ARRAY(comp_arena(), AliasType,  grow_ats);
1140   Copy::zero_to_bytes(ats, sizeof(AliasType)*grow_ats);
1141   {
1142     for (int i = 0; i < grow_ats; i++)  _alias_types[i] = &ats[i];
1143   }
1144   // Initialize the first few types.
1145   _alias_types[AliasIdxTop]->Init(AliasIdxTop, NULL);
1146   _alias_types[AliasIdxBot]->Init(AliasIdxBot, TypePtr::BOTTOM);
1147   _alias_types[AliasIdxRaw]->Init(AliasIdxRaw, TypeRawPtr::BOTTOM);
1148   _num_alias_types = AliasIdxRaw+1;
1149   // Zero out the alias type cache.
1150   Copy::zero_to_bytes(_alias_cache, sizeof(_alias_cache));
1151   // A NULL adr_type hits in the cache right away.  Preload the right answer.
1152   probe_alias_cache(NULL)->_index = AliasIdxTop;
1153 
1154   _intrinsics = NULL;
1155   _macro_nodes = new(comp_arena()) GrowableArray<Node*>(comp_arena(), 8,  0, NULL);
1156   _predicate_opaqs = new(comp_arena()) GrowableArray<Node*>(comp_arena(), 8,  0, NULL);
1157   _expensive_nodes = new(comp_arena()) GrowableArray<Node*>(comp_arena(), 8,  0, NULL);
1158   _range_check_casts = new(comp_arena()) GrowableArray<Node*>(comp_arena(), 8,  0, NULL);
1159   register_library_intrinsics();
1160 }
1161 
1162 //---------------------------init_start----------------------------------------
1163 // Install the StartNode on this compile object.
1164 void Compile::init_start(StartNode* s) {
1165   if (failing())
1166     return; // already failing
1167   assert(s == start(), "");
1168 }
1169 
1170 StartNode* Compile::start() const {
1171   assert(!failing(), "");
1172   for (DUIterator_Fast imax, i = root()->fast_outs(imax); i < imax; i++) {
1173     Node* start = root()->fast_out(i);
1174     if( start->is_Start() )
1175       return start->as_Start();
1176   }
1177   fatal("Did not find Start node!");
1178   return NULL;
1179 }
1180 
1181 //-------------------------------immutable_memory-------------------------------------
1182 // Access immutable memory
1183 Node* Compile::immutable_memory() {
1184   if (_immutable_memory != NULL) {
1185     return _immutable_memory;
1186   }
1187   StartNode* s = start();
1188   for (DUIterator_Fast imax, i = s->fast_outs(imax); true; i++) {
1189     Node *p = s->fast_out(i);
1190     if (p != s && p->as_Proj()->_con == TypeFunc::Memory) {
1191       _immutable_memory = p;
1192       return _immutable_memory;
1193     }
1194   }
1195   ShouldNotReachHere();
1196   return NULL;
1197 }
1198 
1199 //----------------------set_cached_top_node------------------------------------
1200 // Install the cached top node, and make sure Node::is_top works correctly.
1201 void Compile::set_cached_top_node(Node* tn) {
1202   if (tn != NULL)  verify_top(tn);
1203   Node* old_top = _top;
1204   _top = tn;
1205   // Calling Node::setup_is_top allows the nodes the chance to adjust
1206   // their _out arrays.
1207   if (_top != NULL)     _top->setup_is_top();
1208   if (old_top != NULL)  old_top->setup_is_top();
1209   assert(_top == NULL || top()->is_top(), "");
1210 }
1211 
1212 #ifdef ASSERT
1213 uint Compile::count_live_nodes_by_graph_walk() {
1214   Unique_Node_List useful(comp_arena());
1215   // Get useful node list by walking the graph.
1216   identify_useful_nodes(useful);
1217   return useful.size();
1218 }
1219 
1220 void Compile::print_missing_nodes() {
1221 
1222   // Return if CompileLog is NULL and PrintIdealNodeCount is false.
1223   if ((_log == NULL) && (! PrintIdealNodeCount)) {
1224     return;
1225   }
1226 
1227   // This is an expensive function. It is executed only when the user
1228   // specifies VerifyIdealNodeCount option or otherwise knows the
1229   // additional work that needs to be done to identify reachable nodes
1230   // by walking the flow graph and find the missing ones using
1231   // _dead_node_list.
1232 
1233   Unique_Node_List useful(comp_arena());
1234   // Get useful node list by walking the graph.
1235   identify_useful_nodes(useful);
1236 
1237   uint l_nodes = C->live_nodes();
1238   uint l_nodes_by_walk = useful.size();
1239 
1240   if (l_nodes != l_nodes_by_walk) {
1241     if (_log != NULL) {
1242       _log->begin_head("mismatched_nodes count='%d'", abs((int) (l_nodes - l_nodes_by_walk)));
1243       _log->stamp();
1244       _log->end_head();
1245     }
1246     VectorSet& useful_member_set = useful.member_set();
1247     int last_idx = l_nodes_by_walk;
1248     for (int i = 0; i < last_idx; i++) {
1249       if (useful_member_set.test(i)) {
1250         if (_dead_node_list.test(i)) {
1251           if (_log != NULL) {
1252             _log->elem("mismatched_node_info node_idx='%d' type='both live and dead'", i);
1253           }
1254           if (PrintIdealNodeCount) {
1255             // Print the log message to tty
1256               tty->print_cr("mismatched_node idx='%d' both live and dead'", i);
1257               useful.at(i)->dump();
1258           }
1259         }
1260       }
1261       else if (! _dead_node_list.test(i)) {
1262         if (_log != NULL) {
1263           _log->elem("mismatched_node_info node_idx='%d' type='neither live nor dead'", i);
1264         }
1265         if (PrintIdealNodeCount) {
1266           // Print the log message to tty
1267           tty->print_cr("mismatched_node idx='%d' type='neither live nor dead'", i);
1268         }
1269       }
1270     }
1271     if (_log != NULL) {
1272       _log->tail("mismatched_nodes");
1273     }
1274   }
1275 }
1276 #endif
1277 
1278 #ifndef PRODUCT
1279 void Compile::verify_top(Node* tn) const {
1280   if (tn != NULL) {
1281     assert(tn->is_Con(), "top node must be a constant");
1282     assert(((ConNode*)tn)->type() == Type::TOP, "top node must have correct type");
1283     assert(tn->in(0) != NULL, "must have live top node");
1284   }
1285 }
1286 #endif
1287 
1288 
1289 ///-------------------Managing Per-Node Debug & Profile Info-------------------
1290 
1291 void Compile::grow_node_notes(GrowableArray<Node_Notes*>* arr, int grow_by) {
1292   guarantee(arr != NULL, "");
1293   int num_blocks = arr->length();
1294   if (grow_by < num_blocks)  grow_by = num_blocks;
1295   int num_notes = grow_by * _node_notes_block_size;
1296   Node_Notes* notes = NEW_ARENA_ARRAY(node_arena(), Node_Notes, num_notes);
1297   Copy::zero_to_bytes(notes, num_notes * sizeof(Node_Notes));
1298   while (num_notes > 0) {
1299     arr->append(notes);
1300     notes     += _node_notes_block_size;
1301     num_notes -= _node_notes_block_size;
1302   }
1303   assert(num_notes == 0, "exact multiple, please");
1304 }
1305 
1306 bool Compile::copy_node_notes_to(Node* dest, Node* source) {
1307   if (source == NULL || dest == NULL)  return false;
1308 
1309   if (dest->is_Con())
1310     return false;               // Do not push debug info onto constants.
1311 
1312 #ifdef ASSERT
1313   // Leave a bread crumb trail pointing to the original node:
1314   if (dest != NULL && dest != source && dest->debug_orig() == NULL) {
1315     dest->set_debug_orig(source);
1316   }
1317 #endif
1318 
1319   if (node_note_array() == NULL)
1320     return false;               // Not collecting any notes now.
1321 
1322   // This is a copy onto a pre-existing node, which may already have notes.
1323   // If both nodes have notes, do not overwrite any pre-existing notes.
1324   Node_Notes* source_notes = node_notes_at(source->_idx);
1325   if (source_notes == NULL || source_notes->is_clear())  return false;
1326   Node_Notes* dest_notes   = node_notes_at(dest->_idx);
1327   if (dest_notes == NULL || dest_notes->is_clear()) {
1328     return set_node_notes_at(dest->_idx, source_notes);
1329   }
1330 
1331   Node_Notes merged_notes = (*source_notes);
1332   // The order of operations here ensures that dest notes will win...
1333   merged_notes.update_from(dest_notes);
1334   return set_node_notes_at(dest->_idx, &merged_notes);
1335 }
1336 
1337 
1338 //--------------------------allow_range_check_smearing-------------------------
1339 // Gating condition for coalescing similar range checks.
1340 // Sometimes we try 'speculatively' replacing a series of a range checks by a
1341 // single covering check that is at least as strong as any of them.
1342 // If the optimization succeeds, the simplified (strengthened) range check
1343 // will always succeed.  If it fails, we will deopt, and then give up
1344 // on the optimization.
1345 bool Compile::allow_range_check_smearing() const {
1346   // If this method has already thrown a range-check,
1347   // assume it was because we already tried range smearing
1348   // and it failed.
1349   uint already_trapped = trap_count(Deoptimization::Reason_range_check);
1350   return !already_trapped;
1351 }
1352 
1353 
1354 //------------------------------flatten_alias_type-----------------------------
1355 const TypePtr *Compile::flatten_alias_type( const TypePtr *tj ) const {
1356   int offset = tj->offset();
1357   TypePtr::PTR ptr = tj->ptr();
1358 
1359   // Known instance (scalarizable allocation) alias only with itself.
1360   bool is_known_inst = tj->isa_oopptr() != NULL &&
1361                        tj->is_oopptr()->is_known_instance();
1362 
1363   // Process weird unsafe references.
1364   if (offset == Type::OffsetBot && (tj->isa_instptr() /*|| tj->isa_klassptr()*/)) {
1365     assert(InlineUnsafeOps, "indeterminate pointers come only from unsafe ops");
1366     assert(!is_known_inst, "scalarizable allocation should not have unsafe references");
1367     tj = TypeOopPtr::BOTTOM;
1368     ptr = tj->ptr();
1369     offset = tj->offset();
1370   }
1371 
1372   // Array pointers need some flattening
1373   const TypeAryPtr *ta = tj->isa_aryptr();
1374   if (ta && ta->is_stable()) {
1375     // Erase stability property for alias analysis.
1376     tj = ta = ta->cast_to_stable(false);
1377   }
1378   if( ta && is_known_inst ) {
1379     if ( offset != Type::OffsetBot &&
1380          offset > arrayOopDesc::length_offset_in_bytes() ) {
1381       offset = Type::OffsetBot; // Flatten constant access into array body only
1382       tj = ta = TypeAryPtr::make(ptr, ta->ary(), ta->klass(), true, offset, ta->instance_id());
1383     }
1384   } else if( ta && _AliasLevel >= 2 ) {
1385     // For arrays indexed by constant indices, we flatten the alias
1386     // space to include all of the array body.  Only the header, klass
1387     // and array length can be accessed un-aliased.
1388     if( offset != Type::OffsetBot ) {
1389       if( ta->const_oop() ) { // MethodData* or Method*
1390         offset = Type::OffsetBot;   // Flatten constant access into array body
1391         tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),ta->ary(),ta->klass(),false,offset);
1392       } else if( offset == arrayOopDesc::length_offset_in_bytes() ) {
1393         // range is OK as-is.
1394         tj = ta = TypeAryPtr::RANGE;
1395       } else if( offset == oopDesc::klass_offset_in_bytes() ) {
1396         tj = TypeInstPtr::KLASS; // all klass loads look alike
1397         ta = TypeAryPtr::RANGE; // generic ignored junk
1398         ptr = TypePtr::BotPTR;
1399       } else if( offset == oopDesc::mark_offset_in_bytes() ) {
1400         tj = TypeInstPtr::MARK;
1401         ta = TypeAryPtr::RANGE; // generic ignored junk
1402         ptr = TypePtr::BotPTR;
1403       } else {                  // Random constant offset into array body
1404         offset = Type::OffsetBot;   // Flatten constant access into array body
1405         tj = ta = TypeAryPtr::make(ptr,ta->ary(),ta->klass(),false,offset);
1406       }
1407     }
1408     // Arrays of fixed size alias with arrays of unknown size.
1409     if (ta->size() != TypeInt::POS) {
1410       const TypeAry *tary = TypeAry::make(ta->elem(), TypeInt::POS);
1411       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,ta->klass(),false,offset);
1412     }
1413     // Arrays of known objects become arrays of unknown objects.
1414     if (ta->elem()->isa_narrowoop() && ta->elem() != TypeNarrowOop::BOTTOM) {
1415       const TypeAry *tary = TypeAry::make(TypeNarrowOop::BOTTOM, ta->size());
1416       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,NULL,false,offset);
1417     }
1418     if (ta->elem()->isa_oopptr() && ta->elem() != TypeInstPtr::BOTTOM) {
1419       const TypeAry *tary = TypeAry::make(TypeInstPtr::BOTTOM, ta->size());
1420       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,NULL,false,offset);
1421     }
1422     // Arrays of bytes and of booleans both use 'bastore' and 'baload' so
1423     // cannot be distinguished by bytecode alone.
1424     if (ta->elem() == TypeInt::BOOL) {
1425       const TypeAry *tary = TypeAry::make(TypeInt::BYTE, ta->size());
1426       ciKlass* aklass = ciTypeArrayKlass::make(T_BYTE);
1427       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,aklass,false,offset);
1428     }
1429     // During the 2nd round of IterGVN, NotNull castings are removed.
1430     // Make sure the Bottom and NotNull variants alias the same.
1431     // Also, make sure exact and non-exact variants alias the same.
1432     if (ptr == TypePtr::NotNull || ta->klass_is_exact() || ta->speculative() != NULL) {
1433       tj = ta = TypeAryPtr::make(TypePtr::BotPTR,ta->ary(),ta->klass(),false,offset);
1434     }
1435   }
1436 
1437   // Oop pointers need some flattening
1438   const TypeInstPtr *to = tj->isa_instptr();
1439   if( to && _AliasLevel >= 2 && to != TypeOopPtr::BOTTOM ) {
1440     ciInstanceKlass *k = to->klass()->as_instance_klass();
1441     if( ptr == TypePtr::Constant ) {
1442       if (to->klass() != ciEnv::current()->Class_klass() ||
1443           offset < k->size_helper() * wordSize) {
1444         // No constant oop pointers (such as Strings); they alias with
1445         // unknown strings.
1446         assert(!is_known_inst, "not scalarizable allocation");
1447         tj = to = TypeInstPtr::make(TypePtr::BotPTR,to->klass(),false,0,offset);
1448       }
1449     } else if( is_known_inst ) {
1450       tj = to; // Keep NotNull and klass_is_exact for instance type
1451     } else if( ptr == TypePtr::NotNull || to->klass_is_exact() ) {
1452       // During the 2nd round of IterGVN, NotNull castings are removed.
1453       // Make sure the Bottom and NotNull variants alias the same.
1454       // Also, make sure exact and non-exact variants alias the same.
1455       tj = to = TypeInstPtr::make(TypePtr::BotPTR,to->klass(),false,0,offset);
1456     }
1457     if (to->speculative() != NULL) {
1458       tj = to = TypeInstPtr::make(to->ptr(),to->klass(),to->klass_is_exact(),to->const_oop(),to->offset(), to->instance_id());
1459     }
1460     // Canonicalize the holder of this field
1461     if (offset >= 0 && offset < instanceOopDesc::base_offset_in_bytes()) {
1462       // First handle header references such as a LoadKlassNode, even if the
1463       // object's klass is unloaded at compile time (4965979).
1464       if (!is_known_inst) { // Do it only for non-instance types
1465         tj = to = TypeInstPtr::make(TypePtr::BotPTR, env()->Object_klass(), false, NULL, offset);
1466       }
1467     } else if (offset < 0 || offset >= k->size_helper() * wordSize) {
1468       // Static fields are in the space above the normal instance
1469       // fields in the java.lang.Class instance.
1470       if (to->klass() != ciEnv::current()->Class_klass()) {
1471         to = NULL;
1472         tj = TypeOopPtr::BOTTOM;
1473         offset = tj->offset();
1474       }
1475     } else {
1476       ciInstanceKlass *canonical_holder = k->get_canonical_holder(offset);
1477       if (!k->equals(canonical_holder) || tj->offset() != offset) {
1478         if( is_known_inst ) {
1479           tj = to = TypeInstPtr::make(to->ptr(), canonical_holder, true, NULL, offset, to->instance_id());
1480         } else {
1481           tj = to = TypeInstPtr::make(to->ptr(), canonical_holder, false, NULL, offset);
1482         }
1483       }
1484     }
1485   }
1486 
1487   // Klass pointers to object array klasses need some flattening
1488   const TypeKlassPtr *tk = tj->isa_klassptr();
1489   if( tk ) {
1490     // If we are referencing a field within a Klass, we need
1491     // to assume the worst case of an Object.  Both exact and
1492     // inexact types must flatten to the same alias class so
1493     // use NotNull as the PTR.
1494     if ( offset == Type::OffsetBot || (offset >= 0 && (size_t)offset < sizeof(Klass)) ) {
1495 
1496       tj = tk = TypeKlassPtr::make(TypePtr::NotNull,
1497                                    TypeKlassPtr::OBJECT->klass(),
1498                                    offset);
1499     }
1500 
1501     ciKlass* klass = tk->klass();
1502     if( klass->is_obj_array_klass() ) {
1503       ciKlass* k = TypeAryPtr::OOPS->klass();
1504       if( !k || !k->is_loaded() )                  // Only fails for some -Xcomp runs
1505         k = TypeInstPtr::BOTTOM->klass();
1506       tj = tk = TypeKlassPtr::make( TypePtr::NotNull, k, offset );
1507     }
1508 
1509     // Check for precise loads from the primary supertype array and force them
1510     // to the supertype cache alias index.  Check for generic array loads from
1511     // the primary supertype array and also force them to the supertype cache
1512     // alias index.  Since the same load can reach both, we need to merge
1513     // these 2 disparate memories into the same alias class.  Since the
1514     // primary supertype array is read-only, there's no chance of confusion
1515     // where we bypass an array load and an array store.
1516     int primary_supers_offset = in_bytes(Klass::primary_supers_offset());
1517     if (offset == Type::OffsetBot ||
1518         (offset >= primary_supers_offset &&
1519          offset < (int)(primary_supers_offset + Klass::primary_super_limit() * wordSize)) ||
1520         offset == (int)in_bytes(Klass::secondary_super_cache_offset())) {
1521       offset = in_bytes(Klass::secondary_super_cache_offset());
1522       tj = tk = TypeKlassPtr::make( TypePtr::NotNull, tk->klass(), offset );
1523     }
1524   }
1525 
1526   // Flatten all Raw pointers together.
1527   if (tj->base() == Type::RawPtr)
1528     tj = TypeRawPtr::BOTTOM;
1529 
1530   if (tj->base() == Type::AnyPtr)
1531     tj = TypePtr::BOTTOM;      // An error, which the caller must check for.
1532 
1533   // Flatten all to bottom for now
1534   switch( _AliasLevel ) {
1535   case 0:
1536     tj = TypePtr::BOTTOM;
1537     break;
1538   case 1:                       // Flatten to: oop, static, field or array
1539     switch (tj->base()) {
1540     //case Type::AryPtr: tj = TypeAryPtr::RANGE;    break;
1541     case Type::RawPtr:   tj = TypeRawPtr::BOTTOM;   break;
1542     case Type::AryPtr:   // do not distinguish arrays at all
1543     case Type::InstPtr:  tj = TypeInstPtr::BOTTOM;  break;
1544     case Type::KlassPtr: tj = TypeKlassPtr::OBJECT; break;
1545     case Type::AnyPtr:   tj = TypePtr::BOTTOM;      break;  // caller checks it
1546     default: ShouldNotReachHere();
1547     }
1548     break;
1549   case 2:                       // No collapsing at level 2; keep all splits
1550   case 3:                       // No collapsing at level 3; keep all splits
1551     break;
1552   default:
1553     Unimplemented();
1554   }
1555 
1556   offset = tj->offset();
1557   assert( offset != Type::OffsetTop, "Offset has fallen from constant" );
1558 
1559   assert( (offset != Type::OffsetBot && tj->base() != Type::AryPtr) ||
1560           (offset == Type::OffsetBot && tj->base() == Type::AryPtr) ||
1561           (offset == Type::OffsetBot && tj == TypeOopPtr::BOTTOM) ||
1562           (offset == Type::OffsetBot && tj == TypePtr::BOTTOM) ||
1563           (offset == oopDesc::mark_offset_in_bytes() && tj->base() == Type::AryPtr) ||
1564           (offset == oopDesc::klass_offset_in_bytes() && tj->base() == Type::AryPtr) ||
1565           (offset == arrayOopDesc::length_offset_in_bytes() && tj->base() == Type::AryPtr)  ,
1566           "For oops, klasses, raw offset must be constant; for arrays the offset is never known" );
1567   assert( tj->ptr() != TypePtr::TopPTR &&
1568           tj->ptr() != TypePtr::AnyNull &&
1569           tj->ptr() != TypePtr::Null, "No imprecise addresses" );
1570 //    assert( tj->ptr() != TypePtr::Constant ||
1571 //            tj->base() == Type::RawPtr ||
1572 //            tj->base() == Type::KlassPtr, "No constant oop addresses" );
1573 
1574   return tj;
1575 }
1576 
1577 void Compile::AliasType::Init(int i, const TypePtr* at) {
1578   _index = i;
1579   _adr_type = at;
1580   _field = NULL;
1581   _element = NULL;
1582   _is_rewritable = true; // default
1583   const TypeOopPtr *atoop = (at != NULL) ? at->isa_oopptr() : NULL;
1584   if (atoop != NULL && atoop->is_known_instance()) {
1585     const TypeOopPtr *gt = atoop->cast_to_instance_id(TypeOopPtr::InstanceBot);
1586     _general_index = Compile::current()->get_alias_index(gt);
1587   } else {
1588     _general_index = 0;
1589   }
1590 }
1591 
1592 //---------------------------------print_on------------------------------------
1593 #ifndef PRODUCT
1594 void Compile::AliasType::print_on(outputStream* st) {
1595   if (index() < 10)
1596         st->print("@ <%d> ", index());
1597   else  st->print("@ <%d>",  index());
1598   st->print(is_rewritable() ? "   " : " RO");
1599   int offset = adr_type()->offset();
1600   if (offset == Type::OffsetBot)
1601         st->print(" +any");
1602   else  st->print(" +%-3d", offset);
1603   st->print(" in ");
1604   adr_type()->dump_on(st);
1605   const TypeOopPtr* tjp = adr_type()->isa_oopptr();
1606   if (field() != NULL && tjp) {
1607     if (tjp->klass()  != field()->holder() ||
1608         tjp->offset() != field()->offset_in_bytes()) {
1609       st->print(" != ");
1610       field()->print();
1611       st->print(" ***");
1612     }
1613   }
1614 }
1615 
1616 void print_alias_types() {
1617   Compile* C = Compile::current();
1618   tty->print_cr("--- Alias types, AliasIdxBot .. %d", C->num_alias_types()-1);
1619   for (int idx = Compile::AliasIdxBot; idx < C->num_alias_types(); idx++) {
1620     C->alias_type(idx)->print_on(tty);
1621     tty->cr();
1622   }
1623 }
1624 #endif
1625 
1626 
1627 //----------------------------probe_alias_cache--------------------------------
1628 Compile::AliasCacheEntry* Compile::probe_alias_cache(const TypePtr* adr_type) {
1629   intptr_t key = (intptr_t) adr_type;
1630   key ^= key >> logAliasCacheSize;
1631   return &_alias_cache[key & right_n_bits(logAliasCacheSize)];
1632 }
1633 
1634 
1635 //-----------------------------grow_alias_types--------------------------------
1636 void Compile::grow_alias_types() {
1637   const int old_ats  = _max_alias_types; // how many before?
1638   const int new_ats  = old_ats;          // how many more?
1639   const int grow_ats = old_ats+new_ats;  // how many now?
1640   _max_alias_types = grow_ats;
1641   _alias_types =  REALLOC_ARENA_ARRAY(comp_arena(), AliasType*, _alias_types, old_ats, grow_ats);
1642   AliasType* ats =    NEW_ARENA_ARRAY(comp_arena(), AliasType, new_ats);
1643   Copy::zero_to_bytes(ats, sizeof(AliasType)*new_ats);
1644   for (int i = 0; i < new_ats; i++)  _alias_types[old_ats+i] = &ats[i];
1645 }
1646 
1647 
1648 //--------------------------------find_alias_type------------------------------
1649 Compile::AliasType* Compile::find_alias_type(const TypePtr* adr_type, bool no_create, ciField* original_field) {
1650   if (_AliasLevel == 0)
1651     return alias_type(AliasIdxBot);
1652 
1653   AliasCacheEntry* ace = probe_alias_cache(adr_type);
1654   if (ace->_adr_type == adr_type) {
1655     return alias_type(ace->_index);
1656   }
1657 
1658   // Handle special cases.
1659   if (adr_type == NULL)             return alias_type(AliasIdxTop);
1660   if (adr_type == TypePtr::BOTTOM)  return alias_type(AliasIdxBot);
1661 
1662   // Do it the slow way.
1663   const TypePtr* flat = flatten_alias_type(adr_type);
1664 
1665 #ifdef ASSERT
1666   assert(flat == flatten_alias_type(flat), "idempotent");
1667   assert(flat != TypePtr::BOTTOM,     "cannot alias-analyze an untyped ptr");
1668   if (flat->isa_oopptr() && !flat->isa_klassptr()) {
1669     const TypeOopPtr* foop = flat->is_oopptr();
1670     // Scalarizable allocations have exact klass always.
1671     bool exact = !foop->klass_is_exact() || foop->is_known_instance();
1672     const TypePtr* xoop = foop->cast_to_exactness(exact)->is_ptr();
1673     assert(foop == flatten_alias_type(xoop), "exactness must not affect alias type");
1674   }
1675   assert(flat == flatten_alias_type(flat), "exact bit doesn't matter");
1676 #endif
1677 
1678   int idx = AliasIdxTop;
1679   for (int i = 0; i < num_alias_types(); i++) {
1680     if (alias_type(i)->adr_type() == flat) {
1681       idx = i;
1682       break;
1683     }
1684   }
1685 
1686   if (idx == AliasIdxTop) {
1687     if (no_create)  return NULL;
1688     // Grow the array if necessary.
1689     if (_num_alias_types == _max_alias_types)  grow_alias_types();
1690     // Add a new alias type.
1691     idx = _num_alias_types++;
1692     _alias_types[idx]->Init(idx, flat);
1693     if (flat == TypeInstPtr::KLASS)  alias_type(idx)->set_rewritable(false);
1694     if (flat == TypeAryPtr::RANGE)   alias_type(idx)->set_rewritable(false);
1695     if (flat->isa_instptr()) {
1696       if (flat->offset() == java_lang_Class::klass_offset_in_bytes()
1697           && flat->is_instptr()->klass() == env()->Class_klass())
1698         alias_type(idx)->set_rewritable(false);
1699     }
1700     if (flat->isa_aryptr()) {
1701 #ifdef ASSERT
1702       const int header_size_min  = arrayOopDesc::base_offset_in_bytes(T_BYTE);
1703       // (T_BYTE has the weakest alignment and size restrictions...)
1704       assert(flat->offset() < header_size_min, "array body reference must be OffsetBot");
1705 #endif
1706       if (flat->offset() == TypePtr::OffsetBot) {
1707         alias_type(idx)->set_element(flat->is_aryptr()->elem());
1708       }
1709     }
1710     if (flat->isa_klassptr()) {
1711       if (flat->offset() == in_bytes(Klass::super_check_offset_offset()))
1712         alias_type(idx)->set_rewritable(false);
1713       if (flat->offset() == in_bytes(Klass::modifier_flags_offset()))
1714         alias_type(idx)->set_rewritable(false);
1715       if (flat->offset() == in_bytes(Klass::access_flags_offset()))
1716         alias_type(idx)->set_rewritable(false);
1717       if (flat->offset() == in_bytes(Klass::java_mirror_offset()))
1718         alias_type(idx)->set_rewritable(false);
1719     }
1720     // %%% (We would like to finalize JavaThread::threadObj_offset(),
1721     // but the base pointer type is not distinctive enough to identify
1722     // references into JavaThread.)
1723 
1724     // Check for final fields.
1725     const TypeInstPtr* tinst = flat->isa_instptr();
1726     if (tinst && tinst->offset() >= instanceOopDesc::base_offset_in_bytes()) {
1727       ciField* field;
1728       if (tinst->const_oop() != NULL &&
1729           tinst->klass() == ciEnv::current()->Class_klass() &&
1730           tinst->offset() >= (tinst->klass()->as_instance_klass()->size_helper() * wordSize)) {
1731         // static field
1732         ciInstanceKlass* k = tinst->const_oop()->as_instance()->java_lang_Class_klass()->as_instance_klass();
1733         field = k->get_field_by_offset(tinst->offset(), true);
1734       } else {
1735         ciInstanceKlass *k = tinst->klass()->as_instance_klass();
1736         field = k->get_field_by_offset(tinst->offset(), false);
1737       }
1738       assert(field == NULL ||
1739              original_field == NULL ||
1740              (field->holder() == original_field->holder() &&
1741               field->offset() == original_field->offset() &&
1742               field->is_static() == original_field->is_static()), "wrong field?");
1743       // Set field() and is_rewritable() attributes.
1744       if (field != NULL)  alias_type(idx)->set_field(field);
1745     }
1746   }
1747 
1748   // Fill the cache for next time.
1749   ace->_adr_type = adr_type;
1750   ace->_index    = idx;
1751   assert(alias_type(adr_type) == alias_type(idx),  "type must be installed");
1752 
1753   // Might as well try to fill the cache for the flattened version, too.
1754   AliasCacheEntry* face = probe_alias_cache(flat);
1755   if (face->_adr_type == NULL) {
1756     face->_adr_type = flat;
1757     face->_index    = idx;
1758     assert(alias_type(flat) == alias_type(idx), "flat type must work too");
1759   }
1760 
1761   return alias_type(idx);
1762 }
1763 
1764 
1765 Compile::AliasType* Compile::alias_type(ciField* field) {
1766   const TypeOopPtr* t;
1767   if (field->is_static())
1768     t = TypeInstPtr::make(field->holder()->java_mirror());
1769   else
1770     t = TypeOopPtr::make_from_klass_raw(field->holder());
1771   AliasType* atp = alias_type(t->add_offset(field->offset_in_bytes()), field);
1772   assert((field->is_final() || field->is_stable()) == !atp->is_rewritable(), "must get the rewritable bits correct");
1773   return atp;
1774 }
1775 
1776 
1777 //------------------------------have_alias_type--------------------------------
1778 bool Compile::have_alias_type(const TypePtr* adr_type) {
1779   AliasCacheEntry* ace = probe_alias_cache(adr_type);
1780   if (ace->_adr_type == adr_type) {
1781     return true;
1782   }
1783 
1784   // Handle special cases.
1785   if (adr_type == NULL)             return true;
1786   if (adr_type == TypePtr::BOTTOM)  return true;
1787 
1788   return find_alias_type(adr_type, true, NULL) != NULL;
1789 }
1790 
1791 //-----------------------------must_alias--------------------------------------
1792 // True if all values of the given address type are in the given alias category.
1793 bool Compile::must_alias(const TypePtr* adr_type, int alias_idx) {
1794   if (alias_idx == AliasIdxBot)         return true;  // the universal category
1795   if (adr_type == NULL)                 return true;  // NULL serves as TypePtr::TOP
1796   if (alias_idx == AliasIdxTop)         return false; // the empty category
1797   if (adr_type->base() == Type::AnyPtr) return false; // TypePtr::BOTTOM or its twins
1798 
1799   // the only remaining possible overlap is identity
1800   int adr_idx = get_alias_index(adr_type);
1801   assert(adr_idx != AliasIdxBot && adr_idx != AliasIdxTop, "");
1802   assert(adr_idx == alias_idx ||
1803          (alias_type(alias_idx)->adr_type() != TypeOopPtr::BOTTOM
1804           && adr_type                       != TypeOopPtr::BOTTOM),
1805          "should not be testing for overlap with an unsafe pointer");
1806   return adr_idx == alias_idx;
1807 }
1808 
1809 //------------------------------can_alias--------------------------------------
1810 // True if any values of the given address type are in the given alias category.
1811 bool Compile::can_alias(const TypePtr* adr_type, int alias_idx) {
1812   if (alias_idx == AliasIdxTop)         return false; // the empty category
1813   if (adr_type == NULL)                 return false; // NULL serves as TypePtr::TOP
1814   if (alias_idx == AliasIdxBot)         return true;  // the universal category
1815   if (adr_type->base() == Type::AnyPtr) return true;  // TypePtr::BOTTOM or its twins
1816 
1817   // the only remaining possible overlap is identity
1818   int adr_idx = get_alias_index(adr_type);
1819   assert(adr_idx != AliasIdxBot && adr_idx != AliasIdxTop, "");
1820   return adr_idx == alias_idx;
1821 }
1822 
1823 
1824 
1825 //---------------------------pop_warm_call-------------------------------------
1826 WarmCallInfo* Compile::pop_warm_call() {
1827   WarmCallInfo* wci = _warm_calls;
1828   if (wci != NULL)  _warm_calls = wci->remove_from(wci);
1829   return wci;
1830 }
1831 
1832 //----------------------------Inline_Warm--------------------------------------
1833 int Compile::Inline_Warm() {
1834   // If there is room, try to inline some more warm call sites.
1835   // %%% Do a graph index compaction pass when we think we're out of space?
1836   if (!InlineWarmCalls)  return 0;
1837 
1838   int calls_made_hot = 0;
1839   int room_to_grow   = NodeCountInliningCutoff - unique();
1840   int amount_to_grow = MIN2(room_to_grow, (int)NodeCountInliningStep);
1841   int amount_grown   = 0;
1842   WarmCallInfo* call;
1843   while (amount_to_grow > 0 && (call = pop_warm_call()) != NULL) {
1844     int est_size = (int)call->size();
1845     if (est_size > (room_to_grow - amount_grown)) {
1846       // This one won't fit anyway.  Get rid of it.
1847       call->make_cold();
1848       continue;
1849     }
1850     call->make_hot();
1851     calls_made_hot++;
1852     amount_grown   += est_size;
1853     amount_to_grow -= est_size;
1854   }
1855 
1856   if (calls_made_hot > 0)  set_major_progress();
1857   return calls_made_hot;
1858 }
1859 
1860 
1861 //----------------------------Finish_Warm--------------------------------------
1862 void Compile::Finish_Warm() {
1863   if (!InlineWarmCalls)  return;
1864   if (failing())  return;
1865   if (warm_calls() == NULL)  return;
1866 
1867   // Clean up loose ends, if we are out of space for inlining.
1868   WarmCallInfo* call;
1869   while ((call = pop_warm_call()) != NULL) {
1870     call->make_cold();
1871   }
1872 }
1873 
1874 //---------------------cleanup_loop_predicates-----------------------
1875 // Remove the opaque nodes that protect the predicates so that all unused
1876 // checks and uncommon_traps will be eliminated from the ideal graph
1877 void Compile::cleanup_loop_predicates(PhaseIterGVN &igvn) {
1878   if (predicate_count()==0) return;
1879   for (int i = predicate_count(); i > 0; i--) {
1880     Node * n = predicate_opaque1_node(i-1);
1881     assert(n->Opcode() == Op_Opaque1, "must be");
1882     igvn.replace_node(n, n->in(1));
1883   }
1884   assert(predicate_count()==0, "should be clean!");
1885 }
1886 
1887 void Compile::add_range_check_cast(Node* n) {
1888   assert(n->isa_CastII()->has_range_check(), "CastII should have range check dependency");
1889   assert(!_range_check_casts->contains(n), "duplicate entry in range check casts");
1890   _range_check_casts->append(n);
1891 }
1892 
1893 // Remove all range check dependent CastIINodes.
1894 void Compile::remove_range_check_casts(PhaseIterGVN &igvn) {
1895   for (int i = range_check_cast_count(); i > 0; i--) {
1896     Node* cast = range_check_cast_node(i-1);
1897     assert(cast->isa_CastII()->has_range_check(), "CastII should have range check dependency");
1898     igvn.replace_node(cast, cast->in(1));
1899   }
1900   assert(range_check_cast_count() == 0, "should be empty");
1901 }
1902 
1903 // StringOpts and late inlining of string methods
1904 void Compile::inline_string_calls(bool parse_time) {
1905   {
1906     // remove useless nodes to make the usage analysis simpler
1907     ResourceMark rm;
1908     PhaseRemoveUseless pru(initial_gvn(), for_igvn());
1909   }
1910 
1911   {
1912     ResourceMark rm;
1913     print_method(PHASE_BEFORE_STRINGOPTS, 3);
1914     PhaseStringOpts pso(initial_gvn(), for_igvn());
1915     print_method(PHASE_AFTER_STRINGOPTS, 3);
1916   }
1917 
1918   // now inline anything that we skipped the first time around
1919   if (!parse_time) {
1920     _late_inlines_pos = _late_inlines.length();
1921   }
1922 
1923   while (_string_late_inlines.length() > 0) {
1924     CallGenerator* cg = _string_late_inlines.pop();
1925     cg->do_late_inline();
1926     if (failing())  return;
1927   }
1928   _string_late_inlines.trunc_to(0);
1929 }
1930 
1931 // Late inlining of boxing methods
1932 void Compile::inline_boxing_calls(PhaseIterGVN& igvn) {
1933   if (_boxing_late_inlines.length() > 0) {
1934     assert(has_boxed_value(), "inconsistent");
1935 
1936     PhaseGVN* gvn = initial_gvn();
1937     set_inlining_incrementally(true);
1938 
1939     assert( igvn._worklist.size() == 0, "should be done with igvn" );
1940     for_igvn()->clear();
1941     gvn->replace_with(&igvn);
1942 
1943     _late_inlines_pos = _late_inlines.length();
1944 
1945     while (_boxing_late_inlines.length() > 0) {
1946       CallGenerator* cg = _boxing_late_inlines.pop();
1947       cg->do_late_inline();
1948       if (failing())  return;
1949     }
1950     _boxing_late_inlines.trunc_to(0);
1951 
1952     {
1953       ResourceMark rm;
1954       PhaseRemoveUseless pru(gvn, for_igvn());
1955     }
1956 
1957     igvn = PhaseIterGVN(gvn);
1958     igvn.optimize();
1959 
1960     set_inlining_progress(false);
1961     set_inlining_incrementally(false);
1962   }
1963 }
1964 
1965 void Compile::inline_incrementally_one(PhaseIterGVN& igvn) {
1966   assert(IncrementalInline, "incremental inlining should be on");
1967   PhaseGVN* gvn = initial_gvn();
1968 
1969   set_inlining_progress(false);
1970   for_igvn()->clear();
1971   gvn->replace_with(&igvn);
1972 
1973   int i = 0;
1974 
1975   for (; i <_late_inlines.length() && !inlining_progress(); i++) {
1976     CallGenerator* cg = _late_inlines.at(i);
1977     _late_inlines_pos = i+1;
1978     cg->do_late_inline();
1979     if (failing())  return;
1980   }
1981   int j = 0;
1982   for (; i < _late_inlines.length(); i++, j++) {
1983     _late_inlines.at_put(j, _late_inlines.at(i));
1984   }
1985   _late_inlines.trunc_to(j);
1986 
1987   {
1988     ResourceMark rm;
1989     PhaseRemoveUseless pru(gvn, for_igvn());
1990   }
1991 
1992   igvn = PhaseIterGVN(gvn);
1993 }
1994 
1995 // Perform incremental inlining until bound on number of live nodes is reached
1996 void Compile::inline_incrementally(PhaseIterGVN& igvn) {
1997   PhaseGVN* gvn = initial_gvn();
1998 
1999   set_inlining_incrementally(true);
2000   set_inlining_progress(true);
2001   uint low_live_nodes = 0;
2002 
2003   while(inlining_progress() && _late_inlines.length() > 0) {
2004 
2005     if (live_nodes() > (uint)LiveNodeCountInliningCutoff) {
2006       if (low_live_nodes < (uint)LiveNodeCountInliningCutoff * 8 / 10) {
2007         // PhaseIdealLoop is expensive so we only try it once we are
2008         // out of live nodes and we only try it again if the previous
2009         // helped got the number of nodes down significantly
2010         PhaseIdealLoop ideal_loop( igvn, false, true );
2011         if (failing())  return;
2012         low_live_nodes = live_nodes();
2013         _major_progress = true;
2014       }
2015 
2016       if (live_nodes() > (uint)LiveNodeCountInliningCutoff) {
2017         break;
2018       }
2019     }
2020 
2021     inline_incrementally_one(igvn);
2022 
2023     if (failing())  return;
2024 
2025     igvn.optimize();
2026 
2027     if (failing())  return;
2028   }
2029 
2030   assert( igvn._worklist.size() == 0, "should be done with igvn" );
2031 
2032   if (_string_late_inlines.length() > 0) {
2033     assert(has_stringbuilder(), "inconsistent");
2034     for_igvn()->clear();
2035     initial_gvn()->replace_with(&igvn);
2036 
2037     inline_string_calls(false);
2038 
2039     if (failing())  return;
2040 
2041     {
2042       ResourceMark rm;
2043       PhaseRemoveUseless pru(initial_gvn(), for_igvn());
2044     }
2045 
2046     igvn = PhaseIterGVN(gvn);
2047 
2048     igvn.optimize();
2049   }
2050 
2051   set_inlining_incrementally(false);
2052 }
2053 
2054 
2055 //------------------------------Optimize---------------------------------------
2056 // Given a graph, optimize it.
2057 void Compile::Optimize() {
2058   TracePhase t1("optimizer", &_t_optimizer, true);
2059 
2060 #ifndef PRODUCT
2061   if (env()->break_at_compile()) {
2062     BREAKPOINT;
2063   }
2064 
2065 #endif
2066 
2067   ResourceMark rm;
2068   int          loop_opts_cnt;
2069 
2070   NOT_PRODUCT( verify_graph_edges(); )
2071 
2072   print_method(PHASE_AFTER_PARSING);
2073 
2074  {
2075   // Iterative Global Value Numbering, including ideal transforms
2076   // Initialize IterGVN with types and values from parse-time GVN
2077   PhaseIterGVN igvn(initial_gvn());
2078   {
2079     NOT_PRODUCT( TracePhase t2("iterGVN", &_t_iterGVN, TimeCompiler); )
2080     igvn.optimize();
2081   }
2082 
2083   print_method(PHASE_ITER_GVN1, 2);
2084 
2085   if (failing())  return;
2086 
2087   {
2088     NOT_PRODUCT( TracePhase t2("incrementalInline", &_t_incrInline, TimeCompiler); )
2089     inline_incrementally(igvn);
2090   }
2091 
2092   print_method(PHASE_INCREMENTAL_INLINE, 2);
2093 
2094   if (failing())  return;
2095 
2096   if (eliminate_boxing()) {
2097     NOT_PRODUCT( TracePhase t2("incrementalInline", &_t_incrInline, TimeCompiler); )
2098     // Inline valueOf() methods now.
2099     inline_boxing_calls(igvn);
2100 
2101     if (AlwaysIncrementalInline) {
2102       inline_incrementally(igvn);
2103     }
2104 
2105     print_method(PHASE_INCREMENTAL_BOXING_INLINE, 2);
2106 
2107     if (failing())  return;
2108   }
2109 
2110   // Remove the speculative part of types and clean up the graph from
2111   // the extra CastPP nodes whose only purpose is to carry them. Do
2112   // that early so that optimizations are not disrupted by the extra
2113   // CastPP nodes.
2114   remove_speculative_types(igvn);
2115 
2116   // No more new expensive nodes will be added to the list from here
2117   // so keep only the actual candidates for optimizations.
2118   cleanup_expensive_nodes(igvn);
2119 
2120   if (!failing() && RenumberLiveNodes && live_nodes() + NodeLimitFudgeFactor < unique()) {
2121     NOT_PRODUCT(Compile::TracePhase t2("", &_t_renumberLive, TimeCompiler);)
2122     initial_gvn()->replace_with(&igvn);
2123     for_igvn()->clear();
2124     Unique_Node_List new_worklist(C->comp_arena());
2125     {
2126       ResourceMark rm;
2127       PhaseRenumberLive prl = PhaseRenumberLive(initial_gvn(), for_igvn(), &new_worklist);
2128     }
2129     set_for_igvn(&new_worklist);
2130     igvn = PhaseIterGVN(initial_gvn());
2131     igvn.optimize();
2132   }
2133 
2134   // Perform escape analysis
2135   if (_do_escape_analysis && ConnectionGraph::has_candidates(this)) {
2136     if (has_loops()) {
2137       // Cleanup graph (remove dead nodes).
2138       TracePhase t2("idealLoop", &_t_idealLoop, true);
2139       PhaseIdealLoop ideal_loop( igvn, false, true );
2140       if (major_progress()) print_method(PHASE_PHASEIDEAL_BEFORE_EA, 2);
2141       if (failing())  return;
2142     }
2143     ConnectionGraph::do_analysis(this, &igvn);
2144 
2145     if (failing())  return;
2146 
2147     // Optimize out fields loads from scalar replaceable allocations.
2148     igvn.optimize();
2149     print_method(PHASE_ITER_GVN_AFTER_EA, 2);
2150 
2151     if (failing())  return;
2152 
2153     if (congraph() != NULL && macro_count() > 0) {
2154       NOT_PRODUCT( TracePhase t2("macroEliminate", &_t_macroEliminate, TimeCompiler); )
2155       PhaseMacroExpand mexp(igvn);
2156       mexp.eliminate_macro_nodes();
2157       igvn.set_delay_transform(false);
2158 
2159       igvn.optimize();
2160       print_method(PHASE_ITER_GVN_AFTER_ELIMINATION, 2);
2161 
2162       if (failing())  return;
2163     }
2164   }
2165 
2166   // Loop transforms on the ideal graph.  Range Check Elimination,
2167   // peeling, unrolling, etc.
2168 
2169   // Set loop opts counter
2170   loop_opts_cnt = num_loop_opts();
2171   if((loop_opts_cnt > 0) && (has_loops() || has_split_ifs())) {
2172     {
2173       TracePhase t2("idealLoop", &_t_idealLoop, true);
2174       PhaseIdealLoop ideal_loop( igvn, true );
2175       loop_opts_cnt--;
2176       if (major_progress()) print_method(PHASE_PHASEIDEALLOOP1, 2);
2177       if (failing())  return;
2178     }
2179     // Loop opts pass if partial peeling occurred in previous pass
2180     if(PartialPeelLoop && major_progress() && (loop_opts_cnt > 0)) {
2181       TracePhase t3("idealLoop", &_t_idealLoop, true);
2182       PhaseIdealLoop ideal_loop( igvn, false );
2183       loop_opts_cnt--;
2184       if (major_progress()) print_method(PHASE_PHASEIDEALLOOP2, 2);
2185       if (failing())  return;
2186     }
2187     // Loop opts pass for loop-unrolling before CCP
2188     if(major_progress() && (loop_opts_cnt > 0)) {
2189       TracePhase t4("idealLoop", &_t_idealLoop, true);
2190       PhaseIdealLoop ideal_loop( igvn, false );
2191       loop_opts_cnt--;
2192       if (major_progress()) print_method(PHASE_PHASEIDEALLOOP3, 2);
2193     }
2194     if (!failing()) {
2195       // Verify that last round of loop opts produced a valid graph
2196       NOT_PRODUCT( TracePhase t2("idealLoopVerify", &_t_idealLoopVerify, TimeCompiler); )
2197       PhaseIdealLoop::verify(igvn);
2198     }
2199   }
2200   if (failing())  return;
2201 
2202   // Conditional Constant Propagation;
2203   PhaseCCP ccp( &igvn );
2204   assert( true, "Break here to ccp.dump_nodes_and_types(_root,999,1)");
2205   {
2206     TracePhase t2("ccp", &_t_ccp, true);
2207     ccp.do_transform();
2208   }
2209   print_method(PHASE_CPP1, 2);
2210 
2211   assert( true, "Break here to ccp.dump_old2new_map()");
2212 
2213   // Iterative Global Value Numbering, including ideal transforms
2214   {
2215     NOT_PRODUCT( TracePhase t2("iterGVN2", &_t_iterGVN2, TimeCompiler); )
2216     igvn = ccp;
2217     igvn.optimize();
2218   }
2219 
2220   print_method(PHASE_ITER_GVN2, 2);
2221 
2222   if (failing())  return;
2223 
2224   // Loop transforms on the ideal graph.  Range Check Elimination,
2225   // peeling, unrolling, etc.
2226   if(loop_opts_cnt > 0) {
2227     debug_only( int cnt = 0; );
2228     while(major_progress() && (loop_opts_cnt > 0)) {
2229       TracePhase t2("idealLoop", &_t_idealLoop, true);
2230       assert( cnt++ < 40, "infinite cycle in loop optimization" );
2231       PhaseIdealLoop ideal_loop( igvn, true);
2232       loop_opts_cnt--;
2233       if (major_progress()) print_method(PHASE_PHASEIDEALLOOP_ITERATIONS, 2);
2234       if (failing())  return;
2235     }
2236   }
2237 
2238   {
2239     // Verify that all previous optimizations produced a valid graph
2240     // at least to this point, even if no loop optimizations were done.
2241     NOT_PRODUCT( TracePhase t2("idealLoopVerify", &_t_idealLoopVerify, TimeCompiler); )
2242     PhaseIdealLoop::verify(igvn);
2243   }
2244 
2245   if (range_check_cast_count() > 0) {
2246     // No more loop optimizations. Remove all range check dependent CastIINodes.
2247     C->remove_range_check_casts(igvn);
2248     igvn.optimize();
2249   }
2250 
2251   {
2252     NOT_PRODUCT( TracePhase t2("macroExpand", &_t_macroExpand, TimeCompiler); )
2253     PhaseMacroExpand  mex(igvn);
2254     if (mex.expand_macro_nodes()) {
2255       assert(failing(), "must bail out w/ explicit message");
2256       return;
2257     }
2258   }
2259 
2260  } // (End scope of igvn; run destructor if necessary for asserts.)
2261 
2262   dump_inlining();
2263   // A method with only infinite loops has no edges entering loops from root
2264   {
2265     NOT_PRODUCT( TracePhase t2("graphReshape", &_t_graphReshaping, TimeCompiler); )
2266     if (final_graph_reshaping()) {
2267       assert(failing(), "must bail out w/ explicit message");
2268       return;
2269     }
2270   }
2271 
2272   print_method(PHASE_OPTIMIZE_FINISHED, 2);
2273 }
2274 
2275 
2276 //------------------------------Code_Gen---------------------------------------
2277 // Given a graph, generate code for it
2278 void Compile::Code_Gen() {
2279   if (failing()) {
2280     return;
2281   }
2282 
2283   // Perform instruction selection.  You might think we could reclaim Matcher
2284   // memory PDQ, but actually the Matcher is used in generating spill code.
2285   // Internals of the Matcher (including some VectorSets) must remain live
2286   // for awhile - thus I cannot reclaim Matcher memory lest a VectorSet usage
2287   // set a bit in reclaimed memory.
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   Matcher matcher;
2294   _matcher = &matcher;
2295   {
2296     TracePhase t2("matcher", &_t_matcher, true);
2297     matcher.match();
2298   }
2299   // In debug mode can dump m._nodes.dump() for mapping of ideal to machine
2300   // nodes.  Mapping is only valid at the root of each matched subtree.
2301   NOT_PRODUCT( verify_graph_edges(); )
2302 
2303   // If you have too many nodes, or if matching has failed, bail out
2304   check_node_count(0, "out of nodes matching instructions");
2305   if (failing()) {
2306     return;
2307   }
2308 
2309   // Build a proper-looking CFG
2310   PhaseCFG cfg(node_arena(), root(), matcher);
2311   _cfg = &cfg;
2312   {
2313     NOT_PRODUCT( TracePhase t2("scheduler", &_t_scheduler, TimeCompiler); )
2314     bool success = cfg.do_global_code_motion();
2315     if (!success) {
2316       return;
2317     }
2318 
2319     print_method(PHASE_GLOBAL_CODE_MOTION, 2);
2320     NOT_PRODUCT( verify_graph_edges(); )
2321     debug_only( cfg.verify(); )
2322   }
2323 
2324   PhaseChaitin regalloc(unique(), cfg, matcher);
2325   _regalloc = &regalloc;
2326   {
2327     TracePhase t2("regalloc", &_t_registerAllocation, true);
2328     // Perform register allocation.  After Chaitin, use-def chains are
2329     // no longer accurate (at spill code) and so must be ignored.
2330     // Node->LRG->reg mappings are still accurate.
2331     _regalloc->Register_Allocate();
2332 
2333     // Bail out if the allocator builds too many nodes
2334     if (failing()) {
2335       return;
2336     }
2337   }
2338 
2339   // Prior to register allocation we kept empty basic blocks in case the
2340   // the allocator needed a place to spill.  After register allocation we
2341   // are not adding any new instructions.  If any basic block is empty, we
2342   // can now safely remove it.
2343   {
2344     NOT_PRODUCT( TracePhase t2("blockOrdering", &_t_blockOrdering, TimeCompiler); )
2345     cfg.remove_empty_blocks();
2346     if (do_freq_based_layout()) {
2347       PhaseBlockLayout layout(cfg);
2348     } else {
2349       cfg.set_loop_alignment();
2350     }
2351     cfg.fixup_flow();
2352   }
2353 
2354   // Apply peephole optimizations
2355   if( OptoPeephole ) {
2356     NOT_PRODUCT( TracePhase t2("peephole", &_t_peephole, TimeCompiler); )
2357     PhasePeephole peep( _regalloc, cfg);
2358     peep.do_transform();
2359   }
2360 
2361   // Do late expand if CPU requires this.
2362   if (Matcher::require_postalloc_expand) {
2363     NOT_PRODUCT(TracePhase t2c("postalloc_expand", &_t_postalloc_expand, true));
2364     cfg.postalloc_expand(_regalloc);
2365   }
2366 
2367   // Convert Nodes to instruction bits in a buffer
2368   {
2369     // %%%% workspace merge brought two timers together for one job
2370     TracePhase t2a("output", &_t_output, true);
2371     NOT_PRODUCT( TraceTime t2b(NULL, &_t_codeGeneration, TimeCompiler, false); )
2372     Output();
2373   }
2374 
2375   print_method(PHASE_FINAL_CODE);
2376 
2377   // He's dead, Jim.
2378   _cfg     = (PhaseCFG*)0xdeadbeef;
2379   _regalloc = (PhaseChaitin*)0xdeadbeef;
2380 }
2381 
2382 
2383 //------------------------------dump_asm---------------------------------------
2384 // Dump formatted assembly
2385 #ifndef PRODUCT
2386 void Compile::dump_asm(int *pcs, uint pc_limit) {
2387   bool cut_short = false;
2388   tty->print_cr("#");
2389   tty->print("#  ");  _tf->dump();  tty->cr();
2390   tty->print_cr("#");
2391 
2392   // For all blocks
2393   int pc = 0x0;                 // Program counter
2394   char starts_bundle = ' ';
2395   _regalloc->dump_frame();
2396 
2397   Node *n = NULL;
2398   for (uint i = 0; i < _cfg->number_of_blocks(); i++) {
2399     if (VMThread::should_terminate()) {
2400       cut_short = true;
2401       break;
2402     }
2403     Block* block = _cfg->get_block(i);
2404     if (block->is_connector() && !Verbose) {
2405       continue;
2406     }
2407     n = block->head();
2408     if (pcs && n->_idx < pc_limit) {
2409       tty->print("%3.3x   ", pcs[n->_idx]);
2410     } else {
2411       tty->print("      ");
2412     }
2413     block->dump_head(_cfg);
2414     if (block->is_connector()) {
2415       tty->print_cr("        # Empty connector block");
2416     } else if (block->num_preds() == 2 && block->pred(1)->is_CatchProj() && block->pred(1)->as_CatchProj()->_con == CatchProjNode::fall_through_index) {
2417       tty->print_cr("        # Block is sole successor of call");
2418     }
2419 
2420     // For all instructions
2421     Node *delay = NULL;
2422     for (uint j = 0; j < block->number_of_nodes(); j++) {
2423       if (VMThread::should_terminate()) {
2424         cut_short = true;
2425         break;
2426       }
2427       n = block->get_node(j);
2428       if (valid_bundle_info(n)) {
2429         Bundle* bundle = node_bundling(n);
2430         if (bundle->used_in_unconditional_delay()) {
2431           delay = n;
2432           continue;
2433         }
2434         if (bundle->starts_bundle()) {
2435           starts_bundle = '+';
2436         }
2437       }
2438 
2439       if (WizardMode) {
2440         n->dump();
2441       }
2442 
2443       if( !n->is_Region() &&    // Dont print in the Assembly
2444           !n->is_Phi() &&       // a few noisely useless nodes
2445           !n->is_Proj() &&
2446           !n->is_MachTemp() &&
2447           !n->is_SafePointScalarObject() &&
2448           !n->is_Catch() &&     // Would be nice to print exception table targets
2449           !n->is_MergeMem() &&  // Not very interesting
2450           !n->is_top() &&       // Debug info table constants
2451           !(n->is_Con() && !n->is_Mach())// Debug info table constants
2452           ) {
2453         if (pcs && n->_idx < pc_limit)
2454           tty->print("%3.3x", pcs[n->_idx]);
2455         else
2456           tty->print("   ");
2457         tty->print(" %c ", starts_bundle);
2458         starts_bundle = ' ';
2459         tty->print("\t");
2460         n->format(_regalloc, tty);
2461         tty->cr();
2462       }
2463 
2464       // If we have an instruction with a delay slot, and have seen a delay,
2465       // then back up and print it
2466       if (valid_bundle_info(n) && node_bundling(n)->use_unconditional_delay()) {
2467         assert(delay != NULL, "no unconditional delay instruction");
2468         if (WizardMode) delay->dump();
2469 
2470         if (node_bundling(delay)->starts_bundle())
2471           starts_bundle = '+';
2472         if (pcs && n->_idx < pc_limit)
2473           tty->print("%3.3x", pcs[n->_idx]);
2474         else
2475           tty->print("   ");
2476         tty->print(" %c ", starts_bundle);
2477         starts_bundle = ' ';
2478         tty->print("\t");
2479         delay->format(_regalloc, tty);
2480         tty->cr();
2481         delay = NULL;
2482       }
2483 
2484       // Dump the exception table as well
2485       if( n->is_Catch() && (Verbose || WizardMode) ) {
2486         // Print the exception table for this offset
2487         _handler_table.print_subtable_for(pc);
2488       }
2489     }
2490 
2491     if (pcs && n->_idx < pc_limit)
2492       tty->print_cr("%3.3x", pcs[n->_idx]);
2493     else
2494       tty->cr();
2495 
2496     assert(cut_short || delay == NULL, "no unconditional delay branch");
2497 
2498   } // End of per-block dump
2499   tty->cr();
2500 
2501   if (cut_short)  tty->print_cr("*** disassembly is cut short ***");
2502 }
2503 #endif
2504 
2505 //------------------------------Final_Reshape_Counts---------------------------
2506 // This class defines counters to help identify when a method
2507 // may/must be executed using hardware with only 24-bit precision.
2508 struct Final_Reshape_Counts : public StackObj {
2509   int  _call_count;             // count non-inlined 'common' calls
2510   int  _float_count;            // count float ops requiring 24-bit precision
2511   int  _double_count;           // count double ops requiring more precision
2512   int  _java_call_count;        // count non-inlined 'java' calls
2513   int  _inner_loop_count;       // count loops which need alignment
2514   VectorSet _visited;           // Visitation flags
2515   Node_List _tests;             // Set of IfNodes & PCTableNodes
2516 
2517   Final_Reshape_Counts() :
2518     _call_count(0), _float_count(0), _double_count(0),
2519     _java_call_count(0), _inner_loop_count(0),
2520     _visited( Thread::current()->resource_area() ) { }
2521 
2522   void inc_call_count  () { _call_count  ++; }
2523   void inc_float_count () { _float_count ++; }
2524   void inc_double_count() { _double_count++; }
2525   void inc_java_call_count() { _java_call_count++; }
2526   void inc_inner_loop_count() { _inner_loop_count++; }
2527 
2528   int  get_call_count  () const { return _call_count  ; }
2529   int  get_float_count () const { return _float_count ; }
2530   int  get_double_count() const { return _double_count; }
2531   int  get_java_call_count() const { return _java_call_count; }
2532   int  get_inner_loop_count() const { return _inner_loop_count; }
2533 };
2534 
2535 #ifdef ASSERT
2536 static bool oop_offset_is_sane(const TypeInstPtr* tp) {
2537   ciInstanceKlass *k = tp->klass()->as_instance_klass();
2538   // Make sure the offset goes inside the instance layout.
2539   return k->contains_field_offset(tp->offset());
2540   // Note that OffsetBot and OffsetTop are very negative.
2541 }
2542 #endif
2543 
2544 // Eliminate trivially redundant StoreCMs and accumulate their
2545 // precedence edges.
2546 void Compile::eliminate_redundant_card_marks(Node* n) {
2547   assert(n->Opcode() == Op_StoreCM, "expected StoreCM");
2548   if (n->in(MemNode::Address)->outcnt() > 1) {
2549     // There are multiple users of the same address so it might be
2550     // possible to eliminate some of the StoreCMs
2551     Node* mem = n->in(MemNode::Memory);
2552     Node* adr = n->in(MemNode::Address);
2553     Node* val = n->in(MemNode::ValueIn);
2554     Node* prev = n;
2555     bool done = false;
2556     // Walk the chain of StoreCMs eliminating ones that match.  As
2557     // long as it's a chain of single users then the optimization is
2558     // safe.  Eliminating partially redundant StoreCMs would require
2559     // cloning copies down the other paths.
2560     while (mem->Opcode() == Op_StoreCM && mem->outcnt() == 1 && !done) {
2561       if (adr == mem->in(MemNode::Address) &&
2562           val == mem->in(MemNode::ValueIn)) {
2563         // redundant StoreCM
2564         if (mem->req() > MemNode::OopStore) {
2565           // Hasn't been processed by this code yet.
2566           n->add_prec(mem->in(MemNode::OopStore));
2567         } else {
2568           // Already converted to precedence edge
2569           for (uint i = mem->req(); i < mem->len(); i++) {
2570             // Accumulate any precedence edges
2571             if (mem->in(i) != NULL) {
2572               n->add_prec(mem->in(i));
2573             }
2574           }
2575           // Everything above this point has been processed.
2576           done = true;
2577         }
2578         // Eliminate the previous StoreCM
2579         prev->set_req(MemNode::Memory, mem->in(MemNode::Memory));
2580         assert(mem->outcnt() == 0, "should be dead");
2581         mem->disconnect_inputs(NULL, this);
2582       } else {
2583         prev = mem;
2584       }
2585       mem = prev->in(MemNode::Memory);
2586     }
2587   }
2588 }
2589 
2590 //------------------------------final_graph_reshaping_impl----------------------
2591 // Implement items 1-5 from final_graph_reshaping below.
2592 void Compile::final_graph_reshaping_impl( Node *n, Final_Reshape_Counts &frc) {
2593 
2594   if ( n->outcnt() == 0 ) return; // dead node
2595   uint nop = n->Opcode();
2596 
2597   // Check for 2-input instruction with "last use" on right input.
2598   // Swap to left input.  Implements item (2).
2599   if( n->req() == 3 &&          // two-input instruction
2600       n->in(1)->outcnt() > 1 && // left use is NOT a last use
2601       (!n->in(1)->is_Phi() || n->in(1)->in(2) != n) && // it is not data loop
2602       n->in(2)->outcnt() == 1 &&// right use IS a last use
2603       !n->in(2)->is_Con() ) {   // right use is not a constant
2604     // Check for commutative opcode
2605     switch( nop ) {
2606     case Op_AddI:  case Op_AddF:  case Op_AddD:  case Op_AddL:
2607     case Op_MaxI:  case Op_MinI:
2608     case Op_MulI:  case Op_MulF:  case Op_MulD:  case Op_MulL:
2609     case Op_AndL:  case Op_XorL:  case Op_OrL:
2610     case Op_AndI:  case Op_XorI:  case Op_OrI: {
2611       // Move "last use" input to left by swapping inputs
2612       n->swap_edges(1, 2);
2613       break;
2614     }
2615     default:
2616       break;
2617     }
2618   }
2619 
2620 #ifdef ASSERT
2621   if( n->is_Mem() ) {
2622     int alias_idx = get_alias_index(n->as_Mem()->adr_type());
2623     assert( n->in(0) != NULL || alias_idx != Compile::AliasIdxRaw ||
2624             // oop will be recorded in oop map if load crosses safepoint
2625             n->is_Load() && (n->as_Load()->bottom_type()->isa_oopptr() ||
2626                              LoadNode::is_immutable_value(n->in(MemNode::Address))),
2627             "raw memory operations should have control edge");
2628   }
2629 #endif
2630   // Count FPU ops and common calls, implements item (3)
2631   switch( nop ) {
2632   // Count all float operations that may use FPU
2633   case Op_AddF:
2634   case Op_SubF:
2635   case Op_MulF:
2636   case Op_DivF:
2637   case Op_NegF:
2638   case Op_ModF:
2639   case Op_ConvI2F:
2640   case Op_ConF:
2641   case Op_CmpF:
2642   case Op_CmpF3:
2643   // case Op_ConvL2F: // longs are split into 32-bit halves
2644     frc.inc_float_count();
2645     break;
2646 
2647   case Op_ConvF2D:
2648   case Op_ConvD2F:
2649     frc.inc_float_count();
2650     frc.inc_double_count();
2651     break;
2652 
2653   // Count all double operations that may use FPU
2654   case Op_AddD:
2655   case Op_SubD:
2656   case Op_MulD:
2657   case Op_DivD:
2658   case Op_NegD:
2659   case Op_ModD:
2660   case Op_ConvI2D:
2661   case Op_ConvD2I:
2662   // case Op_ConvL2D: // handled by leaf call
2663   // case Op_ConvD2L: // handled by leaf call
2664   case Op_ConD:
2665   case Op_CmpD:
2666   case Op_CmpD3:
2667     frc.inc_double_count();
2668     break;
2669   case Op_Opaque1:              // Remove Opaque Nodes before matching
2670   case Op_Opaque2:              // Remove Opaque Nodes before matching
2671   case Op_Opaque3:
2672     n->subsume_by(n->in(1), this);
2673     break;
2674   case Op_CallStaticJava:
2675   case Op_CallJava:
2676   case Op_CallDynamicJava:
2677     frc.inc_java_call_count(); // Count java call site;
2678   case Op_CallRuntime:
2679   case Op_CallLeaf:
2680   case Op_CallLeafNoFP: {
2681     assert( n->is_Call(), "" );
2682     CallNode *call = n->as_Call();
2683     // Count call sites where the FP mode bit would have to be flipped.
2684     // Do not count uncommon runtime calls:
2685     // uncommon_trap, _complete_monitor_locking, _complete_monitor_unlocking,
2686     // _new_Java, _new_typeArray, _new_objArray, _rethrow_Java, ...
2687     if( !call->is_CallStaticJava() || !call->as_CallStaticJava()->_name ) {
2688       frc.inc_call_count();   // Count the call site
2689     } else {                  // See if uncommon argument is shared
2690       Node *n = call->in(TypeFunc::Parms);
2691       int nop = n->Opcode();
2692       // Clone shared simple arguments to uncommon calls, item (1).
2693       if( n->outcnt() > 1 &&
2694           !n->is_Proj() &&
2695           nop != Op_CreateEx &&
2696           nop != Op_CheckCastPP &&
2697           nop != Op_DecodeN &&
2698           nop != Op_DecodeNKlass &&
2699           !n->is_Mem() ) {
2700         Node *x = n->clone();
2701         call->set_req( TypeFunc::Parms, x );
2702       }
2703     }
2704     break;
2705   }
2706 
2707   case Op_StoreD:
2708   case Op_LoadD:
2709   case Op_LoadD_unaligned:
2710     frc.inc_double_count();
2711     goto handle_mem;
2712   case Op_StoreF:
2713   case Op_LoadF:
2714     frc.inc_float_count();
2715     goto handle_mem;
2716 
2717   case Op_StoreCM:
2718     {
2719       // Convert OopStore dependence into precedence edge
2720       Node* prec = n->in(MemNode::OopStore);
2721       n->del_req(MemNode::OopStore);
2722       n->add_prec(prec);
2723       eliminate_redundant_card_marks(n);
2724     }
2725 
2726     // fall through
2727 
2728   case Op_StoreB:
2729   case Op_StoreC:
2730   case Op_StorePConditional:
2731   case Op_StoreI:
2732   case Op_StoreL:
2733   case Op_StoreIConditional:
2734   case Op_StoreLConditional:
2735   case Op_CompareAndSwapI:
2736   case Op_CompareAndSwapL:
2737   case Op_CompareAndSwapP:
2738   case Op_CompareAndSwapN:
2739   case Op_GetAndAddI:
2740   case Op_GetAndAddL:
2741   case Op_GetAndSetI:
2742   case Op_GetAndSetL:
2743   case Op_GetAndSetP:
2744   case Op_GetAndSetN:
2745   case Op_StoreP:
2746   case Op_StoreN:
2747   case Op_StoreNKlass:
2748   case Op_LoadB:
2749   case Op_LoadUB:
2750   case Op_LoadUS:
2751   case Op_LoadI:
2752   case Op_LoadKlass:
2753   case Op_LoadNKlass:
2754   case Op_LoadL:
2755   case Op_LoadL_unaligned:
2756   case Op_LoadPLocked:
2757   case Op_LoadP:
2758   case Op_LoadN:
2759   case Op_LoadRange:
2760   case Op_LoadS: {
2761   handle_mem:
2762 #ifdef ASSERT
2763     if( VerifyOptoOopOffsets ) {
2764       assert( n->is_Mem(), "" );
2765       MemNode *mem  = (MemNode*)n;
2766       // Check to see if address types have grounded out somehow.
2767       const TypeInstPtr *tp = mem->in(MemNode::Address)->bottom_type()->isa_instptr();
2768       assert( !tp || oop_offset_is_sane(tp), "" );
2769     }
2770 #endif
2771     break;
2772   }
2773 
2774   case Op_AddP: {               // Assert sane base pointers
2775     Node *addp = n->in(AddPNode::Address);
2776     assert( !addp->is_AddP() ||
2777             addp->in(AddPNode::Base)->is_top() || // Top OK for allocation
2778             addp->in(AddPNode::Base) == n->in(AddPNode::Base),
2779             "Base pointers must match" );
2780 #ifdef _LP64
2781     if ((UseCompressedOops || UseCompressedClassPointers) &&
2782         addp->Opcode() == Op_ConP &&
2783         addp == n->in(AddPNode::Base) &&
2784         n->in(AddPNode::Offset)->is_Con()) {
2785       // Use addressing with narrow klass to load with offset on x86.
2786       // On sparc loading 32-bits constant and decoding it have less
2787       // instructions (4) then load 64-bits constant (7).
2788       // Do this transformation here since IGVN will convert ConN back to ConP.
2789       const Type* t = addp->bottom_type();
2790       if (t->isa_oopptr() || t->isa_klassptr()) {
2791         Node* nn = NULL;
2792 
2793         int op = t->isa_oopptr() ? Op_ConN : Op_ConNKlass;
2794 
2795         // Look for existing ConN node of the same exact type.
2796         Node* r  = root();
2797         uint cnt = r->outcnt();
2798         for (uint i = 0; i < cnt; i++) {
2799           Node* m = r->raw_out(i);
2800           if (m!= NULL && m->Opcode() == op &&
2801               m->bottom_type()->make_ptr() == t) {
2802             nn = m;
2803             break;
2804           }
2805         }
2806         if (nn != NULL) {
2807           // Decode a narrow oop to match address
2808           // [R12 + narrow_oop_reg<<3 + offset]
2809           if (t->isa_oopptr()) {
2810             nn = new (this) DecodeNNode(nn, t);
2811           } else {
2812             nn = new (this) DecodeNKlassNode(nn, t);
2813           }
2814           n->set_req(AddPNode::Base, nn);
2815           n->set_req(AddPNode::Address, nn);
2816           if (addp->outcnt() == 0) {
2817             addp->disconnect_inputs(NULL, this);
2818           }
2819         }
2820       }
2821     }
2822 #endif
2823     break;
2824   }
2825 
2826 #ifdef _LP64
2827   case Op_CastPP:
2828     if (n->in(1)->is_DecodeN() && Matcher::gen_narrow_oop_implicit_null_checks()) {
2829       Node* in1 = n->in(1);
2830       const Type* t = n->bottom_type();
2831       Node* new_in1 = in1->clone();
2832       new_in1->as_DecodeN()->set_type(t);
2833 
2834       if (!Matcher::narrow_oop_use_complex_address()) {
2835         //
2836         // x86, ARM and friends can handle 2 adds in addressing mode
2837         // and Matcher can fold a DecodeN node into address by using
2838         // a narrow oop directly and do implicit NULL check in address:
2839         //
2840         // [R12 + narrow_oop_reg<<3 + offset]
2841         // NullCheck narrow_oop_reg
2842         //
2843         // On other platforms (Sparc) we have to keep new DecodeN node and
2844         // use it to do implicit NULL check in address:
2845         //
2846         // decode_not_null narrow_oop_reg, base_reg
2847         // [base_reg + offset]
2848         // NullCheck base_reg
2849         //
2850         // Pin the new DecodeN node to non-null path on these platform (Sparc)
2851         // to keep the information to which NULL check the new DecodeN node
2852         // corresponds to use it as value in implicit_null_check().
2853         //
2854         new_in1->set_req(0, n->in(0));
2855       }
2856 
2857       n->subsume_by(new_in1, this);
2858       if (in1->outcnt() == 0) {
2859         in1->disconnect_inputs(NULL, this);
2860       }
2861     }
2862     break;
2863 
2864   case Op_CmpP:
2865     // Do this transformation here to preserve CmpPNode::sub() and
2866     // other TypePtr related Ideal optimizations (for example, ptr nullness).
2867     if (n->in(1)->is_DecodeNarrowPtr() || n->in(2)->is_DecodeNarrowPtr()) {
2868       Node* in1 = n->in(1);
2869       Node* in2 = n->in(2);
2870       if (!in1->is_DecodeNarrowPtr()) {
2871         in2 = in1;
2872         in1 = n->in(2);
2873       }
2874       assert(in1->is_DecodeNarrowPtr(), "sanity");
2875 
2876       Node* new_in2 = NULL;
2877       if (in2->is_DecodeNarrowPtr()) {
2878         assert(in2->Opcode() == in1->Opcode(), "must be same node type");
2879         new_in2 = in2->in(1);
2880       } else if (in2->Opcode() == Op_ConP) {
2881         const Type* t = in2->bottom_type();
2882         if (t == TypePtr::NULL_PTR) {
2883           assert(in1->is_DecodeN(), "compare klass to null?");
2884           // Don't convert CmpP null check into CmpN if compressed
2885           // oops implicit null check is not generated.
2886           // This will allow to generate normal oop implicit null check.
2887           if (Matcher::gen_narrow_oop_implicit_null_checks())
2888             new_in2 = ConNode::make(this, TypeNarrowOop::NULL_PTR);
2889           //
2890           // This transformation together with CastPP transformation above
2891           // will generated code for implicit NULL checks for compressed oops.
2892           //
2893           // The original code after Optimize()
2894           //
2895           //    LoadN memory, narrow_oop_reg
2896           //    decode narrow_oop_reg, base_reg
2897           //    CmpP base_reg, NULL
2898           //    CastPP base_reg // NotNull
2899           //    Load [base_reg + offset], val_reg
2900           //
2901           // after these transformations will be
2902           //
2903           //    LoadN memory, narrow_oop_reg
2904           //    CmpN narrow_oop_reg, NULL
2905           //    decode_not_null narrow_oop_reg, base_reg
2906           //    Load [base_reg + offset], val_reg
2907           //
2908           // and the uncommon path (== NULL) will use narrow_oop_reg directly
2909           // since narrow oops can be used in debug info now (see the code in
2910           // final_graph_reshaping_walk()).
2911           //
2912           // At the end the code will be matched to
2913           // on x86:
2914           //
2915           //    Load_narrow_oop memory, narrow_oop_reg
2916           //    Load [R12 + narrow_oop_reg<<3 + offset], val_reg
2917           //    NullCheck narrow_oop_reg
2918           //
2919           // and on sparc:
2920           //
2921           //    Load_narrow_oop memory, narrow_oop_reg
2922           //    decode_not_null narrow_oop_reg, base_reg
2923           //    Load [base_reg + offset], val_reg
2924           //    NullCheck base_reg
2925           //
2926         } else if (t->isa_oopptr()) {
2927           new_in2 = ConNode::make(this, t->make_narrowoop());
2928         } else if (t->isa_klassptr()) {
2929           new_in2 = ConNode::make(this, t->make_narrowklass());
2930         }
2931       }
2932       if (new_in2 != NULL) {
2933         Node* cmpN = new (this) CmpNNode(in1->in(1), new_in2);
2934         n->subsume_by(cmpN, this);
2935         if (in1->outcnt() == 0) {
2936           in1->disconnect_inputs(NULL, this);
2937         }
2938         if (in2->outcnt() == 0) {
2939           in2->disconnect_inputs(NULL, this);
2940         }
2941       }
2942     }
2943     break;
2944 
2945   case Op_DecodeN:
2946   case Op_DecodeNKlass:
2947     assert(!n->in(1)->is_EncodeNarrowPtr(), "should be optimized out");
2948     // DecodeN could be pinned when it can't be fold into
2949     // an address expression, see the code for Op_CastPP above.
2950     assert(n->in(0) == NULL || (UseCompressedOops && !Matcher::narrow_oop_use_complex_address()), "no control");
2951     break;
2952 
2953   case Op_EncodeP:
2954   case Op_EncodePKlass: {
2955     Node* in1 = n->in(1);
2956     if (in1->is_DecodeNarrowPtr()) {
2957       n->subsume_by(in1->in(1), this);
2958     } else if (in1->Opcode() == Op_ConP) {
2959       const Type* t = in1->bottom_type();
2960       if (t == TypePtr::NULL_PTR) {
2961         assert(t->isa_oopptr(), "null klass?");
2962         n->subsume_by(ConNode::make(this, TypeNarrowOop::NULL_PTR), this);
2963       } else if (t->isa_oopptr()) {
2964         n->subsume_by(ConNode::make(this, t->make_narrowoop()), this);
2965       } else if (t->isa_klassptr()) {
2966         n->subsume_by(ConNode::make(this, t->make_narrowklass()), this);
2967       }
2968     }
2969     if (in1->outcnt() == 0) {
2970       in1->disconnect_inputs(NULL, this);
2971     }
2972     break;
2973   }
2974 
2975   case Op_Proj: {
2976     if (OptimizeStringConcat) {
2977       ProjNode* p = n->as_Proj();
2978       if (p->_is_io_use) {
2979         // Separate projections were used for the exception path which
2980         // are normally removed by a late inline.  If it wasn't inlined
2981         // then they will hang around and should just be replaced with
2982         // the original one.
2983         Node* proj = NULL;
2984         // Replace with just one
2985         for (SimpleDUIterator i(p->in(0)); i.has_next(); i.next()) {
2986           Node *use = i.get();
2987           if (use->is_Proj() && p != use && use->as_Proj()->_con == p->_con) {
2988             proj = use;
2989             break;
2990           }
2991         }
2992         assert(proj != NULL, "must be found");
2993         p->subsume_by(proj, this);
2994       }
2995     }
2996     break;
2997   }
2998 
2999   case Op_Phi:
3000     if (n->as_Phi()->bottom_type()->isa_narrowoop() || n->as_Phi()->bottom_type()->isa_narrowklass()) {
3001       // The EncodeP optimization may create Phi with the same edges
3002       // for all paths. It is not handled well by Register Allocator.
3003       Node* unique_in = n->in(1);
3004       assert(unique_in != NULL, "");
3005       uint cnt = n->req();
3006       for (uint i = 2; i < cnt; i++) {
3007         Node* m = n->in(i);
3008         assert(m != NULL, "");
3009         if (unique_in != m)
3010           unique_in = NULL;
3011       }
3012       if (unique_in != NULL) {
3013         n->subsume_by(unique_in, this);
3014       }
3015     }
3016     break;
3017 
3018 #endif
3019 
3020 #ifdef ASSERT
3021   case Op_CastII:
3022     // Verify that all range check dependent CastII nodes were removed.
3023     if (n->isa_CastII()->has_range_check()) {
3024       n->dump(3);
3025       assert(false, "Range check dependent CastII node was not removed");
3026     }
3027     break;
3028 #endif
3029 
3030   case Op_ModI:
3031     if (UseDivMod) {
3032       // Check if a%b and a/b both exist
3033       Node* d = n->find_similar(Op_DivI);
3034       if (d) {
3035         // Replace them with a fused divmod if supported
3036         if (Matcher::has_match_rule(Op_DivModI)) {
3037           DivModINode* divmod = DivModINode::make(this, n);
3038           d->subsume_by(divmod->div_proj(), this);
3039           n->subsume_by(divmod->mod_proj(), this);
3040         } else {
3041           // replace a%b with a-((a/b)*b)
3042           Node* mult = new (this) MulINode(d, d->in(2));
3043           Node* sub  = new (this) SubINode(d->in(1), mult);
3044           n->subsume_by(sub, this);
3045         }
3046       }
3047     }
3048     break;
3049 
3050   case Op_ModL:
3051     if (UseDivMod) {
3052       // Check if a%b and a/b both exist
3053       Node* d = n->find_similar(Op_DivL);
3054       if (d) {
3055         // Replace them with a fused divmod if supported
3056         if (Matcher::has_match_rule(Op_DivModL)) {
3057           DivModLNode* divmod = DivModLNode::make(this, n);
3058           d->subsume_by(divmod->div_proj(), this);
3059           n->subsume_by(divmod->mod_proj(), this);
3060         } else {
3061           // replace a%b with a-((a/b)*b)
3062           Node* mult = new (this) MulLNode(d, d->in(2));
3063           Node* sub  = new (this) SubLNode(d->in(1), mult);
3064           n->subsume_by(sub, this);
3065         }
3066       }
3067     }
3068     break;
3069 
3070   case Op_LoadVector:
3071   case Op_StoreVector:
3072     break;
3073 
3074   case Op_PackB:
3075   case Op_PackS:
3076   case Op_PackI:
3077   case Op_PackF:
3078   case Op_PackL:
3079   case Op_PackD:
3080     if (n->req()-1 > 2) {
3081       // Replace many operand PackNodes with a binary tree for matching
3082       PackNode* p = (PackNode*) n;
3083       Node* btp = p->binary_tree_pack(this, 1, n->req());
3084       n->subsume_by(btp, this);
3085     }
3086     break;
3087   case Op_Loop:
3088   case Op_CountedLoop:
3089     if (n->as_Loop()->is_inner_loop()) {
3090       frc.inc_inner_loop_count();
3091     }
3092     break;
3093   case Op_LShiftI:
3094   case Op_RShiftI:
3095   case Op_URShiftI:
3096   case Op_LShiftL:
3097   case Op_RShiftL:
3098   case Op_URShiftL:
3099     if (Matcher::need_masked_shift_count) {
3100       // The cpu's shift instructions don't restrict the count to the
3101       // lower 5/6 bits. We need to do the masking ourselves.
3102       Node* in2 = n->in(2);
3103       juint mask = (n->bottom_type() == TypeInt::INT) ? (BitsPerInt - 1) : (BitsPerLong - 1);
3104       const TypeInt* t = in2->find_int_type();
3105       if (t != NULL && t->is_con()) {
3106         juint shift = t->get_con();
3107         if (shift > mask) { // Unsigned cmp
3108           n->set_req(2, ConNode::make(this, TypeInt::make(shift & mask)));
3109         }
3110       } else {
3111         if (t == NULL || t->_lo < 0 || t->_hi > (int)mask) {
3112           Node* shift = new (this) AndINode(in2, ConNode::make(this, TypeInt::make(mask)));
3113           n->set_req(2, shift);
3114         }
3115       }
3116       if (in2->outcnt() == 0) { // Remove dead node
3117         in2->disconnect_inputs(NULL, this);
3118       }
3119     }
3120     break;
3121   case Op_MemBarStoreStore:
3122   case Op_MemBarRelease:
3123     // Break the link with AllocateNode: it is no longer useful and
3124     // confuses register allocation.
3125     if (n->req() > MemBarNode::Precedent) {
3126       n->set_req(MemBarNode::Precedent, top());
3127     }
3128     break;
3129   default:
3130     assert( !n->is_Call(), "" );
3131     assert( !n->is_Mem(), "" );
3132     assert( nop != Op_ProfileBoolean, "should be eliminated during IGVN");
3133     break;
3134   }
3135 
3136   // Collect CFG split points
3137   if (n->is_MultiBranch())
3138     frc._tests.push(n);
3139 }
3140 
3141 //------------------------------final_graph_reshaping_walk---------------------
3142 // Replacing Opaque nodes with their input in final_graph_reshaping_impl(),
3143 // requires that the walk visits a node's inputs before visiting the node.
3144 void Compile::final_graph_reshaping_walk( Node_Stack &nstack, Node *root, Final_Reshape_Counts &frc ) {
3145   ResourceArea *area = Thread::current()->resource_area();
3146   Unique_Node_List sfpt(area);
3147 
3148   frc._visited.set(root->_idx); // first, mark node as visited
3149   uint cnt = root->req();
3150   Node *n = root;
3151   uint  i = 0;
3152   while (true) {
3153     if (i < cnt) {
3154       // Place all non-visited non-null inputs onto stack
3155       Node* m = n->in(i);
3156       ++i;
3157       if (m != NULL && !frc._visited.test_set(m->_idx)) {
3158         if (m->is_SafePoint() && m->as_SafePoint()->jvms() != NULL) {
3159           // compute worst case interpreter size in case of a deoptimization
3160           update_interpreter_frame_size(m->as_SafePoint()->jvms()->interpreter_frame_size());
3161 
3162           sfpt.push(m);
3163         }
3164         cnt = m->req();
3165         nstack.push(n, i); // put on stack parent and next input's index
3166         n = m;
3167         i = 0;
3168       }
3169     } else {
3170       // Now do post-visit work
3171       final_graph_reshaping_impl( n, frc );
3172       if (nstack.is_empty())
3173         break;             // finished
3174       n = nstack.node();   // Get node from stack
3175       cnt = n->req();
3176       i = nstack.index();
3177       nstack.pop();        // Shift to the next node on stack
3178     }
3179   }
3180 
3181   // Skip next transformation if compressed oops are not used.
3182   if ((UseCompressedOops && !Matcher::gen_narrow_oop_implicit_null_checks()) ||
3183       (!UseCompressedOops && !UseCompressedClassPointers))
3184     return;
3185 
3186   // Go over safepoints nodes to skip DecodeN/DecodeNKlass nodes for debug edges.
3187   // It could be done for an uncommon traps or any safepoints/calls
3188   // if the DecodeN/DecodeNKlass node is referenced only in a debug info.
3189   while (sfpt.size() > 0) {
3190     n = sfpt.pop();
3191     JVMState *jvms = n->as_SafePoint()->jvms();
3192     assert(jvms != NULL, "sanity");
3193     int start = jvms->debug_start();
3194     int end   = n->req();
3195     bool is_uncommon = (n->is_CallStaticJava() &&
3196                         n->as_CallStaticJava()->uncommon_trap_request() != 0);
3197     for (int j = start; j < end; j++) {
3198       Node* in = n->in(j);
3199       if (in->is_DecodeNarrowPtr()) {
3200         bool safe_to_skip = true;
3201         if (!is_uncommon ) {
3202           // Is it safe to skip?
3203           for (uint i = 0; i < in->outcnt(); i++) {
3204             Node* u = in->raw_out(i);
3205             if (!u->is_SafePoint() ||
3206                  u->is_Call() && u->as_Call()->has_non_debug_use(n)) {
3207               safe_to_skip = false;
3208             }
3209           }
3210         }
3211         if (safe_to_skip) {
3212           n->set_req(j, in->in(1));
3213         }
3214         if (in->outcnt() == 0) {
3215           in->disconnect_inputs(NULL, this);
3216         }
3217       }
3218     }
3219   }
3220 }
3221 
3222 //------------------------------final_graph_reshaping--------------------------
3223 // Final Graph Reshaping.
3224 //
3225 // (1) Clone simple inputs to uncommon calls, so they can be scheduled late
3226 //     and not commoned up and forced early.  Must come after regular
3227 //     optimizations to avoid GVN undoing the cloning.  Clone constant
3228 //     inputs to Loop Phis; these will be split by the allocator anyways.
3229 //     Remove Opaque nodes.
3230 // (2) Move last-uses by commutative operations to the left input to encourage
3231 //     Intel update-in-place two-address operations and better register usage
3232 //     on RISCs.  Must come after regular optimizations to avoid GVN Ideal
3233 //     calls canonicalizing them back.
3234 // (3) Count the number of double-precision FP ops, single-precision FP ops
3235 //     and call sites.  On Intel, we can get correct rounding either by
3236 //     forcing singles to memory (requires extra stores and loads after each
3237 //     FP bytecode) or we can set a rounding mode bit (requires setting and
3238 //     clearing the mode bit around call sites).  The mode bit is only used
3239 //     if the relative frequency of single FP ops to calls is low enough.
3240 //     This is a key transform for SPEC mpeg_audio.
3241 // (4) Detect infinite loops; blobs of code reachable from above but not
3242 //     below.  Several of the Code_Gen algorithms fail on such code shapes,
3243 //     so we simply bail out.  Happens a lot in ZKM.jar, but also happens
3244 //     from time to time in other codes (such as -Xcomp finalizer loops, etc).
3245 //     Detection is by looking for IfNodes where only 1 projection is
3246 //     reachable from below or CatchNodes missing some targets.
3247 // (5) Assert for insane oop offsets in debug mode.
3248 
3249 bool Compile::final_graph_reshaping() {
3250   // an infinite loop may have been eliminated by the optimizer,
3251   // in which case the graph will be empty.
3252   if (root()->req() == 1) {
3253     record_method_not_compilable("trivial infinite loop");
3254     return true;
3255   }
3256 
3257   // Expensive nodes have their control input set to prevent the GVN
3258   // from freely commoning them. There's no GVN beyond this point so
3259   // no need to keep the control input. We want the expensive nodes to
3260   // be freely moved to the least frequent code path by gcm.
3261   assert(OptimizeExpensiveOps || expensive_count() == 0, "optimization off but list non empty?");
3262   for (int i = 0; i < expensive_count(); i++) {
3263     _expensive_nodes->at(i)->set_req(0, NULL);
3264   }
3265 
3266   Final_Reshape_Counts frc;
3267 
3268   // Visit everybody reachable!
3269   // Allocate stack of size C->live_nodes()/2 to avoid frequent realloc
3270   Node_Stack nstack(live_nodes() >> 1);
3271   final_graph_reshaping_walk(nstack, root(), frc);
3272 
3273   // Check for unreachable (from below) code (i.e., infinite loops).
3274   for( uint i = 0; i < frc._tests.size(); i++ ) {
3275     MultiBranchNode *n = frc._tests[i]->as_MultiBranch();
3276     // Get number of CFG targets.
3277     // Note that PCTables include exception targets after calls.
3278     uint required_outcnt = n->required_outcnt();
3279     if (n->outcnt() != required_outcnt) {
3280       // Check for a few special cases.  Rethrow Nodes never take the
3281       // 'fall-thru' path, so expected kids is 1 less.
3282       if (n->is_PCTable() && n->in(0) && n->in(0)->in(0)) {
3283         if (n->in(0)->in(0)->is_Call()) {
3284           CallNode *call = n->in(0)->in(0)->as_Call();
3285           if (call->entry_point() == OptoRuntime::rethrow_stub()) {
3286             required_outcnt--;      // Rethrow always has 1 less kid
3287           } else if (call->req() > TypeFunc::Parms &&
3288                      call->is_CallDynamicJava()) {
3289             // Check for null receiver. In such case, the optimizer has
3290             // detected that the virtual call will always result in a null
3291             // pointer exception. The fall-through projection of this CatchNode
3292             // will not be populated.
3293             Node *arg0 = call->in(TypeFunc::Parms);
3294             if (arg0->is_Type() &&
3295                 arg0->as_Type()->type()->higher_equal(TypePtr::NULL_PTR)) {
3296               required_outcnt--;
3297             }
3298           } else if (call->entry_point() == OptoRuntime::new_array_Java() &&
3299                      call->req() > TypeFunc::Parms+1 &&
3300                      call->is_CallStaticJava()) {
3301             // Check for negative array length. In such case, the optimizer has
3302             // detected that the allocation attempt will always result in an
3303             // exception. There is no fall-through projection of this CatchNode .
3304             Node *arg1 = call->in(TypeFunc::Parms+1);
3305             if (arg1->is_Type() &&
3306                 arg1->as_Type()->type()->join(TypeInt::POS)->empty()) {
3307               required_outcnt--;
3308             }
3309           }
3310         }
3311       }
3312       // Recheck with a better notion of 'required_outcnt'
3313       if (n->outcnt() != required_outcnt) {
3314         record_method_not_compilable("malformed control flow");
3315         return true;            // Not all targets reachable!
3316       }
3317     }
3318     // Check that I actually visited all kids.  Unreached kids
3319     // must be infinite loops.
3320     for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++)
3321       if (!frc._visited.test(n->fast_out(j)->_idx)) {
3322         record_method_not_compilable("infinite loop");
3323         return true;            // Found unvisited kid; must be unreach
3324       }
3325   }
3326 
3327   // If original bytecodes contained a mixture of floats and doubles
3328   // check if the optimizer has made it homogenous, item (3).
3329   if( Use24BitFPMode && Use24BitFP && UseSSE == 0 &&
3330       frc.get_float_count() > 32 &&
3331       frc.get_double_count() == 0 &&
3332       (10 * frc.get_call_count() < frc.get_float_count()) ) {
3333     set_24_bit_selection_and_mode( false,  true );
3334   }
3335 
3336   set_java_calls(frc.get_java_call_count());
3337   set_inner_loops(frc.get_inner_loop_count());
3338 
3339   // No infinite loops, no reason to bail out.
3340   return false;
3341 }
3342 
3343 //-----------------------------too_many_traps----------------------------------
3344 // Report if there are too many traps at the current method and bci.
3345 // Return true if there was a trap, and/or PerMethodTrapLimit is exceeded.
3346 bool Compile::too_many_traps(ciMethod* method,
3347                              int bci,
3348                              Deoptimization::DeoptReason reason) {
3349   ciMethodData* md = method->method_data();
3350   if (md->is_empty()) {
3351     // Assume the trap has not occurred, or that it occurred only
3352     // because of a transient condition during start-up in the interpreter.
3353     return false;
3354   }
3355   ciMethod* m = Deoptimization::reason_is_speculate(reason) ? this->method() : NULL;
3356   if (md->has_trap_at(bci, m, reason) != 0) {
3357     // Assume PerBytecodeTrapLimit==0, for a more conservative heuristic.
3358     // Also, if there are multiple reasons, or if there is no per-BCI record,
3359     // assume the worst.
3360     if (log())
3361       log()->elem("observe trap='%s' count='%d'",
3362                   Deoptimization::trap_reason_name(reason),
3363                   md->trap_count(reason));
3364     return true;
3365   } else {
3366     // Ignore method/bci and see if there have been too many globally.
3367     return too_many_traps(reason, md);
3368   }
3369 }
3370 
3371 // Less-accurate variant which does not require a method and bci.
3372 bool Compile::too_many_traps(Deoptimization::DeoptReason reason,
3373                              ciMethodData* logmd) {
3374   if (trap_count(reason) >= Deoptimization::per_method_trap_limit(reason)) {
3375     // Too many traps globally.
3376     // Note that we use cumulative trap_count, not just md->trap_count.
3377     if (log()) {
3378       int mcount = (logmd == NULL)? -1: (int)logmd->trap_count(reason);
3379       log()->elem("observe trap='%s' count='0' mcount='%d' ccount='%d'",
3380                   Deoptimization::trap_reason_name(reason),
3381                   mcount, trap_count(reason));
3382     }
3383     return true;
3384   } else {
3385     // The coast is clear.
3386     return false;
3387   }
3388 }
3389 
3390 //--------------------------too_many_recompiles--------------------------------
3391 // Report if there are too many recompiles at the current method and bci.
3392 // Consults PerBytecodeRecompilationCutoff and PerMethodRecompilationCutoff.
3393 // Is not eager to return true, since this will cause the compiler to use
3394 // Action_none for a trap point, to avoid too many recompilations.
3395 bool Compile::too_many_recompiles(ciMethod* method,
3396                                   int bci,
3397                                   Deoptimization::DeoptReason reason) {
3398   ciMethodData* md = method->method_data();
3399   if (md->is_empty()) {
3400     // Assume the trap has not occurred, or that it occurred only
3401     // because of a transient condition during start-up in the interpreter.
3402     return false;
3403   }
3404   // Pick a cutoff point well within PerBytecodeRecompilationCutoff.
3405   uint bc_cutoff = (uint) PerBytecodeRecompilationCutoff / 8;
3406   uint m_cutoff  = (uint) PerMethodRecompilationCutoff / 2 + 1;  // not zero
3407   Deoptimization::DeoptReason per_bc_reason
3408     = Deoptimization::reason_recorded_per_bytecode_if_any(reason);
3409   ciMethod* m = Deoptimization::reason_is_speculate(reason) ? this->method() : NULL;
3410   if ((per_bc_reason == Deoptimization::Reason_none
3411        || md->has_trap_at(bci, m, reason) != 0)
3412       // The trap frequency measure we care about is the recompile count:
3413       && md->trap_recompiled_at(bci, m)
3414       && md->overflow_recompile_count() >= bc_cutoff) {
3415     // Do not emit a trap here if it has already caused recompilations.
3416     // Also, if there are multiple reasons, or if there is no per-BCI record,
3417     // assume the worst.
3418     if (log())
3419       log()->elem("observe trap='%s recompiled' count='%d' recompiles2='%d'",
3420                   Deoptimization::trap_reason_name(reason),
3421                   md->trap_count(reason),
3422                   md->overflow_recompile_count());
3423     return true;
3424   } else if (trap_count(reason) != 0
3425              && decompile_count() >= m_cutoff) {
3426     // Too many recompiles globally, and we have seen this sort of trap.
3427     // Use cumulative decompile_count, not just md->decompile_count.
3428     if (log())
3429       log()->elem("observe trap='%s' count='%d' mcount='%d' decompiles='%d' mdecompiles='%d'",
3430                   Deoptimization::trap_reason_name(reason),
3431                   md->trap_count(reason), trap_count(reason),
3432                   md->decompile_count(), decompile_count());
3433     return true;
3434   } else {
3435     // The coast is clear.
3436     return false;
3437   }
3438 }
3439 
3440 // Compute when not to trap. Used by matching trap based nodes and
3441 // NullCheck optimization.
3442 void Compile::set_allowed_deopt_reasons() {
3443   _allowed_reasons = 0;
3444   if (is_method_compilation()) {
3445     for (int rs = (int)Deoptimization::Reason_none+1; rs < Compile::trapHistLength; rs++) {
3446       assert(rs < BitsPerInt, "recode bit map");
3447       if (!too_many_traps((Deoptimization::DeoptReason) rs)) {
3448         _allowed_reasons |= nth_bit(rs);
3449       }
3450     }
3451   }
3452 }
3453 
3454 #ifndef PRODUCT
3455 //------------------------------verify_graph_edges---------------------------
3456 // Walk the Graph and verify that there is a one-to-one correspondence
3457 // between Use-Def edges and Def-Use edges in the graph.
3458 void Compile::verify_graph_edges(bool no_dead_code) {
3459   if (VerifyGraphEdges) {
3460     ResourceArea *area = Thread::current()->resource_area();
3461     Unique_Node_List visited(area);
3462     // Call recursive graph walk to check edges
3463     _root->verify_edges(visited);
3464     if (no_dead_code) {
3465       // Now make sure that no visited node is used by an unvisited node.
3466       bool dead_nodes = 0;
3467       Unique_Node_List checked(area);
3468       while (visited.size() > 0) {
3469         Node* n = visited.pop();
3470         checked.push(n);
3471         for (uint i = 0; i < n->outcnt(); i++) {
3472           Node* use = n->raw_out(i);
3473           if (checked.member(use))  continue;  // already checked
3474           if (visited.member(use))  continue;  // already in the graph
3475           if (use->is_Con())        continue;  // a dead ConNode is OK
3476           // At this point, we have found a dead node which is DU-reachable.
3477           if (dead_nodes++ == 0)
3478             tty->print_cr("*** Dead nodes reachable via DU edges:");
3479           use->dump(2);
3480           tty->print_cr("---");
3481           checked.push(use);  // No repeats; pretend it is now checked.
3482         }
3483       }
3484       assert(dead_nodes == 0, "using nodes must be reachable from root");
3485     }
3486   }
3487 }
3488 
3489 // Verify GC barriers consistency
3490 // Currently supported:
3491 // - G1 pre-barriers (see GraphKit::g1_write_barrier_pre())
3492 void Compile::verify_barriers() {
3493   if (UseG1GC) {
3494     // Verify G1 pre-barriers
3495     const int marking_offset = in_bytes(JavaThread::satb_mark_queue_offset() + PtrQueue::byte_offset_of_active());
3496 
3497     ResourceArea *area = Thread::current()->resource_area();
3498     Unique_Node_List visited(area);
3499     Node_List worklist(area);
3500     // We're going to walk control flow backwards starting from the Root
3501     worklist.push(_root);
3502     while (worklist.size() > 0) {
3503       Node* x = worklist.pop();
3504       if (x == NULL || x == top()) continue;
3505       if (visited.member(x)) {
3506         continue;
3507       } else {
3508         visited.push(x);
3509       }
3510 
3511       if (x->is_Region()) {
3512         for (uint i = 1; i < x->req(); i++) {
3513           worklist.push(x->in(i));
3514         }
3515       } else {
3516         worklist.push(x->in(0));
3517         // We are looking for the pattern:
3518         //                            /->ThreadLocal
3519         // If->Bool->CmpI->LoadB->AddP->ConL(marking_offset)
3520         //              \->ConI(0)
3521         // We want to verify that the If and the LoadB have the same control
3522         // See GraphKit::g1_write_barrier_pre()
3523         if (x->is_If()) {
3524           IfNode *iff = x->as_If();
3525           if (iff->in(1)->is_Bool() && iff->in(1)->in(1)->is_Cmp()) {
3526             CmpNode *cmp = iff->in(1)->in(1)->as_Cmp();
3527             if (cmp->Opcode() == Op_CmpI && cmp->in(2)->is_Con() && cmp->in(2)->bottom_type()->is_int()->get_con() == 0
3528                 && cmp->in(1)->is_Load()) {
3529               LoadNode* load = cmp->in(1)->as_Load();
3530               if (load->Opcode() == Op_LoadB && load->in(2)->is_AddP() && load->in(2)->in(2)->Opcode() == Op_ThreadLocal
3531                   && load->in(2)->in(3)->is_Con()
3532                   && load->in(2)->in(3)->bottom_type()->is_intptr_t()->get_con() == marking_offset) {
3533 
3534                 Node* if_ctrl = iff->in(0);
3535                 Node* load_ctrl = load->in(0);
3536 
3537                 if (if_ctrl != load_ctrl) {
3538                   // Skip possible CProj->NeverBranch in infinite loops
3539                   if ((if_ctrl->is_Proj() && if_ctrl->Opcode() == Op_CProj)
3540                       && (if_ctrl->in(0)->is_MultiBranch() && if_ctrl->in(0)->Opcode() == Op_NeverBranch)) {
3541                     if_ctrl = if_ctrl->in(0)->in(0);
3542                   }
3543                 }
3544                 assert(load_ctrl != NULL && if_ctrl == load_ctrl, "controls must match");
3545               }
3546             }
3547           }
3548         }
3549       }
3550     }
3551   }
3552 }
3553 
3554 #endif
3555 
3556 // The Compile object keeps track of failure reasons separately from the ciEnv.
3557 // This is required because there is not quite a 1-1 relation between the
3558 // ciEnv and its compilation task and the Compile object.  Note that one
3559 // ciEnv might use two Compile objects, if C2Compiler::compile_method decides
3560 // to backtrack and retry without subsuming loads.  Other than this backtracking
3561 // behavior, the Compile's failure reason is quietly copied up to the ciEnv
3562 // by the logic in C2Compiler.
3563 void Compile::record_failure(const char* reason) {
3564   if (log() != NULL) {
3565     log()->elem("failure reason='%s' phase='compile'", reason);
3566   }
3567   if (_failure_reason == NULL) {
3568     // Record the first failure reason.
3569     _failure_reason = reason;
3570   }
3571 
3572   EventCompilerFailure event;
3573   if (event.should_commit()) {
3574     event.set_compileID(Compile::compile_id());
3575     event.set_failure(reason);
3576     event.commit();
3577   }
3578 
3579   if (!C->failure_reason_is(C2Compiler::retry_no_subsuming_loads())) {
3580     C->print_method(PHASE_FAILURE);
3581   }
3582   _root = NULL;  // flush the graph, too
3583 }
3584 
3585 Compile::TracePhase::TracePhase(const char* name, elapsedTimer* accumulator, bool dolog)
3586   : TraceTime(NULL, accumulator, false NOT_PRODUCT( || TimeCompiler ), false),
3587     _phase_name(name), _dolog(dolog)
3588 {
3589   if (dolog) {
3590     C = Compile::current();
3591     _log = C->log();
3592   } else {
3593     C = NULL;
3594     _log = NULL;
3595   }
3596   if (_log != NULL) {
3597     _log->begin_head("phase name='%s' nodes='%d' live='%d'", _phase_name, C->unique(), C->live_nodes());
3598     _log->stamp();
3599     _log->end_head();
3600   }
3601 }
3602 
3603 Compile::TracePhase::~TracePhase() {
3604 
3605   C = Compile::current();
3606   if (_dolog) {
3607     _log = C->log();
3608   } else {
3609     _log = NULL;
3610   }
3611 
3612 #ifdef ASSERT
3613   if (PrintIdealNodeCount) {
3614     tty->print_cr("phase name='%s' nodes='%d' live='%d' live_graph_walk='%d'",
3615                   _phase_name, C->unique(), C->live_nodes(), C->count_live_nodes_by_graph_walk());
3616   }
3617 
3618   if (VerifyIdealNodeCount) {
3619     Compile::current()->print_missing_nodes();
3620   }
3621 #endif
3622 
3623   if (_log != NULL) {
3624     _log->done("phase name='%s' nodes='%d' live='%d'", _phase_name, C->unique(), C->live_nodes());
3625   }
3626 }
3627 
3628 //=============================================================================
3629 // Two Constant's are equal when the type and the value are equal.
3630 bool Compile::Constant::operator==(const Constant& other) {
3631   if (type()          != other.type()         )  return false;
3632   if (can_be_reused() != other.can_be_reused())  return false;
3633   // For floating point values we compare the bit pattern.
3634   switch (type()) {
3635   case T_FLOAT:   return (_v._value.i == other._v._value.i);
3636   case T_LONG:
3637   case T_DOUBLE:  return (_v._value.j == other._v._value.j);
3638   case T_OBJECT:
3639   case T_ADDRESS: return (_v._value.l == other._v._value.l);
3640   case T_VOID:    return (_v._value.l == other._v._value.l);  // jump-table entries
3641   case T_METADATA: return (_v._metadata == other._v._metadata);
3642   default: ShouldNotReachHere();
3643   }
3644   return false;
3645 }
3646 
3647 static int type_to_size_in_bytes(BasicType t) {
3648   switch (t) {
3649   case T_LONG:    return sizeof(jlong  );
3650   case T_FLOAT:   return sizeof(jfloat );
3651   case T_DOUBLE:  return sizeof(jdouble);
3652   case T_METADATA: return sizeof(Metadata*);
3653     // We use T_VOID as marker for jump-table entries (labels) which
3654     // need an internal word relocation.
3655   case T_VOID:
3656   case T_ADDRESS:
3657   case T_OBJECT:  return sizeof(jobject);
3658   }
3659 
3660   ShouldNotReachHere();
3661   return -1;
3662 }
3663 
3664 int Compile::ConstantTable::qsort_comparator(Constant* a, Constant* b) {
3665   // sort descending
3666   if (a->freq() > b->freq())  return -1;
3667   if (a->freq() < b->freq())  return  1;
3668   return 0;
3669 }
3670 
3671 void Compile::ConstantTable::calculate_offsets_and_size() {
3672   // First, sort the array by frequencies.
3673   _constants.sort(qsort_comparator);
3674 
3675 #ifdef ASSERT
3676   // Make sure all jump-table entries were sorted to the end of the
3677   // array (they have a negative frequency).
3678   bool found_void = false;
3679   for (int i = 0; i < _constants.length(); i++) {
3680     Constant con = _constants.at(i);
3681     if (con.type() == T_VOID)
3682       found_void = true;  // jump-tables
3683     else
3684       assert(!found_void, "wrong sorting");
3685   }
3686 #endif
3687 
3688   int offset = 0;
3689   for (int i = 0; i < _constants.length(); i++) {
3690     Constant* con = _constants.adr_at(i);
3691 
3692     // Align offset for type.
3693     int typesize = type_to_size_in_bytes(con->type());
3694     offset = align_size_up(offset, typesize);
3695     con->set_offset(offset);   // set constant's offset
3696 
3697     if (con->type() == T_VOID) {
3698       MachConstantNode* n = (MachConstantNode*) con->get_jobject();
3699       offset = offset + typesize * n->outcnt();  // expand jump-table
3700     } else {
3701       offset = offset + typesize;
3702     }
3703   }
3704 
3705   // Align size up to the next section start (which is insts; see
3706   // CodeBuffer::align_at_start).
3707   assert(_size == -1, "already set?");
3708   _size = align_size_up(offset, CodeEntryAlignment);
3709 }
3710 
3711 void Compile::ConstantTable::emit(CodeBuffer& cb) {
3712   MacroAssembler _masm(&cb);
3713   for (int i = 0; i < _constants.length(); i++) {
3714     Constant con = _constants.at(i);
3715     address constant_addr = NULL;
3716     switch (con.type()) {
3717     case T_LONG:   constant_addr = _masm.long_constant(  con.get_jlong()  ); break;
3718     case T_FLOAT:  constant_addr = _masm.float_constant( con.get_jfloat() ); break;
3719     case T_DOUBLE: constant_addr = _masm.double_constant(con.get_jdouble()); break;
3720     case T_OBJECT: {
3721       jobject obj = con.get_jobject();
3722       int oop_index = _masm.oop_recorder()->find_index(obj);
3723       constant_addr = _masm.address_constant((address) obj, oop_Relocation::spec(oop_index));
3724       break;
3725     }
3726     case T_ADDRESS: {
3727       address addr = (address) con.get_jobject();
3728       constant_addr = _masm.address_constant(addr);
3729       break;
3730     }
3731     // We use T_VOID as marker for jump-table entries (labels) which
3732     // need an internal word relocation.
3733     case T_VOID: {
3734       MachConstantNode* n = (MachConstantNode*) con.get_jobject();
3735       // Fill the jump-table with a dummy word.  The real value is
3736       // filled in later in fill_jump_table.
3737       address dummy = (address) n;
3738       constant_addr = _masm.address_constant(dummy);
3739       // Expand jump-table
3740       for (uint i = 1; i < n->outcnt(); i++) {
3741         address temp_addr = _masm.address_constant(dummy + i);
3742         assert(temp_addr, "consts section too small");
3743       }
3744       break;
3745     }
3746     case T_METADATA: {
3747       Metadata* obj = con.get_metadata();
3748       int metadata_index = _masm.oop_recorder()->find_index(obj);
3749       constant_addr = _masm.address_constant((address) obj, metadata_Relocation::spec(metadata_index));
3750       break;
3751     }
3752     default: ShouldNotReachHere();
3753     }
3754     assert(constant_addr, "consts section too small");
3755     assert((constant_addr - _masm.code()->consts()->start()) == con.offset(),
3756             err_msg_res("must be: %d == %d", (int) (constant_addr - _masm.code()->consts()->start()), (int)(con.offset())));
3757   }
3758 }
3759 
3760 int Compile::ConstantTable::find_offset(Constant& con) const {
3761   int idx = _constants.find(con);
3762   assert(idx != -1, "constant must be in constant table");
3763   int offset = _constants.at(idx).offset();
3764   assert(offset != -1, "constant table not emitted yet?");
3765   return offset;
3766 }
3767 
3768 void Compile::ConstantTable::add(Constant& con) {
3769   if (con.can_be_reused()) {
3770     int idx = _constants.find(con);
3771     if (idx != -1 && _constants.at(idx).can_be_reused()) {
3772       _constants.adr_at(idx)->inc_freq(con.freq());  // increase the frequency by the current value
3773       return;
3774     }
3775   }
3776   (void) _constants.append(con);
3777 }
3778 
3779 Compile::Constant Compile::ConstantTable::add(MachConstantNode* n, BasicType type, jvalue value) {
3780   Block* b = Compile::current()->cfg()->get_block_for_node(n);
3781   Constant con(type, value, b->_freq);
3782   add(con);
3783   return con;
3784 }
3785 
3786 Compile::Constant Compile::ConstantTable::add(Metadata* metadata) {
3787   Constant con(metadata);
3788   add(con);
3789   return con;
3790 }
3791 
3792 Compile::Constant Compile::ConstantTable::add(MachConstantNode* n, MachOper* oper) {
3793   jvalue value;
3794   BasicType type = oper->type()->basic_type();
3795   switch (type) {
3796   case T_LONG:    value.j = oper->constantL(); break;
3797   case T_FLOAT:   value.f = oper->constantF(); break;
3798   case T_DOUBLE:  value.d = oper->constantD(); break;
3799   case T_OBJECT:
3800   case T_ADDRESS: value.l = (jobject) oper->constant(); break;
3801   case T_METADATA: return add((Metadata*)oper->constant()); break;
3802   default: guarantee(false, err_msg_res("unhandled type: %s", type2name(type)));
3803   }
3804   return add(n, type, value);
3805 }
3806 
3807 Compile::Constant Compile::ConstantTable::add_jump_table(MachConstantNode* n) {
3808   jvalue value;
3809   // We can use the node pointer here to identify the right jump-table
3810   // as this method is called from Compile::Fill_buffer right before
3811   // the MachNodes are emitted and the jump-table is filled (means the
3812   // MachNode pointers do not change anymore).
3813   value.l = (jobject) n;
3814   Constant con(T_VOID, value, next_jump_table_freq(), false);  // Labels of a jump-table cannot be reused.
3815   add(con);
3816   return con;
3817 }
3818 
3819 void Compile::ConstantTable::fill_jump_table(CodeBuffer& cb, MachConstantNode* n, GrowableArray<Label*> labels) const {
3820   // If called from Compile::scratch_emit_size do nothing.
3821   if (Compile::current()->in_scratch_emit_size())  return;
3822 
3823   assert(labels.is_nonempty(), "must be");
3824   assert((uint) labels.length() == n->outcnt(), err_msg_res("must be equal: %d == %d", labels.length(), n->outcnt()));
3825 
3826   // Since MachConstantNode::constant_offset() also contains
3827   // table_base_offset() we need to subtract the table_base_offset()
3828   // to get the plain offset into the constant table.
3829   int offset = n->constant_offset() - table_base_offset();
3830 
3831   MacroAssembler _masm(&cb);
3832   address* jump_table_base = (address*) (_masm.code()->consts()->start() + offset);
3833 
3834   for (uint i = 0; i < n->outcnt(); i++) {
3835     address* constant_addr = &jump_table_base[i];
3836     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)));
3837     *constant_addr = cb.consts()->target(*labels.at(i), (address) constant_addr);
3838     cb.consts()->relocate((address) constant_addr, relocInfo::internal_word_type);
3839   }
3840 }
3841 
3842 void Compile::dump_inlining() {
3843   if (print_inlining() || print_intrinsics()) {
3844     // Print inlining message for candidates that we couldn't inline
3845     // for lack of space or non constant receiver
3846     for (int i = 0; i < _late_inlines.length(); i++) {
3847       CallGenerator* cg = _late_inlines.at(i);
3848       cg->print_inlining_late("live nodes > LiveNodeCountInliningCutoff");
3849     }
3850     Unique_Node_List useful;
3851     useful.push(root());
3852     for (uint next = 0; next < useful.size(); ++next) {
3853       Node* n  = useful.at(next);
3854       if (n->is_Call() && n->as_Call()->generator() != NULL && n->as_Call()->generator()->call_node() == n) {
3855         CallNode* call = n->as_Call();
3856         CallGenerator* cg = call->generator();
3857         cg->print_inlining_late("receiver not constant");
3858       }
3859       uint max = n->len();
3860       for ( uint i = 0; i < max; ++i ) {
3861         Node *m = n->in(i);
3862         if ( m == NULL ) continue;
3863         useful.push(m);
3864       }
3865     }
3866     for (int i = 0; i < _print_inlining_list->length(); i++) {
3867       tty->print("%s", _print_inlining_list->adr_at(i)->ss()->as_string());
3868     }
3869   }
3870 }
3871 
3872 // Dump inlining replay data to the stream.
3873 // Don't change thread state and acquire any locks.
3874 void Compile::dump_inline_data(outputStream* out) {
3875   InlineTree* inl_tree = ilt();
3876   if (inl_tree != NULL) {
3877     out->print(" inline %d", inl_tree->count());
3878     inl_tree->dump_replay_data(out);
3879   }
3880 }
3881 
3882 int Compile::cmp_expensive_nodes(Node* n1, Node* n2) {
3883   if (n1->Opcode() < n2->Opcode())      return -1;
3884   else if (n1->Opcode() > n2->Opcode()) return 1;
3885 
3886   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()));
3887   for (uint i = 1; i < n1->req(); i++) {
3888     if (n1->in(i) < n2->in(i))      return -1;
3889     else if (n1->in(i) > n2->in(i)) return 1;
3890   }
3891 
3892   return 0;
3893 }
3894 
3895 int Compile::cmp_expensive_nodes(Node** n1p, Node** n2p) {
3896   Node* n1 = *n1p;
3897   Node* n2 = *n2p;
3898 
3899   return cmp_expensive_nodes(n1, n2);
3900 }
3901 
3902 void Compile::sort_expensive_nodes() {
3903   if (!expensive_nodes_sorted()) {
3904     _expensive_nodes->sort(cmp_expensive_nodes);
3905   }
3906 }
3907 
3908 bool Compile::expensive_nodes_sorted() const {
3909   for (int i = 1; i < _expensive_nodes->length(); i++) {
3910     if (cmp_expensive_nodes(_expensive_nodes->adr_at(i), _expensive_nodes->adr_at(i-1)) < 0) {
3911       return false;
3912     }
3913   }
3914   return true;
3915 }
3916 
3917 bool Compile::should_optimize_expensive_nodes(PhaseIterGVN &igvn) {
3918   if (_expensive_nodes->length() == 0) {
3919     return false;
3920   }
3921 
3922   assert(OptimizeExpensiveOps, "optimization off?");
3923 
3924   // Take this opportunity to remove dead nodes from the list
3925   int j = 0;
3926   for (int i = 0; i < _expensive_nodes->length(); i++) {
3927     Node* n = _expensive_nodes->at(i);
3928     if (!n->is_unreachable(igvn)) {
3929       assert(n->is_expensive(), "should be expensive");
3930       _expensive_nodes->at_put(j, n);
3931       j++;
3932     }
3933   }
3934   _expensive_nodes->trunc_to(j);
3935 
3936   // Then sort the list so that similar nodes are next to each other
3937   // and check for at least two nodes of identical kind with same data
3938   // inputs.
3939   sort_expensive_nodes();
3940 
3941   for (int i = 0; i < _expensive_nodes->length()-1; i++) {
3942     if (cmp_expensive_nodes(_expensive_nodes->adr_at(i), _expensive_nodes->adr_at(i+1)) == 0) {
3943       return true;
3944     }
3945   }
3946 
3947   return false;
3948 }
3949 
3950 void Compile::cleanup_expensive_nodes(PhaseIterGVN &igvn) {
3951   if (_expensive_nodes->length() == 0) {
3952     return;
3953   }
3954 
3955   assert(OptimizeExpensiveOps, "optimization off?");
3956 
3957   // Sort to bring similar nodes next to each other and clear the
3958   // control input of nodes for which there's only a single copy.
3959   sort_expensive_nodes();
3960 
3961   int j = 0;
3962   int identical = 0;
3963   int i = 0;
3964   for (; i < _expensive_nodes->length()-1; i++) {
3965     assert(j <= i, "can't write beyond current index");
3966     if (_expensive_nodes->at(i)->Opcode() == _expensive_nodes->at(i+1)->Opcode()) {
3967       identical++;
3968       _expensive_nodes->at_put(j++, _expensive_nodes->at(i));
3969       continue;
3970     }
3971     if (identical > 0) {
3972       _expensive_nodes->at_put(j++, _expensive_nodes->at(i));
3973       identical = 0;
3974     } else {
3975       Node* n = _expensive_nodes->at(i);
3976       igvn.hash_delete(n);
3977       n->set_req(0, NULL);
3978       igvn.hash_insert(n);
3979     }
3980   }
3981   if (identical > 0) {
3982     _expensive_nodes->at_put(j++, _expensive_nodes->at(i));
3983   } else if (_expensive_nodes->length() >= 1) {
3984     Node* n = _expensive_nodes->at(i);
3985     igvn.hash_delete(n);
3986     n->set_req(0, NULL);
3987     igvn.hash_insert(n);
3988   }
3989   _expensive_nodes->trunc_to(j);
3990 }
3991 
3992 void Compile::add_expensive_node(Node * n) {
3993   assert(!_expensive_nodes->contains(n), "duplicate entry in expensive list");
3994   assert(n->is_expensive(), "expensive nodes with non-null control here only");
3995   assert(!n->is_CFG() && !n->is_Mem(), "no cfg or memory nodes here");
3996   if (OptimizeExpensiveOps) {
3997     _expensive_nodes->append(n);
3998   } else {
3999     // Clear control input and let IGVN optimize expensive nodes if
4000     // OptimizeExpensiveOps is off.
4001     n->set_req(0, NULL);
4002   }
4003 }
4004 
4005 /**
4006  * Remove the speculative part of types and clean up the graph
4007  */
4008 void Compile::remove_speculative_types(PhaseIterGVN &igvn) {
4009   if (UseTypeSpeculation) {
4010     Unique_Node_List worklist;
4011     worklist.push(root());
4012     int modified = 0;
4013     // Go over all type nodes that carry a speculative type, drop the
4014     // speculative part of the type and enqueue the node for an igvn
4015     // which may optimize it out.
4016     for (uint next = 0; next < worklist.size(); ++next) {
4017       Node *n  = worklist.at(next);
4018       if (n->is_Type()) {
4019         TypeNode* tn = n->as_Type();
4020         const Type* t = tn->type();
4021         const Type* t_no_spec = t->remove_speculative();
4022         if (t_no_spec != t) {
4023           bool in_hash = igvn.hash_delete(n);
4024           assert(in_hash, "node should be in igvn hash table");
4025           tn->set_type(t_no_spec);
4026           igvn.hash_insert(n);
4027           igvn._worklist.push(n); // give it a chance to go away
4028           modified++;
4029         }
4030       }
4031       uint max = n->len();
4032       for( uint i = 0; i < max; ++i ) {
4033         Node *m = n->in(i);
4034         if (not_a_node(m))  continue;
4035         worklist.push(m);
4036       }
4037     }
4038     // Drop the speculative part of all types in the igvn's type table
4039     igvn.remove_speculative_types();
4040     if (modified > 0) {
4041       igvn.optimize();
4042     }
4043 #ifdef ASSERT
4044     // Verify that after the IGVN is over no speculative type has resurfaced
4045     worklist.clear();
4046     worklist.push(root());
4047     for (uint next = 0; next < worklist.size(); ++next) {
4048       Node *n  = worklist.at(next);
4049       const Type* t = igvn.type_or_null(n);
4050       assert((t == NULL) || (t == t->remove_speculative()), "no more speculative types");
4051       if (n->is_Type()) {
4052         t = n->as_Type()->type();
4053         assert(t == t->remove_speculative(), "no more speculative types");
4054       }
4055       uint max = n->len();
4056       for( uint i = 0; i < max; ++i ) {
4057         Node *m = n->in(i);
4058         if (not_a_node(m))  continue;
4059         worklist.push(m);
4060       }
4061     }
4062     igvn.check_no_speculative_types();
4063 #endif
4064   }
4065 }
4066 
4067 // Convert integer value to a narrowed long type dependent on ctrl (for example, a range check)
4068 Node* Compile::constrained_convI2L(PhaseGVN* phase, Node* value, const TypeInt* itype, Node* ctrl) {
4069   if (ctrl != NULL) {
4070     // Express control dependency by a CastII node with a narrow type.
4071     value = new (phase->C) CastIINode(value, itype, false, true /* range check dependency */);
4072     // Make the CastII node dependent on the control input to prevent the narrowed ConvI2L
4073     // node from floating above the range check during loop optimizations. Otherwise, the
4074     // ConvI2L node may be eliminated independently of the range check, causing the data path
4075     // to become TOP while the control path is still there (although it's unreachable).
4076     value->set_req(0, ctrl);
4077     // Save CastII node to remove it after loop optimizations.
4078     phase->C->add_range_check_cast(value);
4079     value = phase->transform(value);
4080   }
4081   const TypeLong* ltype = TypeLong::make(itype->_lo, itype->_hi, itype->_widen);
4082   return phase->transform(new (phase->C) ConvI2LNode(value, ltype));
4083 }
4084 
4085 // Auxiliary method to support randomized stressing/fuzzing.
4086 //
4087 // This method can be called the arbitrary number of times, with current count
4088 // as the argument. The logic allows selecting a single candidate from the
4089 // running list of candidates as follows:
4090 //    int count = 0;
4091 //    Cand* selected = null;
4092 //    while(cand = cand->next()) {
4093 //      if (randomized_select(++count)) {
4094 //        selected = cand;
4095 //      }
4096 //    }
4097 //
4098 // Including count equalizes the chances any candidate is "selected".
4099 // This is useful when we don't have the complete list of candidates to choose
4100 // from uniformly. In this case, we need to adjust the randomicity of the
4101 // selection, or else we will end up biasing the selection towards the latter
4102 // candidates.
4103 //
4104 // Quick back-envelope calculation shows that for the list of n candidates
4105 // the equal probability for the candidate to persist as "best" can be
4106 // achieved by replacing it with "next" k-th candidate with the probability
4107 // of 1/k. It can be easily shown that by the end of the run, the
4108 // probability for any candidate is converged to 1/n, thus giving the
4109 // uniform distribution among all the candidates.
4110 //
4111 // We don't care about the domain size as long as (RANDOMIZED_DOMAIN / count) is large.
4112 #define RANDOMIZED_DOMAIN_POW 29
4113 #define RANDOMIZED_DOMAIN (1 << RANDOMIZED_DOMAIN_POW)
4114 #define RANDOMIZED_DOMAIN_MASK ((1 << (RANDOMIZED_DOMAIN_POW + 1)) - 1)
4115 bool Compile::randomized_select(int count) {
4116   assert(count > 0, "only positive");
4117   return (os::random() & RANDOMIZED_DOMAIN_MASK) < (RANDOMIZED_DOMAIN / count);
4118 }