1 /*
   2  * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "asm/assembler.hpp"
  27 #include "classfile/systemDictionary.hpp"
  28 #include "code/exceptionHandlerTable.hpp"
  29 #include "code/nmethod.hpp"
  30 #include "compiler/compileLog.hpp"
  31 #include "compiler/oopMap.hpp"
  32 #include "opto/addnode.hpp"
  33 #include "opto/block.hpp"
  34 #include "opto/c2compiler.hpp"
  35 #include "opto/callGenerator.hpp"
  36 #include "opto/callnode.hpp"
  37 #include "opto/cfgnode.hpp"
  38 #include "opto/chaitin.hpp"
  39 #include "opto/compile.hpp"
  40 #include "opto/connode.hpp"
  41 #include "opto/divnode.hpp"
  42 #include "opto/escape.hpp"
  43 #include "opto/idealGraphPrinter.hpp"
  44 #include "opto/loopnode.hpp"
  45 #include "opto/machnode.hpp"
  46 #include "opto/macro.hpp"
  47 #include "opto/matcher.hpp"
  48 #include "opto/memnode.hpp"
  49 #include "opto/mulnode.hpp"
  50 #include "opto/node.hpp"
  51 #include "opto/opcodes.hpp"
  52 #include "opto/output.hpp"
  53 #include "opto/parse.hpp"
  54 #include "opto/phaseX.hpp"
  55 #include "opto/rootnode.hpp"
  56 #include "opto/runtime.hpp"
  57 #include "opto/stringopts.hpp"
  58 #include "opto/type.hpp"
  59 #include "opto/vectornode.hpp"
  60 #include "runtime/arguments.hpp"
  61 #include "runtime/signature.hpp"
  62 #include "runtime/stubRoutines.hpp"
  63 #include "runtime/timer.hpp"
  64 #include "utilities/copy.hpp"
  65 #ifdef TARGET_ARCH_MODEL_x86_32
  66 # include "adfiles/ad_x86_32.hpp"
  67 #endif
  68 #ifdef TARGET_ARCH_MODEL_x86_64
  69 # include "adfiles/ad_x86_64.hpp"
  70 #endif
  71 #ifdef TARGET_ARCH_MODEL_sparc
  72 # include "adfiles/ad_sparc.hpp"
  73 #endif
  74 #ifdef TARGET_ARCH_MODEL_zero
  75 # include "adfiles/ad_zero.hpp"
  76 #endif
  77 #ifdef TARGET_ARCH_MODEL_arm
  78 # include "adfiles/ad_arm.hpp"
  79 #endif
  80 #ifdef TARGET_ARCH_MODEL_ppc
  81 # include "adfiles/ad_ppc.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 GrowableArray<CallGenerator*>(60);
 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 
 320 
 321 // Identify all nodes that are reachable from below, useful.
 322 // Use breadth-first pass that records state in a Unique_Node_List,
 323 // recursive traversal is slower.
 324 void Compile::identify_useful_nodes(Unique_Node_List &useful) {
 325   int estimated_worklist_size = unique();
 326   useful.map( estimated_worklist_size, NULL );  // preallocate space
 327 
 328   // Initialize worklist
 329   if (root() != NULL)     { useful.push(root()); }
 330   // If 'top' is cached, declare it useful to preserve cached node
 331   if( cached_top_node() ) { useful.push(cached_top_node()); }
 332 
 333   // Push all useful nodes onto the list, breadthfirst
 334   for( uint next = 0; next < useful.size(); ++next ) {
 335     assert( next < unique(), "Unique useful nodes < total nodes");
 336     Node *n  = useful.at(next);
 337     uint max = n->len();
 338     for( uint i = 0; i < max; ++i ) {
 339       Node *m = n->in(i);
 340       if( m == NULL ) continue;
 341       useful.push(m);
 342     }
 343   }
 344 }
 345 
 346 // Disconnect all useless nodes by disconnecting those at the boundary.
 347 void Compile::remove_useless_nodes(Unique_Node_List &useful) {
 348   uint next = 0;
 349   while( next < useful.size() ) {
 350     Node *n = useful.at(next++);
 351     // Use raw traversal of out edges since this code removes out edges
 352     int max = n->outcnt();
 353     for (int j = 0; j < max; ++j ) {
 354       Node* child = n->raw_out(j);
 355       if( ! useful.member(child) ) {
 356         assert( !child->is_top() || child != top(),
 357                 "If top is cached in Compile object it is in useful list");
 358         // Only need to remove this out-edge to the useless node
 359         n->raw_del_out(j);
 360         --j;
 361         --max;
 362       }
 363     }
 364     if (n->outcnt() == 1 && n->has_special_unique_user()) {
 365       record_for_igvn( n->unique_out() );
 366     }
 367   }
 368   debug_only(verify_graph_edges(true/*check for no_dead_code*/);)
 369 }
 370 
 371 //------------------------------frame_size_in_words-----------------------------
 372 // frame_slots in units of words
 373 int Compile::frame_size_in_words() const {
 374   // shift is 0 in LP32 and 1 in LP64
 375   const int shift = (LogBytesPerWord - LogBytesPerInt);
 376   int words = _frame_slots >> shift;
 377   assert( words << shift == _frame_slots, "frame size must be properly aligned in LP64" );
 378   return words;
 379 }
 380 
 381 // ============================================================================
 382 //------------------------------CompileWrapper---------------------------------
 383 class CompileWrapper : public StackObj {
 384   Compile *const _compile;
 385  public:
 386   CompileWrapper(Compile* compile);
 387 
 388   ~CompileWrapper();
 389 };
 390 
 391 CompileWrapper::CompileWrapper(Compile* compile) : _compile(compile) {
 392   // the Compile* pointer is stored in the current ciEnv:
 393   ciEnv* env = compile->env();
 394   assert(env == ciEnv::current(), "must already be a ciEnv active");
 395   assert(env->compiler_data() == NULL, "compile already active?");
 396   env->set_compiler_data(compile);
 397   assert(compile == Compile::current(), "sanity");
 398 
 399   compile->set_type_dict(NULL);
 400   compile->set_type_hwm(NULL);
 401   compile->set_type_last_size(0);
 402   compile->set_last_tf(NULL, NULL);
 403   compile->set_indexSet_arena(NULL);
 404   compile->set_indexSet_free_block_list(NULL);
 405   compile->init_type_arena();
 406   Type::Initialize(compile);
 407   _compile->set_scratch_buffer_blob(NULL);
 408   _compile->begin_method();
 409 }
 410 CompileWrapper::~CompileWrapper() {
 411   _compile->end_method();
 412   if (_compile->scratch_buffer_blob() != NULL)
 413     BufferBlob::free(_compile->scratch_buffer_blob());
 414   _compile->env()->set_compiler_data(NULL);
 415 }
 416 
 417 
 418 //----------------------------print_compile_messages---------------------------
 419 void Compile::print_compile_messages() {
 420 #ifndef PRODUCT
 421   // Check if recompiling
 422   if (_subsume_loads == false && PrintOpto) {
 423     // Recompiling without allowing machine instructions to subsume loads
 424     tty->print_cr("*********************************************************");
 425     tty->print_cr("** Bailout: Recompile without subsuming loads          **");
 426     tty->print_cr("*********************************************************");
 427   }
 428   if (_do_escape_analysis != DoEscapeAnalysis && PrintOpto) {
 429     // Recompiling without escape analysis
 430     tty->print_cr("*********************************************************");
 431     tty->print_cr("** Bailout: Recompile without escape analysis          **");
 432     tty->print_cr("*********************************************************");
 433   }
 434   if (env()->break_at_compile()) {
 435     // Open the debugger when compiling this method.
 436     tty->print("### Breaking when compiling: ");
 437     method()->print_short_name();
 438     tty->cr();
 439     BREAKPOINT;
 440   }
 441 
 442   if( PrintOpto ) {
 443     if (is_osr_compilation()) {
 444       tty->print("[OSR]%3d", _compile_id);
 445     } else {
 446       tty->print("%3d", _compile_id);
 447     }
 448   }
 449 #endif
 450 }
 451 
 452 
 453 //-----------------------init_scratch_buffer_blob------------------------------
 454 // Construct a temporary BufferBlob and cache it for this compile.
 455 void Compile::init_scratch_buffer_blob(int const_size) {
 456   // If there is already a scratch buffer blob allocated and the
 457   // constant section is big enough, use it.  Otherwise free the
 458   // current and allocate a new one.
 459   BufferBlob* blob = scratch_buffer_blob();
 460   if ((blob != NULL) && (const_size <= _scratch_const_size)) {
 461     // Use the current blob.
 462   } else {
 463     if (blob != NULL) {
 464       BufferBlob::free(blob);
 465     }
 466 
 467     ResourceMark rm;
 468     _scratch_const_size = const_size;
 469     int size = (MAX_inst_size + MAX_stubs_size + _scratch_const_size);
 470     blob = BufferBlob::create("Compile::scratch_buffer", size);
 471     // Record the buffer blob for next time.
 472     set_scratch_buffer_blob(blob);
 473     // Have we run out of code space?
 474     if (scratch_buffer_blob() == NULL) {
 475       // Let CompilerBroker disable further compilations.
 476       record_failure("Not enough space for scratch buffer in CodeCache");
 477       return;
 478     }
 479   }
 480 
 481   // Initialize the relocation buffers
 482   relocInfo* locs_buf = (relocInfo*) blob->content_end() - MAX_locs_size;
 483   set_scratch_locs_memory(locs_buf);
 484 }
 485 
 486 
 487 //-----------------------scratch_emit_size-------------------------------------
 488 // Helper function that computes size by emitting code
 489 uint Compile::scratch_emit_size(const Node* n) {
 490   // Start scratch_emit_size section.
 491   set_in_scratch_emit_size(true);
 492 
 493   // Emit into a trash buffer and count bytes emitted.
 494   // This is a pretty expensive way to compute a size,
 495   // but it works well enough if seldom used.
 496   // All common fixed-size instructions are given a size
 497   // method by the AD file.
 498   // Note that the scratch buffer blob and locs memory are
 499   // allocated at the beginning of the compile task, and
 500   // may be shared by several calls to scratch_emit_size.
 501   // The allocation of the scratch buffer blob is particularly
 502   // expensive, since it has to grab the code cache lock.
 503   BufferBlob* blob = this->scratch_buffer_blob();
 504   assert(blob != NULL, "Initialize BufferBlob at start");
 505   assert(blob->size() > MAX_inst_size, "sanity");
 506   relocInfo* locs_buf = scratch_locs_memory();
 507   address blob_begin = blob->content_begin();
 508   address blob_end   = (address)locs_buf;
 509   assert(blob->content_contains(blob_end), "sanity");
 510   CodeBuffer buf(blob_begin, blob_end - blob_begin);
 511   buf.initialize_consts_size(_scratch_const_size);
 512   buf.initialize_stubs_size(MAX_stubs_size);
 513   assert(locs_buf != NULL, "sanity");
 514   int lsize = MAX_locs_size / 3;
 515   buf.consts()->initialize_shared_locs(&locs_buf[lsize * 0], lsize);
 516   buf.insts()->initialize_shared_locs( &locs_buf[lsize * 1], lsize);
 517   buf.stubs()->initialize_shared_locs( &locs_buf[lsize * 2], lsize);
 518 
 519   // Do the emission.
 520 
 521   Label fakeL; // Fake label for branch instructions.
 522   bool is_branch = n->is_Branch() && n->as_Mach()->ideal_Opcode() != Op_Jump;
 523   if (is_branch) {
 524     MacroAssembler masm(&buf);
 525     masm.bind(fakeL);
 526     n->as_Mach()->label_set(&fakeL, 0);
 527   }
 528   n->emit(buf, this->regalloc());
 529   if (is_branch) // Clear the reference to fake label.
 530     n->as_Mach()->label_set(NULL, 0);
 531 
 532   // End scratch_emit_size section.
 533   set_in_scratch_emit_size(false);
 534 
 535   return buf.insts_size();
 536 }
 537 
 538 
 539 // ============================================================================
 540 //------------------------------Compile standard-------------------------------
 541 debug_only( int Compile::_debug_idx = 100000; )
 542 
 543 // Compile a method.  entry_bci is -1 for normal compilations and indicates
 544 // the continuation bci for on stack replacement.
 545 
 546 
 547 Compile::Compile( ciEnv* ci_env, C2Compiler* compiler, ciMethod* target, int osr_bci, bool subsume_loads, bool do_escape_analysis )
 548                 : Phase(Compiler),
 549                   _env(ci_env),
 550                   _log(ci_env->log()),
 551                   _compile_id(ci_env->compile_id()),
 552                   _save_argument_registers(false),
 553                   _stub_name(NULL),
 554                   _stub_function(NULL),
 555                   _stub_entry_point(NULL),
 556                   _method(target),
 557                   _entry_bci(osr_bci),
 558                   _initial_gvn(NULL),
 559                   _for_igvn(NULL),
 560                   _warm_calls(NULL),
 561                   _subsume_loads(subsume_loads),
 562                   _do_escape_analysis(do_escape_analysis),
 563                   _failure_reason(NULL),
 564                   _code_buffer("Compile::Fill_buffer"),
 565                   _orig_pc_slot(0),
 566                   _orig_pc_slot_offset_in_bytes(0),
 567                   _has_method_handle_invokes(false),
 568                   _mach_constant_base_node(NULL),
 569                   _node_bundling_limit(0),
 570                   _node_bundling_base(NULL),
 571                   _java_calls(0),
 572                   _inner_loops(0),
 573                   _scratch_const_size(-1),
 574                   _in_scratch_emit_size(false),
 575 #ifndef PRODUCT
 576                   _trace_opto_output(TraceOptoOutput || method()->has_option("TraceOptoOutput")),
 577                   _printer(IdealGraphPrinter::printer()),
 578 #endif
 579                   _congraph(NULL) {
 580   C = this;
 581 
 582   CompileWrapper cw(this);
 583 #ifndef PRODUCT
 584   if (TimeCompiler2) {
 585     tty->print(" ");
 586     target->holder()->name()->print();
 587     tty->print(".");
 588     target->print_short_name();
 589     tty->print("  ");
 590   }
 591   TraceTime t1("Total compilation time", &_t_totalCompilation, TimeCompiler, TimeCompiler2);
 592   TraceTime t2(NULL, &_t_methodCompilation, TimeCompiler, false);
 593   bool print_opto_assembly = PrintOptoAssembly || _method->has_option("PrintOptoAssembly");
 594   if (!print_opto_assembly) {
 595     bool print_assembly = (PrintAssembly || _method->should_print_assembly());
 596     if (print_assembly && !Disassembler::can_decode()) {
 597       tty->print_cr("PrintAssembly request changed to PrintOptoAssembly");
 598       print_opto_assembly = true;
 599     }
 600   }
 601   set_print_assembly(print_opto_assembly);
 602   set_parsed_irreducible_loop(false);
 603 #endif
 604 
 605   if (ProfileTraps) {
 606     // Make sure the method being compiled gets its own MDO,
 607     // so we can at least track the decompile_count().
 608     method()->ensure_method_data();
 609   }
 610 
 611   Init(::AliasLevel);
 612 
 613 
 614   print_compile_messages();
 615 
 616   if (UseOldInlining || PrintCompilation NOT_PRODUCT( || PrintOpto) )
 617     _ilt = InlineTree::build_inline_tree_root();
 618   else
 619     _ilt = NULL;
 620 
 621   // Even if NO memory addresses are used, MergeMem nodes must have at least 1 slice
 622   assert(num_alias_types() >= AliasIdxRaw, "");
 623 
 624 #define MINIMUM_NODE_HASH  1023
 625   // Node list that Iterative GVN will start with
 626   Unique_Node_List for_igvn(comp_arena());
 627   set_for_igvn(&for_igvn);
 628 
 629   // GVN that will be run immediately on new nodes
 630   uint estimated_size = method()->code_size()*4+64;
 631   estimated_size = (estimated_size < MINIMUM_NODE_HASH ? MINIMUM_NODE_HASH : estimated_size);
 632   PhaseGVN gvn(node_arena(), estimated_size);
 633   set_initial_gvn(&gvn);
 634 
 635   { // Scope for timing the parser
 636     TracePhase t3("parse", &_t_parser, true);
 637 
 638     // Put top into the hash table ASAP.
 639     initial_gvn()->transform_no_reclaim(top());
 640 
 641     // Set up tf(), start(), and find a CallGenerator.
 642     CallGenerator* cg = NULL;
 643     if (is_osr_compilation()) {
 644       const TypeTuple *domain = StartOSRNode::osr_domain();
 645       const TypeTuple *range = TypeTuple::make_range(method()->signature());
 646       init_tf(TypeFunc::make(domain, range));
 647       StartNode* s = new (this, 2) StartOSRNode(root(), domain);
 648       initial_gvn()->set_type_bottom(s);
 649       init_start(s);
 650       cg = CallGenerator::for_osr(method(), entry_bci());
 651     } else {
 652       // Normal case.
 653       init_tf(TypeFunc::make(method()));
 654       StartNode* s = new (this, 2) StartNode(root(), tf()->domain());
 655       initial_gvn()->set_type_bottom(s);
 656       init_start(s);
 657       if (method()->intrinsic_id() == vmIntrinsics::_Reference_get && UseG1GC) {
 658         // With java.lang.ref.reference.get() we must go through the
 659         // intrinsic when G1 is enabled - even when get() is the root
 660         // method of the compile - so that, if necessary, the value in
 661         // the referent field of the reference object gets recorded by
 662         // the pre-barrier code.
 663         // Specifically, if G1 is enabled, the value in the referent
 664         // field is recorded by the G1 SATB pre barrier. This will
 665         // result in the referent being marked live and the reference
 666         // object removed from the list of discovered references during
 667         // reference processing.
 668         cg = find_intrinsic(method(), false);
 669       }
 670       if (cg == NULL) {
 671         float past_uses = method()->interpreter_invocation_count();
 672         float expected_uses = past_uses;
 673         cg = CallGenerator::for_inline(method(), expected_uses);
 674       }
 675     }
 676     if (failing())  return;
 677     if (cg == NULL) {
 678       record_method_not_compilable_all_tiers("cannot parse method");
 679       return;
 680     }
 681     JVMState* jvms = build_start_state(start(), tf());
 682     if ((jvms = cg->generate(jvms)) == NULL) {
 683       record_method_not_compilable("method parse failed");
 684       return;
 685     }
 686     GraphKit kit(jvms);
 687 
 688     if (!kit.stopped()) {
 689       // Accept return values, and transfer control we know not where.
 690       // This is done by a special, unique ReturnNode bound to root.
 691       return_values(kit.jvms());
 692     }
 693 
 694     if (kit.has_exceptions()) {
 695       // Any exceptions that escape from this call must be rethrown
 696       // to whatever caller is dynamically above us on the stack.
 697       // This is done by a special, unique RethrowNode bound to root.
 698       rethrow_exceptions(kit.transfer_exceptions_into_jvms());
 699     }
 700 
 701     if (!failing() && has_stringbuilder()) {
 702       {
 703         // remove useless nodes to make the usage analysis simpler
 704         ResourceMark rm;
 705         PhaseRemoveUseless pru(initial_gvn(), &for_igvn);
 706       }
 707 
 708       {
 709         ResourceMark rm;
 710         print_method("Before StringOpts", 3);
 711         PhaseStringOpts pso(initial_gvn(), &for_igvn);
 712         print_method("After StringOpts", 3);
 713       }
 714 
 715       // now inline anything that we skipped the first time around
 716       while (_late_inlines.length() > 0) {
 717         CallGenerator* cg = _late_inlines.pop();
 718         cg->do_late_inline();
 719       }
 720     }
 721     assert(_late_inlines.length() == 0, "should have been processed");
 722 
 723     print_method("Before RemoveUseless", 3);
 724 
 725     // Remove clutter produced by parsing.
 726     if (!failing()) {
 727       ResourceMark rm;
 728       PhaseRemoveUseless pru(initial_gvn(), &for_igvn);
 729     }
 730   }
 731 
 732   // Note:  Large methods are capped off in do_one_bytecode().
 733   if (failing())  return;
 734 
 735   // After parsing, node notes are no longer automagic.
 736   // They must be propagated by register_new_node_with_optimizer(),
 737   // clone(), or the like.
 738   set_default_node_notes(NULL);
 739 
 740   for (;;) {
 741     int successes = Inline_Warm();
 742     if (failing())  return;
 743     if (successes == 0)  break;
 744   }
 745 
 746   // Drain the list.
 747   Finish_Warm();
 748 #ifndef PRODUCT
 749   if (_printer) {
 750     _printer->print_inlining(this);
 751   }
 752 #endif
 753 
 754   if (failing())  return;
 755   NOT_PRODUCT( verify_graph_edges(); )
 756 
 757   // Now optimize
 758   Optimize();
 759   if (failing())  return;
 760   NOT_PRODUCT( verify_graph_edges(); )
 761 
 762 #ifndef PRODUCT
 763   if (PrintIdeal) {
 764     ttyLocker ttyl;  // keep the following output all in one block
 765     // This output goes directly to the tty, not the compiler log.
 766     // To enable tools to match it up with the compilation activity,
 767     // be sure to tag this tty output with the compile ID.
 768     if (xtty != NULL) {
 769       xtty->head("ideal compile_id='%d'%s", compile_id(),
 770                  is_osr_compilation()    ? " compile_kind='osr'" :
 771                  "");
 772     }
 773     root()->dump(9999);
 774     if (xtty != NULL) {
 775       xtty->tail("ideal");
 776     }
 777   }
 778 #endif
 779 
 780   // Now that we know the size of all the monitors we can add a fixed slot
 781   // for the original deopt pc.
 782 
 783   _orig_pc_slot =  fixed_slots();
 784   int next_slot = _orig_pc_slot + (sizeof(address) / VMRegImpl::stack_slot_size);
 785   set_fixed_slots(next_slot);
 786 
 787   // Now generate code
 788   Code_Gen();
 789   if (failing())  return;
 790 
 791   // Check if we want to skip execution of all compiled code.
 792   {
 793 #ifndef PRODUCT
 794     if (OptoNoExecute) {
 795       record_method_not_compilable("+OptoNoExecute");  // Flag as failed
 796       return;
 797     }
 798     TracePhase t2("install_code", &_t_registerMethod, TimeCompiler);
 799 #endif
 800 
 801     if (is_osr_compilation()) {
 802       _code_offsets.set_value(CodeOffsets::Verified_Entry, 0);
 803       _code_offsets.set_value(CodeOffsets::OSR_Entry, _first_block_size);
 804     } else {
 805       _code_offsets.set_value(CodeOffsets::Verified_Entry, _first_block_size);
 806       _code_offsets.set_value(CodeOffsets::OSR_Entry, 0);
 807     }
 808 
 809     env()->register_method(_method, _entry_bci,
 810                            &_code_offsets,
 811                            _orig_pc_slot_offset_in_bytes,
 812                            code_buffer(),
 813                            frame_size_in_words(), _oop_map_set,
 814                            &_handler_table, &_inc_table,
 815                            compiler,
 816                            env()->comp_level(),
 817                            true, /*has_debug_info*/
 818                            has_unsafe_access()
 819                            );
 820   }
 821 }
 822 
 823 //------------------------------Compile----------------------------------------
 824 // Compile a runtime stub
 825 Compile::Compile( ciEnv* ci_env,
 826                   TypeFunc_generator generator,
 827                   address stub_function,
 828                   const char *stub_name,
 829                   int is_fancy_jump,
 830                   bool pass_tls,
 831                   bool save_arg_registers,
 832                   bool return_pc )
 833   : Phase(Compiler),
 834     _env(ci_env),
 835     _log(ci_env->log()),
 836     _compile_id(-1),
 837     _save_argument_registers(save_arg_registers),
 838     _method(NULL),
 839     _stub_name(stub_name),
 840     _stub_function(stub_function),
 841     _stub_entry_point(NULL),
 842     _entry_bci(InvocationEntryBci),
 843     _initial_gvn(NULL),
 844     _for_igvn(NULL),
 845     _warm_calls(NULL),
 846     _orig_pc_slot(0),
 847     _orig_pc_slot_offset_in_bytes(0),
 848     _subsume_loads(true),
 849     _do_escape_analysis(false),
 850     _failure_reason(NULL),
 851     _code_buffer("Compile::Fill_buffer"),
 852     _has_method_handle_invokes(false),
 853     _mach_constant_base_node(NULL),
 854     _node_bundling_limit(0),
 855     _node_bundling_base(NULL),
 856     _java_calls(0),
 857     _inner_loops(0),
 858 #ifndef PRODUCT
 859     _trace_opto_output(TraceOptoOutput),
 860     _printer(NULL),
 861 #endif
 862     _congraph(NULL) {
 863   C = this;
 864 
 865 #ifndef PRODUCT
 866   TraceTime t1(NULL, &_t_totalCompilation, TimeCompiler, false);
 867   TraceTime t2(NULL, &_t_stubCompilation, TimeCompiler, false);
 868   set_print_assembly(PrintFrameConverterAssembly);
 869   set_parsed_irreducible_loop(false);
 870 #endif
 871   CompileWrapper cw(this);
 872   Init(/*AliasLevel=*/ 0);
 873   init_tf((*generator)());
 874 
 875   {
 876     // The following is a dummy for the sake of GraphKit::gen_stub
 877     Unique_Node_List for_igvn(comp_arena());
 878     set_for_igvn(&for_igvn);  // not used, but some GraphKit guys push on this
 879     PhaseGVN gvn(Thread::current()->resource_area(),255);
 880     set_initial_gvn(&gvn);    // not significant, but GraphKit guys use it pervasively
 881     gvn.transform_no_reclaim(top());
 882 
 883     GraphKit kit;
 884     kit.gen_stub(stub_function, stub_name, is_fancy_jump, pass_tls, return_pc);
 885   }
 886 
 887   NOT_PRODUCT( verify_graph_edges(); )
 888   Code_Gen();
 889   if (failing())  return;
 890 
 891 
 892   // Entry point will be accessed using compile->stub_entry_point();
 893   if (code_buffer() == NULL) {
 894     Matcher::soft_match_failure();
 895   } else {
 896     if (PrintAssembly && (WizardMode || Verbose))
 897       tty->print_cr("### Stub::%s", stub_name);
 898 
 899     if (!failing()) {
 900       assert(_fixed_slots == 0, "no fixed slots used for runtime stubs");
 901 
 902       // Make the NMethod
 903       // For now we mark the frame as never safe for profile stackwalking
 904       RuntimeStub *rs = RuntimeStub::new_runtime_stub(stub_name,
 905                                                       code_buffer(),
 906                                                       CodeOffsets::frame_never_safe,
 907                                                       // _code_offsets.value(CodeOffsets::Frame_Complete),
 908                                                       frame_size_in_words(),
 909                                                       _oop_map_set,
 910                                                       save_arg_registers);
 911       assert(rs != NULL && rs->is_runtime_stub(), "sanity check");
 912 
 913       _stub_entry_point = rs->entry_point();
 914     }
 915   }
 916 }
 917 
 918 #ifndef PRODUCT
 919 void print_opto_verbose_signature( const TypeFunc *j_sig, const char *stub_name ) {
 920   if(PrintOpto && Verbose) {
 921     tty->print("%s   ", stub_name); j_sig->print_flattened(); tty->cr();
 922   }
 923 }
 924 #endif
 925 
 926 void Compile::print_codes() {
 927 }
 928 
 929 //------------------------------Init-------------------------------------------
 930 // Prepare for a single compilation
 931 void Compile::Init(int aliaslevel) {
 932   _unique  = 0;
 933   _regalloc = NULL;
 934 
 935   _tf      = NULL;  // filled in later
 936   _top     = NULL;  // cached later
 937   _matcher = NULL;  // filled in later
 938   _cfg     = NULL;  // filled in later
 939 
 940   set_24_bit_selection_and_mode(Use24BitFP, false);
 941 
 942   _node_note_array = NULL;
 943   _default_node_notes = NULL;
 944 
 945   _immutable_memory = NULL; // filled in at first inquiry
 946 
 947   // Globally visible Nodes
 948   // First set TOP to NULL to give safe behavior during creation of RootNode
 949   set_cached_top_node(NULL);
 950   set_root(new (this, 3) RootNode());
 951   // Now that you have a Root to point to, create the real TOP
 952   set_cached_top_node( new (this, 1) ConNode(Type::TOP) );
 953   set_recent_alloc(NULL, NULL);
 954 
 955   // Create Debug Information Recorder to record scopes, oopmaps, etc.
 956   env()->set_oop_recorder(new OopRecorder(comp_arena()));
 957   env()->set_debug_info(new DebugInformationRecorder(env()->oop_recorder()));
 958   env()->set_dependencies(new Dependencies(env()));
 959 
 960   _fixed_slots = 0;
 961   set_has_split_ifs(false);
 962   set_has_loops(has_method() && method()->has_loops()); // first approximation
 963   set_has_stringbuilder(false);
 964   _trap_can_recompile = false;  // no traps emitted yet
 965   _major_progress = true; // start out assuming good things will happen
 966   set_has_unsafe_access(false);
 967   Copy::zero_to_bytes(_trap_hist, sizeof(_trap_hist));
 968   set_decompile_count(0);
 969 
 970   set_do_freq_based_layout(BlockLayoutByFrequency || method_has_option("BlockLayoutByFrequency"));
 971   set_num_loop_opts(LoopOptsCount);
 972   set_do_inlining(Inline);
 973   set_max_inline_size(MaxInlineSize);
 974   set_freq_inline_size(FreqInlineSize);
 975   set_do_scheduling(OptoScheduling);
 976   set_do_count_invocations(false);
 977   set_do_method_data_update(false);
 978 
 979   if (debug_info()->recording_non_safepoints()) {
 980     set_node_note_array(new(comp_arena()) GrowableArray<Node_Notes*>
 981                         (comp_arena(), 8, 0, NULL));
 982     set_default_node_notes(Node_Notes::make(this));
 983   }
 984 
 985   // // -- Initialize types before each compile --
 986   // // Update cached type information
 987   // if( _method && _method->constants() )
 988   //   Type::update_loaded_types(_method, _method->constants());
 989 
 990   // Init alias_type map.
 991   if (!_do_escape_analysis && aliaslevel == 3)
 992     aliaslevel = 2;  // No unique types without escape analysis
 993   _AliasLevel = aliaslevel;
 994   const int grow_ats = 16;
 995   _max_alias_types = grow_ats;
 996   _alias_types   = NEW_ARENA_ARRAY(comp_arena(), AliasType*, grow_ats);
 997   AliasType* ats = NEW_ARENA_ARRAY(comp_arena(), AliasType,  grow_ats);
 998   Copy::zero_to_bytes(ats, sizeof(AliasType)*grow_ats);
 999   {
1000     for (int i = 0; i < grow_ats; i++)  _alias_types[i] = &ats[i];
1001   }
1002   // Initialize the first few types.
1003   _alias_types[AliasIdxTop]->Init(AliasIdxTop, NULL);
1004   _alias_types[AliasIdxBot]->Init(AliasIdxBot, TypePtr::BOTTOM);
1005   _alias_types[AliasIdxRaw]->Init(AliasIdxRaw, TypeRawPtr::BOTTOM);
1006   _num_alias_types = AliasIdxRaw+1;
1007   // Zero out the alias type cache.
1008   Copy::zero_to_bytes(_alias_cache, sizeof(_alias_cache));
1009   // A NULL adr_type hits in the cache right away.  Preload the right answer.
1010   probe_alias_cache(NULL)->_index = AliasIdxTop;
1011 
1012   _intrinsics = NULL;
1013   _macro_nodes = new(comp_arena()) GrowableArray<Node*>(comp_arena(), 8,  0, NULL);
1014   _predicate_opaqs = new(comp_arena()) GrowableArray<Node*>(comp_arena(), 8,  0, NULL);
1015   register_library_intrinsics();
1016 }
1017 
1018 //---------------------------init_start----------------------------------------
1019 // Install the StartNode on this compile object.
1020 void Compile::init_start(StartNode* s) {
1021   if (failing())
1022     return; // already failing
1023   assert(s == start(), "");
1024 }
1025 
1026 StartNode* Compile::start() const {
1027   assert(!failing(), "");
1028   for (DUIterator_Fast imax, i = root()->fast_outs(imax); i < imax; i++) {
1029     Node* start = root()->fast_out(i);
1030     if( start->is_Start() )
1031       return start->as_Start();
1032   }
1033   ShouldNotReachHere();
1034   return NULL;
1035 }
1036 
1037 //-------------------------------immutable_memory-------------------------------------
1038 // Access immutable memory
1039 Node* Compile::immutable_memory() {
1040   if (_immutable_memory != NULL) {
1041     return _immutable_memory;
1042   }
1043   StartNode* s = start();
1044   for (DUIterator_Fast imax, i = s->fast_outs(imax); true; i++) {
1045     Node *p = s->fast_out(i);
1046     if (p != s && p->as_Proj()->_con == TypeFunc::Memory) {
1047       _immutable_memory = p;
1048       return _immutable_memory;
1049     }
1050   }
1051   ShouldNotReachHere();
1052   return NULL;
1053 }
1054 
1055 //----------------------set_cached_top_node------------------------------------
1056 // Install the cached top node, and make sure Node::is_top works correctly.
1057 void Compile::set_cached_top_node(Node* tn) {
1058   if (tn != NULL)  verify_top(tn);
1059   Node* old_top = _top;
1060   _top = tn;
1061   // Calling Node::setup_is_top allows the nodes the chance to adjust
1062   // their _out arrays.
1063   if (_top != NULL)     _top->setup_is_top();
1064   if (old_top != NULL)  old_top->setup_is_top();
1065   assert(_top == NULL || top()->is_top(), "");
1066 }
1067 
1068 #ifndef PRODUCT
1069 void Compile::verify_top(Node* tn) const {
1070   if (tn != NULL) {
1071     assert(tn->is_Con(), "top node must be a constant");
1072     assert(((ConNode*)tn)->type() == Type::TOP, "top node must have correct type");
1073     assert(tn->in(0) != NULL, "must have live top node");
1074   }
1075 }
1076 #endif
1077 
1078 
1079 ///-------------------Managing Per-Node Debug & Profile Info-------------------
1080 
1081 void Compile::grow_node_notes(GrowableArray<Node_Notes*>* arr, int grow_by) {
1082   guarantee(arr != NULL, "");
1083   int num_blocks = arr->length();
1084   if (grow_by < num_blocks)  grow_by = num_blocks;
1085   int num_notes = grow_by * _node_notes_block_size;
1086   Node_Notes* notes = NEW_ARENA_ARRAY(node_arena(), Node_Notes, num_notes);
1087   Copy::zero_to_bytes(notes, num_notes * sizeof(Node_Notes));
1088   while (num_notes > 0) {
1089     arr->append(notes);
1090     notes     += _node_notes_block_size;
1091     num_notes -= _node_notes_block_size;
1092   }
1093   assert(num_notes == 0, "exact multiple, please");
1094 }
1095 
1096 bool Compile::copy_node_notes_to(Node* dest, Node* source) {
1097   if (source == NULL || dest == NULL)  return false;
1098 
1099   if (dest->is_Con())
1100     return false;               // Do not push debug info onto constants.
1101 
1102 #ifdef ASSERT
1103   // Leave a bread crumb trail pointing to the original node:
1104   if (dest != NULL && dest != source && dest->debug_orig() == NULL) {
1105     dest->set_debug_orig(source);
1106   }
1107 #endif
1108 
1109   if (node_note_array() == NULL)
1110     return false;               // Not collecting any notes now.
1111 
1112   // This is a copy onto a pre-existing node, which may already have notes.
1113   // If both nodes have notes, do not overwrite any pre-existing notes.
1114   Node_Notes* source_notes = node_notes_at(source->_idx);
1115   if (source_notes == NULL || source_notes->is_clear())  return false;
1116   Node_Notes* dest_notes   = node_notes_at(dest->_idx);
1117   if (dest_notes == NULL || dest_notes->is_clear()) {
1118     return set_node_notes_at(dest->_idx, source_notes);
1119   }
1120 
1121   Node_Notes merged_notes = (*source_notes);
1122   // The order of operations here ensures that dest notes will win...
1123   merged_notes.update_from(dest_notes);
1124   return set_node_notes_at(dest->_idx, &merged_notes);
1125 }
1126 
1127 
1128 //--------------------------allow_range_check_smearing-------------------------
1129 // Gating condition for coalescing similar range checks.
1130 // Sometimes we try 'speculatively' replacing a series of a range checks by a
1131 // single covering check that is at least as strong as any of them.
1132 // If the optimization succeeds, the simplified (strengthened) range check
1133 // will always succeed.  If it fails, we will deopt, and then give up
1134 // on the optimization.
1135 bool Compile::allow_range_check_smearing() const {
1136   // If this method has already thrown a range-check,
1137   // assume it was because we already tried range smearing
1138   // and it failed.
1139   uint already_trapped = trap_count(Deoptimization::Reason_range_check);
1140   return !already_trapped;
1141 }
1142 
1143 
1144 //------------------------------flatten_alias_type-----------------------------
1145 const TypePtr *Compile::flatten_alias_type( const TypePtr *tj ) const {
1146   int offset = tj->offset();
1147   TypePtr::PTR ptr = tj->ptr();
1148 
1149   // Known instance (scalarizable allocation) alias only with itself.
1150   bool is_known_inst = tj->isa_oopptr() != NULL &&
1151                        tj->is_oopptr()->is_known_instance();
1152 
1153   // Process weird unsafe references.
1154   if (offset == Type::OffsetBot && (tj->isa_instptr() /*|| tj->isa_klassptr()*/)) {
1155     assert(InlineUnsafeOps, "indeterminate pointers come only from unsafe ops");
1156     assert(!is_known_inst, "scalarizable allocation should not have unsafe references");
1157     tj = TypeOopPtr::BOTTOM;
1158     ptr = tj->ptr();
1159     offset = tj->offset();
1160   }
1161 
1162   // Array pointers need some flattening
1163   const TypeAryPtr *ta = tj->isa_aryptr();
1164   if( ta && is_known_inst ) {
1165     if ( offset != Type::OffsetBot &&
1166          offset > arrayOopDesc::length_offset_in_bytes() ) {
1167       offset = Type::OffsetBot; // Flatten constant access into array body only
1168       tj = ta = TypeAryPtr::make(ptr, ta->ary(), ta->klass(), true, offset, ta->instance_id());
1169     }
1170   } else if( ta && _AliasLevel >= 2 ) {
1171     // For arrays indexed by constant indices, we flatten the alias
1172     // space to include all of the array body.  Only the header, klass
1173     // and array length can be accessed un-aliased.
1174     if( offset != Type::OffsetBot ) {
1175       if( ta->const_oop() ) { // methodDataOop or methodOop
1176         offset = Type::OffsetBot;   // Flatten constant access into array body
1177         tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),ta->ary(),ta->klass(),false,offset);
1178       } else if( offset == arrayOopDesc::length_offset_in_bytes() ) {
1179         // range is OK as-is.
1180         tj = ta = TypeAryPtr::RANGE;
1181       } else if( offset == oopDesc::klass_offset_in_bytes() ) {
1182         tj = TypeInstPtr::KLASS; // all klass loads look alike
1183         ta = TypeAryPtr::RANGE; // generic ignored junk
1184         ptr = TypePtr::BotPTR;
1185       } else if( offset == oopDesc::mark_offset_in_bytes() ) {
1186         tj = TypeInstPtr::MARK;
1187         ta = TypeAryPtr::RANGE; // generic ignored junk
1188         ptr = TypePtr::BotPTR;
1189       } else {                  // Random constant offset into array body
1190         offset = Type::OffsetBot;   // Flatten constant access into array body
1191         tj = ta = TypeAryPtr::make(ptr,ta->ary(),ta->klass(),false,offset);
1192       }
1193     }
1194     // Arrays of fixed size alias with arrays of unknown size.
1195     if (ta->size() != TypeInt::POS) {
1196       const TypeAry *tary = TypeAry::make(ta->elem(), TypeInt::POS);
1197       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,ta->klass(),false,offset);
1198     }
1199     // Arrays of known objects become arrays of unknown objects.
1200     if (ta->elem()->isa_narrowoop() && ta->elem() != TypeNarrowOop::BOTTOM) {
1201       const TypeAry *tary = TypeAry::make(TypeNarrowOop::BOTTOM, ta->size());
1202       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,NULL,false,offset);
1203     }
1204     if (ta->elem()->isa_oopptr() && ta->elem() != TypeInstPtr::BOTTOM) {
1205       const TypeAry *tary = TypeAry::make(TypeInstPtr::BOTTOM, ta->size());
1206       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,NULL,false,offset);
1207     }
1208     // Arrays of bytes and of booleans both use 'bastore' and 'baload' so
1209     // cannot be distinguished by bytecode alone.
1210     if (ta->elem() == TypeInt::BOOL) {
1211       const TypeAry *tary = TypeAry::make(TypeInt::BYTE, ta->size());
1212       ciKlass* aklass = ciTypeArrayKlass::make(T_BYTE);
1213       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,aklass,false,offset);
1214     }
1215     // During the 2nd round of IterGVN, NotNull castings are removed.
1216     // Make sure the Bottom and NotNull variants alias the same.
1217     // Also, make sure exact and non-exact variants alias the same.
1218     if( ptr == TypePtr::NotNull || ta->klass_is_exact() ) {
1219       tj = ta = TypeAryPtr::make(TypePtr::BotPTR,ta->ary(),ta->klass(),false,offset);
1220     }
1221   }
1222 
1223   // Oop pointers need some flattening
1224   const TypeInstPtr *to = tj->isa_instptr();
1225   if( to && _AliasLevel >= 2 && to != TypeOopPtr::BOTTOM ) {
1226     ciInstanceKlass *k = to->klass()->as_instance_klass();
1227     if( ptr == TypePtr::Constant ) {
1228       if (to->klass() != ciEnv::current()->Class_klass() ||
1229           offset < k->size_helper() * wordSize) {
1230         // No constant oop pointers (such as Strings); they alias with
1231         // unknown strings.
1232         assert(!is_known_inst, "not scalarizable allocation");
1233         tj = to = TypeInstPtr::make(TypePtr::BotPTR,to->klass(),false,0,offset);
1234       }
1235     } else if( is_known_inst ) {
1236       tj = to; // Keep NotNull and klass_is_exact for instance type
1237     } else if( ptr == TypePtr::NotNull || to->klass_is_exact() ) {
1238       // During the 2nd round of IterGVN, NotNull castings are removed.
1239       // Make sure the Bottom and NotNull variants alias the same.
1240       // Also, make sure exact and non-exact variants alias the same.
1241       tj = to = TypeInstPtr::make(TypePtr::BotPTR,to->klass(),false,0,offset);
1242     }
1243     // Canonicalize the holder of this field
1244     if (offset >= 0 && offset < instanceOopDesc::base_offset_in_bytes()) {
1245       // First handle header references such as a LoadKlassNode, even if the
1246       // object's klass is unloaded at compile time (4965979).
1247       if (!is_known_inst) { // Do it only for non-instance types
1248         tj = to = TypeInstPtr::make(TypePtr::BotPTR, env()->Object_klass(), false, NULL, offset);
1249       }
1250     } else if (offset < 0 || offset >= k->size_helper() * wordSize) {
1251       // Static fields are in the space above the normal instance
1252       // fields in the java.lang.Class instance.
1253       if (to->klass() != ciEnv::current()->Class_klass()) {
1254         to = NULL;
1255         tj = TypeOopPtr::BOTTOM;
1256         offset = tj->offset();
1257       }
1258     } else {
1259       ciInstanceKlass *canonical_holder = k->get_canonical_holder(offset);
1260       if (!k->equals(canonical_holder) || tj->offset() != offset) {
1261         if( is_known_inst ) {
1262           tj = to = TypeInstPtr::make(to->ptr(), canonical_holder, true, NULL, offset, to->instance_id());
1263         } else {
1264           tj = to = TypeInstPtr::make(to->ptr(), canonical_holder, false, NULL, offset);
1265         }
1266       }
1267     }
1268   }
1269 
1270   // Klass pointers to object array klasses need some flattening
1271   const TypeKlassPtr *tk = tj->isa_klassptr();
1272   if( tk ) {
1273     // If we are referencing a field within a Klass, we need
1274     // to assume the worst case of an Object.  Both exact and
1275     // inexact types must flatten to the same alias class.
1276     // Since the flattened result for a klass is defined to be
1277     // precisely java.lang.Object, use a constant ptr.
1278     if ( offset == Type::OffsetBot || (offset >= 0 && (size_t)offset < sizeof(Klass)) ) {
1279 
1280       tj = tk = TypeKlassPtr::make(TypePtr::Constant,
1281                                    TypeKlassPtr::OBJECT->klass(),
1282                                    offset);
1283     }
1284 
1285     ciKlass* klass = tk->klass();
1286     if( klass->is_obj_array_klass() ) {
1287       ciKlass* k = TypeAryPtr::OOPS->klass();
1288       if( !k || !k->is_loaded() )                  // Only fails for some -Xcomp runs
1289         k = TypeInstPtr::BOTTOM->klass();
1290       tj = tk = TypeKlassPtr::make( TypePtr::NotNull, k, offset );
1291     }
1292 
1293     // Check for precise loads from the primary supertype array and force them
1294     // to the supertype cache alias index.  Check for generic array loads from
1295     // the primary supertype array and also force them to the supertype cache
1296     // alias index.  Since the same load can reach both, we need to merge
1297     // these 2 disparate memories into the same alias class.  Since the
1298     // primary supertype array is read-only, there's no chance of confusion
1299     // where we bypass an array load and an array store.
1300     uint off2 = offset - Klass::primary_supers_offset_in_bytes();
1301     if( offset == Type::OffsetBot ||
1302         off2 < Klass::primary_super_limit()*wordSize ) {
1303       offset = sizeof(oopDesc) +Klass::secondary_super_cache_offset_in_bytes();
1304       tj = tk = TypeKlassPtr::make( TypePtr::NotNull, tk->klass(), offset );
1305     }
1306   }
1307 
1308   // Flatten all Raw pointers together.
1309   if (tj->base() == Type::RawPtr)
1310     tj = TypeRawPtr::BOTTOM;
1311 
1312   if (tj->base() == Type::AnyPtr)
1313     tj = TypePtr::BOTTOM;      // An error, which the caller must check for.
1314 
1315   // Flatten all to bottom for now
1316   switch( _AliasLevel ) {
1317   case 0:
1318     tj = TypePtr::BOTTOM;
1319     break;
1320   case 1:                       // Flatten to: oop, static, field or array
1321     switch (tj->base()) {
1322     //case Type::AryPtr: tj = TypeAryPtr::RANGE;    break;
1323     case Type::RawPtr:   tj = TypeRawPtr::BOTTOM;   break;
1324     case Type::AryPtr:   // do not distinguish arrays at all
1325     case Type::InstPtr:  tj = TypeInstPtr::BOTTOM;  break;
1326     case Type::KlassPtr: tj = TypeKlassPtr::OBJECT; break;
1327     case Type::AnyPtr:   tj = TypePtr::BOTTOM;      break;  // caller checks it
1328     default: ShouldNotReachHere();
1329     }
1330     break;
1331   case 2:                       // No collapsing at level 2; keep all splits
1332   case 3:                       // No collapsing at level 3; keep all splits
1333     break;
1334   default:
1335     Unimplemented();
1336   }
1337 
1338   offset = tj->offset();
1339   assert( offset != Type::OffsetTop, "Offset has fallen from constant" );
1340 
1341   assert( (offset != Type::OffsetBot && tj->base() != Type::AryPtr) ||
1342           (offset == Type::OffsetBot && tj->base() == Type::AryPtr) ||
1343           (offset == Type::OffsetBot && tj == TypeOopPtr::BOTTOM) ||
1344           (offset == Type::OffsetBot && tj == TypePtr::BOTTOM) ||
1345           (offset == oopDesc::mark_offset_in_bytes() && tj->base() == Type::AryPtr) ||
1346           (offset == oopDesc::klass_offset_in_bytes() && tj->base() == Type::AryPtr) ||
1347           (offset == arrayOopDesc::length_offset_in_bytes() && tj->base() == Type::AryPtr)  ,
1348           "For oops, klasses, raw offset must be constant; for arrays the offset is never known" );
1349   assert( tj->ptr() != TypePtr::TopPTR &&
1350           tj->ptr() != TypePtr::AnyNull &&
1351           tj->ptr() != TypePtr::Null, "No imprecise addresses" );
1352 //    assert( tj->ptr() != TypePtr::Constant ||
1353 //            tj->base() == Type::RawPtr ||
1354 //            tj->base() == Type::KlassPtr, "No constant oop addresses" );
1355 
1356   return tj;
1357 }
1358 
1359 void Compile::AliasType::Init(int i, const TypePtr* at) {
1360   _index = i;
1361   _adr_type = at;
1362   _field = NULL;
1363   _is_rewritable = true; // default
1364   const TypeOopPtr *atoop = (at != NULL) ? at->isa_oopptr() : NULL;
1365   if (atoop != NULL && atoop->is_known_instance()) {
1366     const TypeOopPtr *gt = atoop->cast_to_instance_id(TypeOopPtr::InstanceBot);
1367     _general_index = Compile::current()->get_alias_index(gt);
1368   } else {
1369     _general_index = 0;
1370   }
1371 }
1372 
1373 //---------------------------------print_on------------------------------------
1374 #ifndef PRODUCT
1375 void Compile::AliasType::print_on(outputStream* st) {
1376   if (index() < 10)
1377         st->print("@ <%d> ", index());
1378   else  st->print("@ <%d>",  index());
1379   st->print(is_rewritable() ? "   " : " RO");
1380   int offset = adr_type()->offset();
1381   if (offset == Type::OffsetBot)
1382         st->print(" +any");
1383   else  st->print(" +%-3d", offset);
1384   st->print(" in ");
1385   adr_type()->dump_on(st);
1386   const TypeOopPtr* tjp = adr_type()->isa_oopptr();
1387   if (field() != NULL && tjp) {
1388     if (tjp->klass()  != field()->holder() ||
1389         tjp->offset() != field()->offset_in_bytes()) {
1390       st->print(" != ");
1391       field()->print();
1392       st->print(" ***");
1393     }
1394   }
1395 }
1396 
1397 void print_alias_types() {
1398   Compile* C = Compile::current();
1399   tty->print_cr("--- Alias types, AliasIdxBot .. %d", C->num_alias_types()-1);
1400   for (int idx = Compile::AliasIdxBot; idx < C->num_alias_types(); idx++) {
1401     C->alias_type(idx)->print_on(tty);
1402     tty->cr();
1403   }
1404 }
1405 #endif
1406 
1407 
1408 //----------------------------probe_alias_cache--------------------------------
1409 Compile::AliasCacheEntry* Compile::probe_alias_cache(const TypePtr* adr_type) {
1410   intptr_t key = (intptr_t) adr_type;
1411   key ^= key >> logAliasCacheSize;
1412   return &_alias_cache[key & right_n_bits(logAliasCacheSize)];
1413 }
1414 
1415 
1416 //-----------------------------grow_alias_types--------------------------------
1417 void Compile::grow_alias_types() {
1418   const int old_ats  = _max_alias_types; // how many before?
1419   const int new_ats  = old_ats;          // how many more?
1420   const int grow_ats = old_ats+new_ats;  // how many now?
1421   _max_alias_types = grow_ats;
1422   _alias_types =  REALLOC_ARENA_ARRAY(comp_arena(), AliasType*, _alias_types, old_ats, grow_ats);
1423   AliasType* ats =    NEW_ARENA_ARRAY(comp_arena(), AliasType, new_ats);
1424   Copy::zero_to_bytes(ats, sizeof(AliasType)*new_ats);
1425   for (int i = 0; i < new_ats; i++)  _alias_types[old_ats+i] = &ats[i];
1426 }
1427 
1428 
1429 //--------------------------------find_alias_type------------------------------
1430 Compile::AliasType* Compile::find_alias_type(const TypePtr* adr_type, bool no_create, ciField* original_field) {
1431   if (_AliasLevel == 0)
1432     return alias_type(AliasIdxBot);
1433 
1434   AliasCacheEntry* ace = probe_alias_cache(adr_type);
1435   if (ace->_adr_type == adr_type) {
1436     return alias_type(ace->_index);
1437   }
1438 
1439   // Handle special cases.
1440   if (adr_type == NULL)             return alias_type(AliasIdxTop);
1441   if (adr_type == TypePtr::BOTTOM)  return alias_type(AliasIdxBot);
1442 
1443   // Do it the slow way.
1444   const TypePtr* flat = flatten_alias_type(adr_type);
1445 
1446 #ifdef ASSERT
1447   assert(flat == flatten_alias_type(flat), "idempotent");
1448   assert(flat != TypePtr::BOTTOM,     "cannot alias-analyze an untyped ptr");
1449   if (flat->isa_oopptr() && !flat->isa_klassptr()) {
1450     const TypeOopPtr* foop = flat->is_oopptr();
1451     // Scalarizable allocations have exact klass always.
1452     bool exact = !foop->klass_is_exact() || foop->is_known_instance();
1453     const TypePtr* xoop = foop->cast_to_exactness(exact)->is_ptr();
1454     assert(foop == flatten_alias_type(xoop), "exactness must not affect alias type");
1455   }
1456   assert(flat == flatten_alias_type(flat), "exact bit doesn't matter");
1457 #endif
1458 
1459   int idx = AliasIdxTop;
1460   for (int i = 0; i < num_alias_types(); i++) {
1461     if (alias_type(i)->adr_type() == flat) {
1462       idx = i;
1463       break;
1464     }
1465   }
1466 
1467   if (idx == AliasIdxTop) {
1468     if (no_create)  return NULL;
1469     // Grow the array if necessary.
1470     if (_num_alias_types == _max_alias_types)  grow_alias_types();
1471     // Add a new alias type.
1472     idx = _num_alias_types++;
1473     _alias_types[idx]->Init(idx, flat);
1474     if (flat == TypeInstPtr::KLASS)  alias_type(idx)->set_rewritable(false);
1475     if (flat == TypeAryPtr::RANGE)   alias_type(idx)->set_rewritable(false);
1476     if (flat->isa_instptr()) {
1477       if (flat->offset() == java_lang_Class::klass_offset_in_bytes()
1478           && flat->is_instptr()->klass() == env()->Class_klass())
1479         alias_type(idx)->set_rewritable(false);
1480     }
1481     if (flat->isa_klassptr()) {
1482       if (flat->offset() == Klass::super_check_offset_offset_in_bytes() + (int)sizeof(oopDesc))
1483         alias_type(idx)->set_rewritable(false);
1484       if (flat->offset() == Klass::modifier_flags_offset_in_bytes() + (int)sizeof(oopDesc))
1485         alias_type(idx)->set_rewritable(false);
1486       if (flat->offset() == Klass::access_flags_offset_in_bytes() + (int)sizeof(oopDesc))
1487         alias_type(idx)->set_rewritable(false);
1488       if (flat->offset() == Klass::java_mirror_offset_in_bytes() + (int)sizeof(oopDesc))
1489         alias_type(idx)->set_rewritable(false);
1490     }
1491     // %%% (We would like to finalize JavaThread::threadObj_offset(),
1492     // but the base pointer type is not distinctive enough to identify
1493     // references into JavaThread.)
1494 
1495     // Check for final fields.
1496     const TypeInstPtr* tinst = flat->isa_instptr();
1497     if (tinst && tinst->offset() >= instanceOopDesc::base_offset_in_bytes()) {
1498       ciField* field;
1499       if (tinst->const_oop() != NULL &&
1500           tinst->klass() == ciEnv::current()->Class_klass() &&
1501           tinst->offset() >= (tinst->klass()->as_instance_klass()->size_helper() * wordSize)) {
1502         // static field
1503         ciInstanceKlass* k = tinst->const_oop()->as_instance()->java_lang_Class_klass()->as_instance_klass();
1504         field = k->get_field_by_offset(tinst->offset(), true);
1505       } else {
1506         ciInstanceKlass *k = tinst->klass()->as_instance_klass();
1507         field = k->get_field_by_offset(tinst->offset(), false);
1508       }
1509       assert(field == NULL ||
1510              original_field == NULL ||
1511              (field->holder() == original_field->holder() &&
1512               field->offset() == original_field->offset() &&
1513               field->is_static() == original_field->is_static()), "wrong field?");
1514       // Set field() and is_rewritable() attributes.
1515       if (field != NULL)  alias_type(idx)->set_field(field);
1516     }
1517   }
1518 
1519   // Fill the cache for next time.
1520   ace->_adr_type = adr_type;
1521   ace->_index    = idx;
1522   assert(alias_type(adr_type) == alias_type(idx),  "type must be installed");
1523 
1524   // Might as well try to fill the cache for the flattened version, too.
1525   AliasCacheEntry* face = probe_alias_cache(flat);
1526   if (face->_adr_type == NULL) {
1527     face->_adr_type = flat;
1528     face->_index    = idx;
1529     assert(alias_type(flat) == alias_type(idx), "flat type must work too");
1530   }
1531 
1532   return alias_type(idx);
1533 }
1534 
1535 
1536 Compile::AliasType* Compile::alias_type(ciField* field) {
1537   const TypeOopPtr* t;
1538   if (field->is_static())
1539     t = TypeInstPtr::make(field->holder()->java_mirror());
1540   else
1541     t = TypeOopPtr::make_from_klass_raw(field->holder());
1542   AliasType* atp = alias_type(t->add_offset(field->offset_in_bytes()), field);
1543   assert(field->is_final() == !atp->is_rewritable(), "must get the rewritable bits correct");
1544   return atp;
1545 }
1546 
1547 
1548 //------------------------------have_alias_type--------------------------------
1549 bool Compile::have_alias_type(const TypePtr* adr_type) {
1550   AliasCacheEntry* ace = probe_alias_cache(adr_type);
1551   if (ace->_adr_type == adr_type) {
1552     return true;
1553   }
1554 
1555   // Handle special cases.
1556   if (adr_type == NULL)             return true;
1557   if (adr_type == TypePtr::BOTTOM)  return true;
1558 
1559   return find_alias_type(adr_type, true, NULL) != NULL;
1560 }
1561 
1562 //-----------------------------must_alias--------------------------------------
1563 // True if all values of the given address type are in the given alias category.
1564 bool Compile::must_alias(const TypePtr* adr_type, int alias_idx) {
1565   if (alias_idx == AliasIdxBot)         return true;  // the universal category
1566   if (adr_type == NULL)                 return true;  // NULL serves as TypePtr::TOP
1567   if (alias_idx == AliasIdxTop)         return false; // the empty category
1568   if (adr_type->base() == Type::AnyPtr) return false; // TypePtr::BOTTOM or its twins
1569 
1570   // the only remaining possible overlap is identity
1571   int adr_idx = get_alias_index(adr_type);
1572   assert(adr_idx != AliasIdxBot && adr_idx != AliasIdxTop, "");
1573   assert(adr_idx == alias_idx ||
1574          (alias_type(alias_idx)->adr_type() != TypeOopPtr::BOTTOM
1575           && adr_type                       != TypeOopPtr::BOTTOM),
1576          "should not be testing for overlap with an unsafe pointer");
1577   return adr_idx == alias_idx;
1578 }
1579 
1580 //------------------------------can_alias--------------------------------------
1581 // True if any values of the given address type are in the given alias category.
1582 bool Compile::can_alias(const TypePtr* adr_type, int alias_idx) {
1583   if (alias_idx == AliasIdxTop)         return false; // the empty category
1584   if (adr_type == NULL)                 return false; // NULL serves as TypePtr::TOP
1585   if (alias_idx == AliasIdxBot)         return true;  // the universal category
1586   if (adr_type->base() == Type::AnyPtr) return true;  // TypePtr::BOTTOM or its twins
1587 
1588   // the only remaining possible overlap is identity
1589   int adr_idx = get_alias_index(adr_type);
1590   assert(adr_idx != AliasIdxBot && adr_idx != AliasIdxTop, "");
1591   return adr_idx == alias_idx;
1592 }
1593 
1594 
1595 
1596 //---------------------------pop_warm_call-------------------------------------
1597 WarmCallInfo* Compile::pop_warm_call() {
1598   WarmCallInfo* wci = _warm_calls;
1599   if (wci != NULL)  _warm_calls = wci->remove_from(wci);
1600   return wci;
1601 }
1602 
1603 //----------------------------Inline_Warm--------------------------------------
1604 int Compile::Inline_Warm() {
1605   // If there is room, try to inline some more warm call sites.
1606   // %%% Do a graph index compaction pass when we think we're out of space?
1607   if (!InlineWarmCalls)  return 0;
1608 
1609   int calls_made_hot = 0;
1610   int room_to_grow   = NodeCountInliningCutoff - unique();
1611   int amount_to_grow = MIN2(room_to_grow, (int)NodeCountInliningStep);
1612   int amount_grown   = 0;
1613   WarmCallInfo* call;
1614   while (amount_to_grow > 0 && (call = pop_warm_call()) != NULL) {
1615     int est_size = (int)call->size();
1616     if (est_size > (room_to_grow - amount_grown)) {
1617       // This one won't fit anyway.  Get rid of it.
1618       call->make_cold();
1619       continue;
1620     }
1621     call->make_hot();
1622     calls_made_hot++;
1623     amount_grown   += est_size;
1624     amount_to_grow -= est_size;
1625   }
1626 
1627   if (calls_made_hot > 0)  set_major_progress();
1628   return calls_made_hot;
1629 }
1630 
1631 
1632 //----------------------------Finish_Warm--------------------------------------
1633 void Compile::Finish_Warm() {
1634   if (!InlineWarmCalls)  return;
1635   if (failing())  return;
1636   if (warm_calls() == NULL)  return;
1637 
1638   // Clean up loose ends, if we are out of space for inlining.
1639   WarmCallInfo* call;
1640   while ((call = pop_warm_call()) != NULL) {
1641     call->make_cold();
1642   }
1643 }
1644 
1645 //---------------------cleanup_loop_predicates-----------------------
1646 // Remove the opaque nodes that protect the predicates so that all unused
1647 // checks and uncommon_traps will be eliminated from the ideal graph
1648 void Compile::cleanup_loop_predicates(PhaseIterGVN &igvn) {
1649   if (predicate_count()==0) return;
1650   for (int i = predicate_count(); i > 0; i--) {
1651     Node * n = predicate_opaque1_node(i-1);
1652     assert(n->Opcode() == Op_Opaque1, "must be");
1653     igvn.replace_node(n, n->in(1));
1654   }
1655   assert(predicate_count()==0, "should be clean!");
1656 }
1657 
1658 //------------------------------Optimize---------------------------------------
1659 // Given a graph, optimize it.
1660 void Compile::Optimize() {
1661   TracePhase t1("optimizer", &_t_optimizer, true);
1662 
1663 #ifndef PRODUCT
1664   if (env()->break_at_compile()) {
1665     BREAKPOINT;
1666   }
1667 
1668 #endif
1669 
1670   ResourceMark rm;
1671   int          loop_opts_cnt;
1672 
1673   NOT_PRODUCT( verify_graph_edges(); )
1674 
1675   print_method("After Parsing");
1676 
1677  {
1678   // Iterative Global Value Numbering, including ideal transforms
1679   // Initialize IterGVN with types and values from parse-time GVN
1680   PhaseIterGVN igvn(initial_gvn());
1681   {
1682     NOT_PRODUCT( TracePhase t2("iterGVN", &_t_iterGVN, TimeCompiler); )
1683     igvn.optimize();
1684   }
1685 
1686   print_method("Iter GVN 1", 2);
1687 
1688   if (failing())  return;
1689 
1690   // Perform escape analysis
1691   if (_do_escape_analysis && ConnectionGraph::has_candidates(this)) {
1692     TracePhase t2("escapeAnalysis", &_t_escapeAnalysis, true);
1693     ConnectionGraph::do_analysis(this, &igvn);
1694 
1695     if (failing())  return;
1696 
1697     igvn.optimize();
1698     print_method("Iter GVN 3", 2);
1699 
1700     if (failing())  return;
1701 
1702   }
1703 
1704   // Loop transforms on the ideal graph.  Range Check Elimination,
1705   // peeling, unrolling, etc.
1706 
1707   // Set loop opts counter
1708   loop_opts_cnt = num_loop_opts();
1709   if((loop_opts_cnt > 0) && (has_loops() || has_split_ifs())) {
1710     {
1711       TracePhase t2("idealLoop", &_t_idealLoop, true);
1712       PhaseIdealLoop ideal_loop( igvn, true );
1713       loop_opts_cnt--;
1714       if (major_progress()) print_method("PhaseIdealLoop 1", 2);
1715       if (failing())  return;
1716     }
1717     // Loop opts pass if partial peeling occurred in previous pass
1718     if(PartialPeelLoop && major_progress() && (loop_opts_cnt > 0)) {
1719       TracePhase t3("idealLoop", &_t_idealLoop, true);
1720       PhaseIdealLoop ideal_loop( igvn, false );
1721       loop_opts_cnt--;
1722       if (major_progress()) print_method("PhaseIdealLoop 2", 2);
1723       if (failing())  return;
1724     }
1725     // Loop opts pass for loop-unrolling before CCP
1726     if(major_progress() && (loop_opts_cnt > 0)) {
1727       TracePhase t4("idealLoop", &_t_idealLoop, true);
1728       PhaseIdealLoop ideal_loop( igvn, false );
1729       loop_opts_cnt--;
1730       if (major_progress()) print_method("PhaseIdealLoop 3", 2);
1731     }
1732     if (!failing()) {
1733       // Verify that last round of loop opts produced a valid graph
1734       NOT_PRODUCT( TracePhase t2("idealLoopVerify", &_t_idealLoopVerify, TimeCompiler); )
1735       PhaseIdealLoop::verify(igvn);
1736     }
1737   }
1738   if (failing())  return;
1739 
1740   // Conditional Constant Propagation;
1741   PhaseCCP ccp( &igvn );
1742   assert( true, "Break here to ccp.dump_nodes_and_types(_root,999,1)");
1743   {
1744     TracePhase t2("ccp", &_t_ccp, true);
1745     ccp.do_transform();
1746   }
1747   print_method("PhaseCPP 1", 2);
1748 
1749   assert( true, "Break here to ccp.dump_old2new_map()");
1750 
1751   // Iterative Global Value Numbering, including ideal transforms
1752   {
1753     NOT_PRODUCT( TracePhase t2("iterGVN2", &_t_iterGVN2, TimeCompiler); )
1754     igvn = ccp;
1755     igvn.optimize();
1756   }
1757 
1758   print_method("Iter GVN 2", 2);
1759 
1760   if (failing())  return;
1761 
1762   // Loop transforms on the ideal graph.  Range Check Elimination,
1763   // peeling, unrolling, etc.
1764   if(loop_opts_cnt > 0) {
1765     debug_only( int cnt = 0; );
1766     while(major_progress() && (loop_opts_cnt > 0)) {
1767       TracePhase t2("idealLoop", &_t_idealLoop, true);
1768       assert( cnt++ < 40, "infinite cycle in loop optimization" );
1769       PhaseIdealLoop ideal_loop( igvn, true);
1770       loop_opts_cnt--;
1771       if (major_progress()) print_method("PhaseIdealLoop iterations", 2);
1772       if (failing())  return;
1773     }
1774   }
1775 
1776   {
1777     // Verify that all previous optimizations produced a valid graph
1778     // at least to this point, even if no loop optimizations were done.
1779     NOT_PRODUCT( TracePhase t2("idealLoopVerify", &_t_idealLoopVerify, TimeCompiler); )
1780     PhaseIdealLoop::verify(igvn);
1781   }
1782 
1783   {
1784     NOT_PRODUCT( TracePhase t2("macroExpand", &_t_macroExpand, TimeCompiler); )
1785     PhaseMacroExpand  mex(igvn);
1786     if (mex.expand_macro_nodes()) {
1787       assert(failing(), "must bail out w/ explicit message");
1788       return;
1789     }
1790   }
1791 
1792  } // (End scope of igvn; run destructor if necessary for asserts.)
1793 
1794   // A method with only infinite loops has no edges entering loops from root
1795   {
1796     NOT_PRODUCT( TracePhase t2("graphReshape", &_t_graphReshaping, TimeCompiler); )
1797     if (final_graph_reshaping()) {
1798       assert(failing(), "must bail out w/ explicit message");
1799       return;
1800     }
1801   }
1802 
1803   print_method("Optimize finished", 2);
1804 }
1805 
1806 
1807 //------------------------------Code_Gen---------------------------------------
1808 // Given a graph, generate code for it
1809 void Compile::Code_Gen() {
1810   if (failing())  return;
1811 
1812   // Perform instruction selection.  You might think we could reclaim Matcher
1813   // memory PDQ, but actually the Matcher is used in generating spill code.
1814   // Internals of the Matcher (including some VectorSets) must remain live
1815   // for awhile - thus I cannot reclaim Matcher memory lest a VectorSet usage
1816   // set a bit in reclaimed memory.
1817 
1818   // In debug mode can dump m._nodes.dump() for mapping of ideal to machine
1819   // nodes.  Mapping is only valid at the root of each matched subtree.
1820   NOT_PRODUCT( verify_graph_edges(); )
1821 
1822   Node_List proj_list;
1823   Matcher m(proj_list);
1824   _matcher = &m;
1825   {
1826     TracePhase t2("matcher", &_t_matcher, true);
1827     m.match();
1828   }
1829   // In debug mode can dump m._nodes.dump() for mapping of ideal to machine
1830   // nodes.  Mapping is only valid at the root of each matched subtree.
1831   NOT_PRODUCT( verify_graph_edges(); )
1832 
1833   // If you have too many nodes, or if matching has failed, bail out
1834   check_node_count(0, "out of nodes matching instructions");
1835   if (failing())  return;
1836 
1837   // Build a proper-looking CFG
1838   PhaseCFG cfg(node_arena(), root(), m);
1839   _cfg = &cfg;
1840   {
1841     NOT_PRODUCT( TracePhase t2("scheduler", &_t_scheduler, TimeCompiler); )
1842     cfg.Dominators();
1843     if (failing())  return;
1844 
1845     NOT_PRODUCT( verify_graph_edges(); )
1846 
1847     cfg.Estimate_Block_Frequency();
1848     cfg.GlobalCodeMotion(m,unique(),proj_list);
1849 
1850     print_method("Global code motion", 2);
1851 
1852     if (failing())  return;
1853     NOT_PRODUCT( verify_graph_edges(); )
1854 
1855     debug_only( cfg.verify(); )
1856   }
1857   NOT_PRODUCT( verify_graph_edges(); )
1858 
1859   PhaseChaitin regalloc(unique(),cfg,m);
1860   _regalloc = &regalloc;
1861   {
1862     TracePhase t2("regalloc", &_t_registerAllocation, true);
1863     // Perform any platform dependent preallocation actions.  This is used,
1864     // for example, to avoid taking an implicit null pointer exception
1865     // using the frame pointer on win95.
1866     _regalloc->pd_preallocate_hook();
1867 
1868     // Perform register allocation.  After Chaitin, use-def chains are
1869     // no longer accurate (at spill code) and so must be ignored.
1870     // Node->LRG->reg mappings are still accurate.
1871     _regalloc->Register_Allocate();
1872 
1873     // Bail out if the allocator builds too many nodes
1874     if (failing())  return;
1875   }
1876 
1877   // Prior to register allocation we kept empty basic blocks in case the
1878   // the allocator needed a place to spill.  After register allocation we
1879   // are not adding any new instructions.  If any basic block is empty, we
1880   // can now safely remove it.
1881   {
1882     NOT_PRODUCT( TracePhase t2("blockOrdering", &_t_blockOrdering, TimeCompiler); )
1883     cfg.remove_empty();
1884     if (do_freq_based_layout()) {
1885       PhaseBlockLayout layout(cfg);
1886     } else {
1887       cfg.set_loop_alignment();
1888     }
1889     cfg.fixup_flow();
1890   }
1891 
1892   // Perform any platform dependent postallocation verifications.
1893   debug_only( _regalloc->pd_postallocate_verify_hook(); )
1894 
1895   // Apply peephole optimizations
1896   if( OptoPeephole ) {
1897     NOT_PRODUCT( TracePhase t2("peephole", &_t_peephole, TimeCompiler); )
1898     PhasePeephole peep( _regalloc, cfg);
1899     peep.do_transform();
1900   }
1901 
1902   // Convert Nodes to instruction bits in a buffer
1903   {
1904     // %%%% workspace merge brought two timers together for one job
1905     TracePhase t2a("output", &_t_output, true);
1906     NOT_PRODUCT( TraceTime t2b(NULL, &_t_codeGeneration, TimeCompiler, false); )
1907     Output();
1908   }
1909 
1910   print_method("Final Code");
1911 
1912   // He's dead, Jim.
1913   _cfg     = (PhaseCFG*)0xdeadbeef;
1914   _regalloc = (PhaseChaitin*)0xdeadbeef;
1915 }
1916 
1917 
1918 //------------------------------dump_asm---------------------------------------
1919 // Dump formatted assembly
1920 #ifndef PRODUCT
1921 void Compile::dump_asm(int *pcs, uint pc_limit) {
1922   bool cut_short = false;
1923   tty->print_cr("#");
1924   tty->print("#  ");  _tf->dump();  tty->cr();
1925   tty->print_cr("#");
1926 
1927   // For all blocks
1928   int pc = 0x0;                 // Program counter
1929   char starts_bundle = ' ';
1930   _regalloc->dump_frame();
1931 
1932   Node *n = NULL;
1933   for( uint i=0; i<_cfg->_num_blocks; i++ ) {
1934     if (VMThread::should_terminate()) { cut_short = true; break; }
1935     Block *b = _cfg->_blocks[i];
1936     if (b->is_connector() && !Verbose) continue;
1937     n = b->_nodes[0];
1938     if (pcs && n->_idx < pc_limit)
1939       tty->print("%3.3x   ", pcs[n->_idx]);
1940     else
1941       tty->print("      ");
1942     b->dump_head( &_cfg->_bbs );
1943     if (b->is_connector()) {
1944       tty->print_cr("        # Empty connector block");
1945     } else if (b->num_preds() == 2 && b->pred(1)->is_CatchProj() && b->pred(1)->as_CatchProj()->_con == CatchProjNode::fall_through_index) {
1946       tty->print_cr("        # Block is sole successor of call");
1947     }
1948 
1949     // For all instructions
1950     Node *delay = NULL;
1951     for( uint j = 0; j<b->_nodes.size(); j++ ) {
1952       if (VMThread::should_terminate()) { cut_short = true; break; }
1953       n = b->_nodes[j];
1954       if (valid_bundle_info(n)) {
1955         Bundle *bundle = node_bundling(n);
1956         if (bundle->used_in_unconditional_delay()) {
1957           delay = n;
1958           continue;
1959         }
1960         if (bundle->starts_bundle())
1961           starts_bundle = '+';
1962       }
1963 
1964       if (WizardMode) n->dump();
1965 
1966       if( !n->is_Region() &&    // Dont print in the Assembly
1967           !n->is_Phi() &&       // a few noisely useless nodes
1968           !n->is_Proj() &&
1969           !n->is_MachTemp() &&
1970           !n->is_SafePointScalarObject() &&
1971           !n->is_Catch() &&     // Would be nice to print exception table targets
1972           !n->is_MergeMem() &&  // Not very interesting
1973           !n->is_top() &&       // Debug info table constants
1974           !(n->is_Con() && !n->is_Mach())// Debug info table constants
1975           ) {
1976         if (pcs && n->_idx < pc_limit)
1977           tty->print("%3.3x", pcs[n->_idx]);
1978         else
1979           tty->print("   ");
1980         tty->print(" %c ", starts_bundle);
1981         starts_bundle = ' ';
1982         tty->print("\t");
1983         n->format(_regalloc, tty);
1984         tty->cr();
1985       }
1986 
1987       // If we have an instruction with a delay slot, and have seen a delay,
1988       // then back up and print it
1989       if (valid_bundle_info(n) && node_bundling(n)->use_unconditional_delay()) {
1990         assert(delay != NULL, "no unconditional delay instruction");
1991         if (WizardMode) delay->dump();
1992 
1993         if (node_bundling(delay)->starts_bundle())
1994           starts_bundle = '+';
1995         if (pcs && n->_idx < pc_limit)
1996           tty->print("%3.3x", pcs[n->_idx]);
1997         else
1998           tty->print("   ");
1999         tty->print(" %c ", starts_bundle);
2000         starts_bundle = ' ';
2001         tty->print("\t");
2002         delay->format(_regalloc, tty);
2003         tty->print_cr("");
2004         delay = NULL;
2005       }
2006 
2007       // Dump the exception table as well
2008       if( n->is_Catch() && (Verbose || WizardMode) ) {
2009         // Print the exception table for this offset
2010         _handler_table.print_subtable_for(pc);
2011       }
2012     }
2013 
2014     if (pcs && n->_idx < pc_limit)
2015       tty->print_cr("%3.3x", pcs[n->_idx]);
2016     else
2017       tty->print_cr("");
2018 
2019     assert(cut_short || delay == NULL, "no unconditional delay branch");
2020 
2021   } // End of per-block dump
2022   tty->print_cr("");
2023 
2024   if (cut_short)  tty->print_cr("*** disassembly is cut short ***");
2025 }
2026 #endif
2027 
2028 //------------------------------Final_Reshape_Counts---------------------------
2029 // This class defines counters to help identify when a method
2030 // may/must be executed using hardware with only 24-bit precision.
2031 struct Final_Reshape_Counts : public StackObj {
2032   int  _call_count;             // count non-inlined 'common' calls
2033   int  _float_count;            // count float ops requiring 24-bit precision
2034   int  _double_count;           // count double ops requiring more precision
2035   int  _java_call_count;        // count non-inlined 'java' calls
2036   int  _inner_loop_count;       // count loops which need alignment
2037   VectorSet _visited;           // Visitation flags
2038   Node_List _tests;             // Set of IfNodes & PCTableNodes
2039 
2040   Final_Reshape_Counts() :
2041     _call_count(0), _float_count(0), _double_count(0),
2042     _java_call_count(0), _inner_loop_count(0),
2043     _visited( Thread::current()->resource_area() ) { }
2044 
2045   void inc_call_count  () { _call_count  ++; }
2046   void inc_float_count () { _float_count ++; }
2047   void inc_double_count() { _double_count++; }
2048   void inc_java_call_count() { _java_call_count++; }
2049   void inc_inner_loop_count() { _inner_loop_count++; }
2050 
2051   int  get_call_count  () const { return _call_count  ; }
2052   int  get_float_count () const { return _float_count ; }
2053   int  get_double_count() const { return _double_count; }
2054   int  get_java_call_count() const { return _java_call_count; }
2055   int  get_inner_loop_count() const { return _inner_loop_count; }
2056 };
2057 
2058 static bool oop_offset_is_sane(const TypeInstPtr* tp) {
2059   ciInstanceKlass *k = tp->klass()->as_instance_klass();
2060   // Make sure the offset goes inside the instance layout.
2061   return k->contains_field_offset(tp->offset());
2062   // Note that OffsetBot and OffsetTop are very negative.
2063 }
2064 
2065 // Eliminate trivially redundant StoreCMs and accumulate their
2066 // precedence edges.
2067 static void eliminate_redundant_card_marks(Node* n) {
2068   assert(n->Opcode() == Op_StoreCM, "expected StoreCM");
2069   if (n->in(MemNode::Address)->outcnt() > 1) {
2070     // There are multiple users of the same address so it might be
2071     // possible to eliminate some of the StoreCMs
2072     Node* mem = n->in(MemNode::Memory);
2073     Node* adr = n->in(MemNode::Address);
2074     Node* val = n->in(MemNode::ValueIn);
2075     Node* prev = n;
2076     bool done = false;
2077     // Walk the chain of StoreCMs eliminating ones that match.  As
2078     // long as it's a chain of single users then the optimization is
2079     // safe.  Eliminating partially redundant StoreCMs would require
2080     // cloning copies down the other paths.
2081     while (mem->Opcode() == Op_StoreCM && mem->outcnt() == 1 && !done) {
2082       if (adr == mem->in(MemNode::Address) &&
2083           val == mem->in(MemNode::ValueIn)) {
2084         // redundant StoreCM
2085         if (mem->req() > MemNode::OopStore) {
2086           // Hasn't been processed by this code yet.
2087           n->add_prec(mem->in(MemNode::OopStore));
2088         } else {
2089           // Already converted to precedence edge
2090           for (uint i = mem->req(); i < mem->len(); i++) {
2091             // Accumulate any precedence edges
2092             if (mem->in(i) != NULL) {
2093               n->add_prec(mem->in(i));
2094             }
2095           }
2096           // Everything above this point has been processed.
2097           done = true;
2098         }
2099         // Eliminate the previous StoreCM
2100         prev->set_req(MemNode::Memory, mem->in(MemNode::Memory));
2101         assert(mem->outcnt() == 0, "should be dead");
2102         mem->disconnect_inputs(NULL);
2103       } else {
2104         prev = mem;
2105       }
2106       mem = prev->in(MemNode::Memory);
2107     }
2108   }
2109 }
2110 
2111 //------------------------------final_graph_reshaping_impl----------------------
2112 // Implement items 1-5 from final_graph_reshaping below.
2113 static void final_graph_reshaping_impl( Node *n, Final_Reshape_Counts &frc ) {
2114 
2115   if ( n->outcnt() == 0 ) return; // dead node
2116   uint nop = n->Opcode();
2117 
2118   // Check for 2-input instruction with "last use" on right input.
2119   // Swap to left input.  Implements item (2).
2120   if( n->req() == 3 &&          // two-input instruction
2121       n->in(1)->outcnt() > 1 && // left use is NOT a last use
2122       (!n->in(1)->is_Phi() || n->in(1)->in(2) != n) && // it is not data loop
2123       n->in(2)->outcnt() == 1 &&// right use IS a last use
2124       !n->in(2)->is_Con() ) {   // right use is not a constant
2125     // Check for commutative opcode
2126     switch( nop ) {
2127     case Op_AddI:  case Op_AddF:  case Op_AddD:  case Op_AddL:
2128     case Op_MaxI:  case Op_MinI:
2129     case Op_MulI:  case Op_MulF:  case Op_MulD:  case Op_MulL:
2130     case Op_AndL:  case Op_XorL:  case Op_OrL:
2131     case Op_AndI:  case Op_XorI:  case Op_OrI: {
2132       // Move "last use" input to left by swapping inputs
2133       n->swap_edges(1, 2);
2134       break;
2135     }
2136     default:
2137       break;
2138     }
2139   }
2140 
2141 #ifdef ASSERT
2142   if( n->is_Mem() ) {
2143     Compile* C = Compile::current();
2144     int alias_idx = C->get_alias_index(n->as_Mem()->adr_type());
2145     assert( n->in(0) != NULL || alias_idx != Compile::AliasIdxRaw ||
2146             // oop will be recorded in oop map if load crosses safepoint
2147             n->is_Load() && (n->as_Load()->bottom_type()->isa_oopptr() ||
2148                              LoadNode::is_immutable_value(n->in(MemNode::Address))),
2149             "raw memory operations should have control edge");
2150   }
2151 #endif
2152   // Count FPU ops and common calls, implements item (3)
2153   switch( nop ) {
2154   // Count all float operations that may use FPU
2155   case Op_AddF:
2156   case Op_SubF:
2157   case Op_MulF:
2158   case Op_DivF:
2159   case Op_NegF:
2160   case Op_ModF:
2161   case Op_ConvI2F:
2162   case Op_ConF:
2163   case Op_CmpF:
2164   case Op_CmpF3:
2165   // case Op_ConvL2F: // longs are split into 32-bit halves
2166     frc.inc_float_count();
2167     break;
2168 
2169   case Op_ConvF2D:
2170   case Op_ConvD2F:
2171     frc.inc_float_count();
2172     frc.inc_double_count();
2173     break;
2174 
2175   // Count all double operations that may use FPU
2176   case Op_AddD:
2177   case Op_SubD:
2178   case Op_MulD:
2179   case Op_DivD:
2180   case Op_NegD:
2181   case Op_ModD:
2182   case Op_ConvI2D:
2183   case Op_ConvD2I:
2184   // case Op_ConvL2D: // handled by leaf call
2185   // case Op_ConvD2L: // handled by leaf call
2186   case Op_ConD:
2187   case Op_CmpD:
2188   case Op_CmpD3:
2189     frc.inc_double_count();
2190     break;
2191   case Op_Opaque1:              // Remove Opaque Nodes before matching
2192   case Op_Opaque2:              // Remove Opaque Nodes before matching
2193     n->subsume_by(n->in(1));
2194     break;
2195   case Op_CallStaticJava:
2196   case Op_CallJava:
2197   case Op_CallDynamicJava:
2198     frc.inc_java_call_count(); // Count java call site;
2199   case Op_CallRuntime:
2200   case Op_CallLeaf:
2201   case Op_CallLeafNoFP: {
2202     assert( n->is_Call(), "" );
2203     CallNode *call = n->as_Call();
2204     // Count call sites where the FP mode bit would have to be flipped.
2205     // Do not count uncommon runtime calls:
2206     // uncommon_trap, _complete_monitor_locking, _complete_monitor_unlocking,
2207     // _new_Java, _new_typeArray, _new_objArray, _rethrow_Java, ...
2208     if( !call->is_CallStaticJava() || !call->as_CallStaticJava()->_name ) {
2209       frc.inc_call_count();   // Count the call site
2210     } else {                  // See if uncommon argument is shared
2211       Node *n = call->in(TypeFunc::Parms);
2212       int nop = n->Opcode();
2213       // Clone shared simple arguments to uncommon calls, item (1).
2214       if( n->outcnt() > 1 &&
2215           !n->is_Proj() &&
2216           nop != Op_CreateEx &&
2217           nop != Op_CheckCastPP &&
2218           nop != Op_DecodeN &&
2219           !n->is_Mem() ) {
2220         Node *x = n->clone();
2221         call->set_req( TypeFunc::Parms, x );
2222       }
2223     }
2224     break;
2225   }
2226 
2227   case Op_StoreD:
2228   case Op_LoadD:
2229   case Op_LoadD_unaligned:
2230     frc.inc_double_count();
2231     goto handle_mem;
2232   case Op_StoreF:
2233   case Op_LoadF:
2234     frc.inc_float_count();
2235     goto handle_mem;
2236 
2237   case Op_StoreCM:
2238     {
2239       // Convert OopStore dependence into precedence edge
2240       Node* prec = n->in(MemNode::OopStore);
2241       n->del_req(MemNode::OopStore);
2242       n->add_prec(prec);
2243       eliminate_redundant_card_marks(n);
2244     }
2245 
2246     // fall through
2247 
2248   case Op_StoreB:
2249   case Op_StoreC:
2250   case Op_StorePConditional:
2251   case Op_StoreI:
2252   case Op_StoreL:
2253   case Op_StoreIConditional:
2254   case Op_StoreLConditional:
2255   case Op_CompareAndSwapI:
2256   case Op_CompareAndSwapL:
2257   case Op_CompareAndSwapP:
2258   case Op_CompareAndSwapN:
2259   case Op_StoreP:
2260   case Op_StoreN:
2261   case Op_LoadB:
2262   case Op_LoadUB:
2263   case Op_LoadUS:
2264   case Op_LoadI:
2265   case Op_LoadUI2L:
2266   case Op_LoadKlass:
2267   case Op_LoadNKlass:
2268   case Op_LoadL:
2269   case Op_LoadL_unaligned:
2270   case Op_LoadPLocked:
2271   case Op_LoadLLocked:
2272   case Op_LoadP:
2273   case Op_LoadN:
2274   case Op_LoadRange:
2275   case Op_LoadS: {
2276   handle_mem:
2277 #ifdef ASSERT
2278     if( VerifyOptoOopOffsets ) {
2279       assert( n->is_Mem(), "" );
2280       MemNode *mem  = (MemNode*)n;
2281       // Check to see if address types have grounded out somehow.
2282       const TypeInstPtr *tp = mem->in(MemNode::Address)->bottom_type()->isa_instptr();
2283       assert( !tp || oop_offset_is_sane(tp), "" );
2284     }
2285 #endif
2286     break;
2287   }
2288 
2289   case Op_AddP: {               // Assert sane base pointers
2290     Node *addp = n->in(AddPNode::Address);
2291     assert( !addp->is_AddP() ||
2292             addp->in(AddPNode::Base)->is_top() || // Top OK for allocation
2293             addp->in(AddPNode::Base) == n->in(AddPNode::Base),
2294             "Base pointers must match" );
2295 #ifdef _LP64
2296     if (UseCompressedOops &&
2297         addp->Opcode() == Op_ConP &&
2298         addp == n->in(AddPNode::Base) &&
2299         n->in(AddPNode::Offset)->is_Con()) {
2300       // Use addressing with narrow klass to load with offset on x86.
2301       // On sparc loading 32-bits constant and decoding it have less
2302       // instructions (4) then load 64-bits constant (7).
2303       // Do this transformation here since IGVN will convert ConN back to ConP.
2304       const Type* t = addp->bottom_type();
2305       if (t->isa_oopptr()) {
2306         Node* nn = NULL;
2307 
2308         // Look for existing ConN node of the same exact type.
2309         Compile* C = Compile::current();
2310         Node* r  = C->root();
2311         uint cnt = r->outcnt();
2312         for (uint i = 0; i < cnt; i++) {
2313           Node* m = r->raw_out(i);
2314           if (m!= NULL && m->Opcode() == Op_ConN &&
2315               m->bottom_type()->make_ptr() == t) {
2316             nn = m;
2317             break;
2318           }
2319         }
2320         if (nn != NULL) {
2321           // Decode a narrow oop to match address
2322           // [R12 + narrow_oop_reg<<3 + offset]
2323           nn = new (C,  2) DecodeNNode(nn, t);
2324           n->set_req(AddPNode::Base, nn);
2325           n->set_req(AddPNode::Address, nn);
2326           if (addp->outcnt() == 0) {
2327             addp->disconnect_inputs(NULL);
2328           }
2329         }
2330       }
2331     }
2332 #endif
2333     break;
2334   }
2335 
2336 #ifdef _LP64
2337   case Op_CastPP:
2338     if (n->in(1)->is_DecodeN() && Matcher::gen_narrow_oop_implicit_null_checks()) {
2339       Compile* C = Compile::current();
2340       Node* in1 = n->in(1);
2341       const Type* t = n->bottom_type();
2342       Node* new_in1 = in1->clone();
2343       new_in1->as_DecodeN()->set_type(t);
2344 
2345       if (!Matcher::narrow_oop_use_complex_address()) {
2346         //
2347         // x86, ARM and friends can handle 2 adds in addressing mode
2348         // and Matcher can fold a DecodeN node into address by using
2349         // a narrow oop directly and do implicit NULL check in address:
2350         //
2351         // [R12 + narrow_oop_reg<<3 + offset]
2352         // NullCheck narrow_oop_reg
2353         //
2354         // On other platforms (Sparc) we have to keep new DecodeN node and
2355         // use it to do implicit NULL check in address:
2356         //
2357         // decode_not_null narrow_oop_reg, base_reg
2358         // [base_reg + offset]
2359         // NullCheck base_reg
2360         //
2361         // Pin the new DecodeN node to non-null path on these platform (Sparc)
2362         // to keep the information to which NULL check the new DecodeN node
2363         // corresponds to use it as value in implicit_null_check().
2364         //
2365         new_in1->set_req(0, n->in(0));
2366       }
2367 
2368       n->subsume_by(new_in1);
2369       if (in1->outcnt() == 0) {
2370         in1->disconnect_inputs(NULL);
2371       }
2372     }
2373     break;
2374 
2375   case Op_CmpP:
2376     // Do this transformation here to preserve CmpPNode::sub() and
2377     // other TypePtr related Ideal optimizations (for example, ptr nullness).
2378     if (n->in(1)->is_DecodeN() || n->in(2)->is_DecodeN()) {
2379       Node* in1 = n->in(1);
2380       Node* in2 = n->in(2);
2381       if (!in1->is_DecodeN()) {
2382         in2 = in1;
2383         in1 = n->in(2);
2384       }
2385       assert(in1->is_DecodeN(), "sanity");
2386 
2387       Compile* C = Compile::current();
2388       Node* new_in2 = NULL;
2389       if (in2->is_DecodeN()) {
2390         new_in2 = in2->in(1);
2391       } else if (in2->Opcode() == Op_ConP) {
2392         const Type* t = in2->bottom_type();
2393         if (t == TypePtr::NULL_PTR) {
2394           // Don't convert CmpP null check into CmpN if compressed
2395           // oops implicit null check is not generated.
2396           // This will allow to generate normal oop implicit null check.
2397           if (Matcher::gen_narrow_oop_implicit_null_checks())
2398             new_in2 = ConNode::make(C, TypeNarrowOop::NULL_PTR);
2399           //
2400           // This transformation together with CastPP transformation above
2401           // will generated code for implicit NULL checks for compressed oops.
2402           //
2403           // The original code after Optimize()
2404           //
2405           //    LoadN memory, narrow_oop_reg
2406           //    decode narrow_oop_reg, base_reg
2407           //    CmpP base_reg, NULL
2408           //    CastPP base_reg // NotNull
2409           //    Load [base_reg + offset], val_reg
2410           //
2411           // after these transformations will be
2412           //
2413           //    LoadN memory, narrow_oop_reg
2414           //    CmpN narrow_oop_reg, NULL
2415           //    decode_not_null narrow_oop_reg, base_reg
2416           //    Load [base_reg + offset], val_reg
2417           //
2418           // and the uncommon path (== NULL) will use narrow_oop_reg directly
2419           // since narrow oops can be used in debug info now (see the code in
2420           // final_graph_reshaping_walk()).
2421           //
2422           // At the end the code will be matched to
2423           // on x86:
2424           //
2425           //    Load_narrow_oop memory, narrow_oop_reg
2426           //    Load [R12 + narrow_oop_reg<<3 + offset], val_reg
2427           //    NullCheck narrow_oop_reg
2428           //
2429           // and on sparc:
2430           //
2431           //    Load_narrow_oop memory, narrow_oop_reg
2432           //    decode_not_null narrow_oop_reg, base_reg
2433           //    Load [base_reg + offset], val_reg
2434           //    NullCheck base_reg
2435           //
2436         } else if (t->isa_oopptr()) {
2437           new_in2 = ConNode::make(C, t->make_narrowoop());
2438         }
2439       }
2440       if (new_in2 != NULL) {
2441         Node* cmpN = new (C, 3) CmpNNode(in1->in(1), new_in2);
2442         n->subsume_by( cmpN );
2443         if (in1->outcnt() == 0) {
2444           in1->disconnect_inputs(NULL);
2445         }
2446         if (in2->outcnt() == 0) {
2447           in2->disconnect_inputs(NULL);
2448         }
2449       }
2450     }
2451     break;
2452 
2453   case Op_DecodeN:
2454     assert(!n->in(1)->is_EncodeP(), "should be optimized out");
2455     // DecodeN could be pinned when it can't be fold into
2456     // an address expression, see the code for Op_CastPP above.
2457     assert(n->in(0) == NULL || !Matcher::narrow_oop_use_complex_address(), "no control");
2458     break;
2459 
2460   case Op_EncodeP: {
2461     Node* in1 = n->in(1);
2462     if (in1->is_DecodeN()) {
2463       n->subsume_by(in1->in(1));
2464     } else if (in1->Opcode() == Op_ConP) {
2465       Compile* C = Compile::current();
2466       const Type* t = in1->bottom_type();
2467       if (t == TypePtr::NULL_PTR) {
2468         n->subsume_by(ConNode::make(C, TypeNarrowOop::NULL_PTR));
2469       } else if (t->isa_oopptr()) {
2470         n->subsume_by(ConNode::make(C, t->make_narrowoop()));
2471       }
2472     }
2473     if (in1->outcnt() == 0) {
2474       in1->disconnect_inputs(NULL);
2475     }
2476     break;
2477   }
2478 
2479   case Op_Proj: {
2480     if (OptimizeStringConcat) {
2481       ProjNode* p = n->as_Proj();
2482       if (p->_is_io_use) {
2483         // Separate projections were used for the exception path which
2484         // are normally removed by a late inline.  If it wasn't inlined
2485         // then they will hang around and should just be replaced with
2486         // the original one.
2487         Node* proj = NULL;
2488         // Replace with just one
2489         for (SimpleDUIterator i(p->in(0)); i.has_next(); i.next()) {
2490           Node *use = i.get();
2491           if (use->is_Proj() && p != use && use->as_Proj()->_con == p->_con) {
2492             proj = use;
2493             break;
2494           }
2495         }
2496         assert(p != NULL, "must be found");
2497         p->subsume_by(proj);
2498       }
2499     }
2500     break;
2501   }
2502 
2503   case Op_Phi:
2504     if (n->as_Phi()->bottom_type()->isa_narrowoop()) {
2505       // The EncodeP optimization may create Phi with the same edges
2506       // for all paths. It is not handled well by Register Allocator.
2507       Node* unique_in = n->in(1);
2508       assert(unique_in != NULL, "");
2509       uint cnt = n->req();
2510       for (uint i = 2; i < cnt; i++) {
2511         Node* m = n->in(i);
2512         assert(m != NULL, "");
2513         if (unique_in != m)
2514           unique_in = NULL;
2515       }
2516       if (unique_in != NULL) {
2517         n->subsume_by(unique_in);
2518       }
2519     }
2520     break;
2521 
2522 #endif
2523 
2524   case Op_ModI:
2525     if (UseDivMod) {
2526       // Check if a%b and a/b both exist
2527       Node* d = n->find_similar(Op_DivI);
2528       if (d) {
2529         // Replace them with a fused divmod if supported
2530         Compile* C = Compile::current();
2531         if (Matcher::has_match_rule(Op_DivModI)) {
2532           DivModINode* divmod = DivModINode::make(C, n);
2533           d->subsume_by(divmod->div_proj());
2534           n->subsume_by(divmod->mod_proj());
2535         } else {
2536           // replace a%b with a-((a/b)*b)
2537           Node* mult = new (C, 3) MulINode(d, d->in(2));
2538           Node* sub  = new (C, 3) SubINode(d->in(1), mult);
2539           n->subsume_by( sub );
2540         }
2541       }
2542     }
2543     break;
2544 
2545   case Op_ModL:
2546     if (UseDivMod) {
2547       // Check if a%b and a/b both exist
2548       Node* d = n->find_similar(Op_DivL);
2549       if (d) {
2550         // Replace them with a fused divmod if supported
2551         Compile* C = Compile::current();
2552         if (Matcher::has_match_rule(Op_DivModL)) {
2553           DivModLNode* divmod = DivModLNode::make(C, n);
2554           d->subsume_by(divmod->div_proj());
2555           n->subsume_by(divmod->mod_proj());
2556         } else {
2557           // replace a%b with a-((a/b)*b)
2558           Node* mult = new (C, 3) MulLNode(d, d->in(2));
2559           Node* sub  = new (C, 3) SubLNode(d->in(1), mult);
2560           n->subsume_by( sub );
2561         }
2562       }
2563     }
2564     break;
2565 
2566   case Op_Load16B:
2567   case Op_Load8B:
2568   case Op_Load4B:
2569   case Op_Load8S:
2570   case Op_Load4S:
2571   case Op_Load2S:
2572   case Op_Load8C:
2573   case Op_Load4C:
2574   case Op_Load2C:
2575   case Op_Load4I:
2576   case Op_Load2I:
2577   case Op_Load2L:
2578   case Op_Load4F:
2579   case Op_Load2F:
2580   case Op_Load2D:
2581   case Op_Store16B:
2582   case Op_Store8B:
2583   case Op_Store4B:
2584   case Op_Store8C:
2585   case Op_Store4C:
2586   case Op_Store2C:
2587   case Op_Store4I:
2588   case Op_Store2I:
2589   case Op_Store2L:
2590   case Op_Store4F:
2591   case Op_Store2F:
2592   case Op_Store2D:
2593     break;
2594 
2595   case Op_PackB:
2596   case Op_PackS:
2597   case Op_PackC:
2598   case Op_PackI:
2599   case Op_PackF:
2600   case Op_PackL:
2601   case Op_PackD:
2602     if (n->req()-1 > 2) {
2603       // Replace many operand PackNodes with a binary tree for matching
2604       PackNode* p = (PackNode*) n;
2605       Node* btp = p->binaryTreePack(Compile::current(), 1, n->req());
2606       n->subsume_by(btp);
2607     }
2608     break;
2609   case Op_Loop:
2610   case Op_CountedLoop:
2611     if (n->as_Loop()->is_inner_loop()) {
2612       frc.inc_inner_loop_count();
2613     }
2614     break;
2615   case Op_LShiftI:
2616   case Op_RShiftI:
2617   case Op_URShiftI:
2618   case Op_LShiftL:
2619   case Op_RShiftL:
2620   case Op_URShiftL:
2621     if (Matcher::need_masked_shift_count) {
2622       // The cpu's shift instructions don't restrict the count to the
2623       // lower 5/6 bits. We need to do the masking ourselves.
2624       Node* in2 = n->in(2);
2625       juint mask = (n->bottom_type() == TypeInt::INT) ? (BitsPerInt - 1) : (BitsPerLong - 1);
2626       const TypeInt* t = in2->find_int_type();
2627       if (t != NULL && t->is_con()) {
2628         juint shift = t->get_con();
2629         if (shift > mask) { // Unsigned cmp
2630           Compile* C = Compile::current();
2631           n->set_req(2, ConNode::make(C, TypeInt::make(shift & mask)));
2632         }
2633       } else {
2634         if (t == NULL || t->_lo < 0 || t->_hi > (int)mask) {
2635           Compile* C = Compile::current();
2636           Node* shift = new (C, 3) AndINode(in2, ConNode::make(C, TypeInt::make(mask)));
2637           n->set_req(2, shift);
2638         }
2639       }
2640       if (in2->outcnt() == 0) { // Remove dead node
2641         in2->disconnect_inputs(NULL);
2642       }
2643     }
2644     break;
2645   default:
2646     assert( !n->is_Call(), "" );
2647     assert( !n->is_Mem(), "" );
2648     break;
2649   }
2650 
2651   // Collect CFG split points
2652   if (n->is_MultiBranch())
2653     frc._tests.push(n);
2654 }
2655 
2656 //------------------------------final_graph_reshaping_walk---------------------
2657 // Replacing Opaque nodes with their input in final_graph_reshaping_impl(),
2658 // requires that the walk visits a node's inputs before visiting the node.
2659 static void final_graph_reshaping_walk( Node_Stack &nstack, Node *root, Final_Reshape_Counts &frc ) {
2660   ResourceArea *area = Thread::current()->resource_area();
2661   Unique_Node_List sfpt(area);
2662 
2663   frc._visited.set(root->_idx); // first, mark node as visited
2664   uint cnt = root->req();
2665   Node *n = root;
2666   uint  i = 0;
2667   while (true) {
2668     if (i < cnt) {
2669       // Place all non-visited non-null inputs onto stack
2670       Node* m = n->in(i);
2671       ++i;
2672       if (m != NULL && !frc._visited.test_set(m->_idx)) {
2673         if (m->is_SafePoint() && m->as_SafePoint()->jvms() != NULL)
2674           sfpt.push(m);
2675         cnt = m->req();
2676         nstack.push(n, i); // put on stack parent and next input's index
2677         n = m;
2678         i = 0;
2679       }
2680     } else {
2681       // Now do post-visit work
2682       final_graph_reshaping_impl( n, frc );
2683       if (nstack.is_empty())
2684         break;             // finished
2685       n = nstack.node();   // Get node from stack
2686       cnt = n->req();
2687       i = nstack.index();
2688       nstack.pop();        // Shift to the next node on stack
2689     }
2690   }
2691 
2692   // Skip next transformation if compressed oops are not used.
2693   if (!UseCompressedOops || !Matcher::gen_narrow_oop_implicit_null_checks())
2694     return;
2695 
2696   // Go over safepoints nodes to skip DecodeN nodes for debug edges.
2697   // It could be done for an uncommon traps or any safepoints/calls
2698   // if the DecodeN node is referenced only in a debug info.
2699   while (sfpt.size() > 0) {
2700     n = sfpt.pop();
2701     JVMState *jvms = n->as_SafePoint()->jvms();
2702     assert(jvms != NULL, "sanity");
2703     int start = jvms->debug_start();
2704     int end   = n->req();
2705     bool is_uncommon = (n->is_CallStaticJava() &&
2706                         n->as_CallStaticJava()->uncommon_trap_request() != 0);
2707     for (int j = start; j < end; j++) {
2708       Node* in = n->in(j);
2709       if (in->is_DecodeN()) {
2710         bool safe_to_skip = true;
2711         if (!is_uncommon ) {
2712           // Is it safe to skip?
2713           for (uint i = 0; i < in->outcnt(); i++) {
2714             Node* u = in->raw_out(i);
2715             if (!u->is_SafePoint() ||
2716                  u->is_Call() && u->as_Call()->has_non_debug_use(n)) {
2717               safe_to_skip = false;
2718             }
2719           }
2720         }
2721         if (safe_to_skip) {
2722           n->set_req(j, in->in(1));
2723         }
2724         if (in->outcnt() == 0) {
2725           in->disconnect_inputs(NULL);
2726         }
2727       }
2728     }
2729   }
2730 }
2731 
2732 //------------------------------final_graph_reshaping--------------------------
2733 // Final Graph Reshaping.
2734 //
2735 // (1) Clone simple inputs to uncommon calls, so they can be scheduled late
2736 //     and not commoned up and forced early.  Must come after regular
2737 //     optimizations to avoid GVN undoing the cloning.  Clone constant
2738 //     inputs to Loop Phis; these will be split by the allocator anyways.
2739 //     Remove Opaque nodes.
2740 // (2) Move last-uses by commutative operations to the left input to encourage
2741 //     Intel update-in-place two-address operations and better register usage
2742 //     on RISCs.  Must come after regular optimizations to avoid GVN Ideal
2743 //     calls canonicalizing them back.
2744 // (3) Count the number of double-precision FP ops, single-precision FP ops
2745 //     and call sites.  On Intel, we can get correct rounding either by
2746 //     forcing singles to memory (requires extra stores and loads after each
2747 //     FP bytecode) or we can set a rounding mode bit (requires setting and
2748 //     clearing the mode bit around call sites).  The mode bit is only used
2749 //     if the relative frequency of single FP ops to calls is low enough.
2750 //     This is a key transform for SPEC mpeg_audio.
2751 // (4) Detect infinite loops; blobs of code reachable from above but not
2752 //     below.  Several of the Code_Gen algorithms fail on such code shapes,
2753 //     so we simply bail out.  Happens a lot in ZKM.jar, but also happens
2754 //     from time to time in other codes (such as -Xcomp finalizer loops, etc).
2755 //     Detection is by looking for IfNodes where only 1 projection is
2756 //     reachable from below or CatchNodes missing some targets.
2757 // (5) Assert for insane oop offsets in debug mode.
2758 
2759 bool Compile::final_graph_reshaping() {
2760   // an infinite loop may have been eliminated by the optimizer,
2761   // in which case the graph will be empty.
2762   if (root()->req() == 1) {
2763     record_method_not_compilable("trivial infinite loop");
2764     return true;
2765   }
2766 
2767   Final_Reshape_Counts frc;
2768 
2769   // Visit everybody reachable!
2770   // Allocate stack of size C->unique()/2 to avoid frequent realloc
2771   Node_Stack nstack(unique() >> 1);
2772   final_graph_reshaping_walk(nstack, root(), frc);
2773 
2774   // Check for unreachable (from below) code (i.e., infinite loops).
2775   for( uint i = 0; i < frc._tests.size(); i++ ) {
2776     MultiBranchNode *n = frc._tests[i]->as_MultiBranch();
2777     // Get number of CFG targets.
2778     // Note that PCTables include exception targets after calls.
2779     uint required_outcnt = n->required_outcnt();
2780     if (n->outcnt() != required_outcnt) {
2781       // Check for a few special cases.  Rethrow Nodes never take the
2782       // 'fall-thru' path, so expected kids is 1 less.
2783       if (n->is_PCTable() && n->in(0) && n->in(0)->in(0)) {
2784         if (n->in(0)->in(0)->is_Call()) {
2785           CallNode *call = n->in(0)->in(0)->as_Call();
2786           if (call->entry_point() == OptoRuntime::rethrow_stub()) {
2787             required_outcnt--;      // Rethrow always has 1 less kid
2788           } else if (call->req() > TypeFunc::Parms &&
2789                      call->is_CallDynamicJava()) {
2790             // Check for null receiver. In such case, the optimizer has
2791             // detected that the virtual call will always result in a null
2792             // pointer exception. The fall-through projection of this CatchNode
2793             // will not be populated.
2794             Node *arg0 = call->in(TypeFunc::Parms);
2795             if (arg0->is_Type() &&
2796                 arg0->as_Type()->type()->higher_equal(TypePtr::NULL_PTR)) {
2797               required_outcnt--;
2798             }
2799           } else if (call->entry_point() == OptoRuntime::new_array_Java() &&
2800                      call->req() > TypeFunc::Parms+1 &&
2801                      call->is_CallStaticJava()) {
2802             // Check for negative array length. In such case, the optimizer has
2803             // detected that the allocation attempt will always result in an
2804             // exception. There is no fall-through projection of this CatchNode .
2805             Node *arg1 = call->in(TypeFunc::Parms+1);
2806             if (arg1->is_Type() &&
2807                 arg1->as_Type()->type()->join(TypeInt::POS)->empty()) {
2808               required_outcnt--;
2809             }
2810           }
2811         }
2812       }
2813       // Recheck with a better notion of 'required_outcnt'
2814       if (n->outcnt() != required_outcnt) {
2815         record_method_not_compilable("malformed control flow");
2816         return true;            // Not all targets reachable!
2817       }
2818     }
2819     // Check that I actually visited all kids.  Unreached kids
2820     // must be infinite loops.
2821     for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++)
2822       if (!frc._visited.test(n->fast_out(j)->_idx)) {
2823         record_method_not_compilable("infinite loop");
2824         return true;            // Found unvisited kid; must be unreach
2825       }
2826   }
2827 
2828   // If original bytecodes contained a mixture of floats and doubles
2829   // check if the optimizer has made it homogenous, item (3).
2830   if( Use24BitFPMode && Use24BitFP && UseSSE == 0 &&
2831       frc.get_float_count() > 32 &&
2832       frc.get_double_count() == 0 &&
2833       (10 * frc.get_call_count() < frc.get_float_count()) ) {
2834     set_24_bit_selection_and_mode( false,  true );
2835   }
2836 
2837   set_java_calls(frc.get_java_call_count());
2838   set_inner_loops(frc.get_inner_loop_count());
2839 
2840   // No infinite loops, no reason to bail out.
2841   return false;
2842 }
2843 
2844 //-----------------------------too_many_traps----------------------------------
2845 // Report if there are too many traps at the current method and bci.
2846 // Return true if there was a trap, and/or PerMethodTrapLimit is exceeded.
2847 bool Compile::too_many_traps(ciMethod* method,
2848                              int bci,
2849                              Deoptimization::DeoptReason reason) {
2850   ciMethodData* md = method->method_data();
2851   if (md->is_empty()) {
2852     // Assume the trap has not occurred, or that it occurred only
2853     // because of a transient condition during start-up in the interpreter.
2854     return false;
2855   }
2856   if (md->has_trap_at(bci, reason) != 0) {
2857     // Assume PerBytecodeTrapLimit==0, for a more conservative heuristic.
2858     // Also, if there are multiple reasons, or if there is no per-BCI record,
2859     // assume the worst.
2860     if (log())
2861       log()->elem("observe trap='%s' count='%d'",
2862                   Deoptimization::trap_reason_name(reason),
2863                   md->trap_count(reason));
2864     return true;
2865   } else {
2866     // Ignore method/bci and see if there have been too many globally.
2867     return too_many_traps(reason, md);
2868   }
2869 }
2870 
2871 // Less-accurate variant which does not require a method and bci.
2872 bool Compile::too_many_traps(Deoptimization::DeoptReason reason,
2873                              ciMethodData* logmd) {
2874  if (trap_count(reason) >= (uint)PerMethodTrapLimit) {
2875     // Too many traps globally.
2876     // Note that we use cumulative trap_count, not just md->trap_count.
2877     if (log()) {
2878       int mcount = (logmd == NULL)? -1: (int)logmd->trap_count(reason);
2879       log()->elem("observe trap='%s' count='0' mcount='%d' ccount='%d'",
2880                   Deoptimization::trap_reason_name(reason),
2881                   mcount, trap_count(reason));
2882     }
2883     return true;
2884   } else {
2885     // The coast is clear.
2886     return false;
2887   }
2888 }
2889 
2890 //--------------------------too_many_recompiles--------------------------------
2891 // Report if there are too many recompiles at the current method and bci.
2892 // Consults PerBytecodeRecompilationCutoff and PerMethodRecompilationCutoff.
2893 // Is not eager to return true, since this will cause the compiler to use
2894 // Action_none for a trap point, to avoid too many recompilations.
2895 bool Compile::too_many_recompiles(ciMethod* method,
2896                                   int bci,
2897                                   Deoptimization::DeoptReason reason) {
2898   ciMethodData* md = method->method_data();
2899   if (md->is_empty()) {
2900     // Assume the trap has not occurred, or that it occurred only
2901     // because of a transient condition during start-up in the interpreter.
2902     return false;
2903   }
2904   // Pick a cutoff point well within PerBytecodeRecompilationCutoff.
2905   uint bc_cutoff = (uint) PerBytecodeRecompilationCutoff / 8;
2906   uint m_cutoff  = (uint) PerMethodRecompilationCutoff / 2 + 1;  // not zero
2907   Deoptimization::DeoptReason per_bc_reason
2908     = Deoptimization::reason_recorded_per_bytecode_if_any(reason);
2909   if ((per_bc_reason == Deoptimization::Reason_none
2910        || md->has_trap_at(bci, reason) != 0)
2911       // The trap frequency measure we care about is the recompile count:
2912       && md->trap_recompiled_at(bci)
2913       && md->overflow_recompile_count() >= bc_cutoff) {
2914     // Do not emit a trap here if it has already caused recompilations.
2915     // Also, if there are multiple reasons, or if there is no per-BCI record,
2916     // assume the worst.
2917     if (log())
2918       log()->elem("observe trap='%s recompiled' count='%d' recompiles2='%d'",
2919                   Deoptimization::trap_reason_name(reason),
2920                   md->trap_count(reason),
2921                   md->overflow_recompile_count());
2922     return true;
2923   } else if (trap_count(reason) != 0
2924              && decompile_count() >= m_cutoff) {
2925     // Too many recompiles globally, and we have seen this sort of trap.
2926     // Use cumulative decompile_count, not just md->decompile_count.
2927     if (log())
2928       log()->elem("observe trap='%s' count='%d' mcount='%d' decompiles='%d' mdecompiles='%d'",
2929                   Deoptimization::trap_reason_name(reason),
2930                   md->trap_count(reason), trap_count(reason),
2931                   md->decompile_count(), decompile_count());
2932     return true;
2933   } else {
2934     // The coast is clear.
2935     return false;
2936   }
2937 }
2938 
2939 
2940 #ifndef PRODUCT
2941 //------------------------------verify_graph_edges---------------------------
2942 // Walk the Graph and verify that there is a one-to-one correspondence
2943 // between Use-Def edges and Def-Use edges in the graph.
2944 void Compile::verify_graph_edges(bool no_dead_code) {
2945   if (VerifyGraphEdges) {
2946     ResourceArea *area = Thread::current()->resource_area();
2947     Unique_Node_List visited(area);
2948     // Call recursive graph walk to check edges
2949     _root->verify_edges(visited);
2950     if (no_dead_code) {
2951       // Now make sure that no visited node is used by an unvisited node.
2952       bool dead_nodes = 0;
2953       Unique_Node_List checked(area);
2954       while (visited.size() > 0) {
2955         Node* n = visited.pop();
2956         checked.push(n);
2957         for (uint i = 0; i < n->outcnt(); i++) {
2958           Node* use = n->raw_out(i);
2959           if (checked.member(use))  continue;  // already checked
2960           if (visited.member(use))  continue;  // already in the graph
2961           if (use->is_Con())        continue;  // a dead ConNode is OK
2962           // At this point, we have found a dead node which is DU-reachable.
2963           if (dead_nodes++ == 0)
2964             tty->print_cr("*** Dead nodes reachable via DU edges:");
2965           use->dump(2);
2966           tty->print_cr("---");
2967           checked.push(use);  // No repeats; pretend it is now checked.
2968         }
2969       }
2970       assert(dead_nodes == 0, "using nodes must be reachable from root");
2971     }
2972   }
2973 }
2974 #endif
2975 
2976 // The Compile object keeps track of failure reasons separately from the ciEnv.
2977 // This is required because there is not quite a 1-1 relation between the
2978 // ciEnv and its compilation task and the Compile object.  Note that one
2979 // ciEnv might use two Compile objects, if C2Compiler::compile_method decides
2980 // to backtrack and retry without subsuming loads.  Other than this backtracking
2981 // behavior, the Compile's failure reason is quietly copied up to the ciEnv
2982 // by the logic in C2Compiler.
2983 void Compile::record_failure(const char* reason) {
2984   if (log() != NULL) {
2985     log()->elem("failure reason='%s' phase='compile'", reason);
2986   }
2987   if (_failure_reason == NULL) {
2988     // Record the first failure reason.
2989     _failure_reason = reason;
2990   }
2991   if (!C->failure_reason_is(C2Compiler::retry_no_subsuming_loads())) {
2992     C->print_method(_failure_reason);
2993   }
2994   _root = NULL;  // flush the graph, too
2995 }
2996 
2997 Compile::TracePhase::TracePhase(const char* name, elapsedTimer* accumulator, bool dolog)
2998   : TraceTime(NULL, accumulator, false NOT_PRODUCT( || TimeCompiler ), false)
2999 {
3000   if (dolog) {
3001     C = Compile::current();
3002     _log = C->log();
3003   } else {
3004     C = NULL;
3005     _log = NULL;
3006   }
3007   if (_log != NULL) {
3008     _log->begin_head("phase name='%s' nodes='%d'", name, C->unique());
3009     _log->stamp();
3010     _log->end_head();
3011   }
3012 }
3013 
3014 Compile::TracePhase::~TracePhase() {
3015   if (_log != NULL) {
3016     _log->done("phase nodes='%d'", C->unique());
3017   }
3018 }
3019 
3020 //=============================================================================
3021 // Two Constant's are equal when the type and the value are equal.
3022 bool Compile::Constant::operator==(const Constant& other) {
3023   if (type()          != other.type()         )  return false;
3024   if (can_be_reused() != other.can_be_reused())  return false;
3025   // For floating point values we compare the bit pattern.
3026   switch (type()) {
3027   case T_FLOAT:   return (_value.i == other._value.i);
3028   case T_LONG:
3029   case T_DOUBLE:  return (_value.j == other._value.j);
3030   case T_OBJECT:
3031   case T_ADDRESS: return (_value.l == other._value.l);
3032   case T_VOID:    return (_value.l == other._value.l);  // jump-table entries
3033   default: ShouldNotReachHere();
3034   }
3035   return false;
3036 }
3037 
3038 // Emit constants grouped in the following order:
3039 static BasicType type_order[] = {
3040   T_FLOAT,    // 32-bit
3041   T_OBJECT,   // 32 or 64-bit
3042   T_ADDRESS,  // 32 or 64-bit
3043   T_DOUBLE,   // 64-bit
3044   T_LONG,     // 64-bit
3045   T_VOID,     // 32 or 64-bit (jump-tables are at the end of the constant table for code emission reasons)
3046   T_ILLEGAL
3047 };
3048 
3049 static int type_to_size_in_bytes(BasicType t) {
3050   switch (t) {
3051   case T_LONG:    return sizeof(jlong  );
3052   case T_FLOAT:   return sizeof(jfloat );
3053   case T_DOUBLE:  return sizeof(jdouble);
3054     // We use T_VOID as marker for jump-table entries (labels) which
3055     // need an interal word relocation.
3056   case T_VOID:
3057   case T_ADDRESS:
3058   case T_OBJECT:  return sizeof(jobject);
3059   }
3060 
3061   ShouldNotReachHere();
3062   return -1;
3063 }
3064 
3065 void Compile::ConstantTable::calculate_offsets_and_size() {
3066   int size = 0;
3067   for (int t = 0; type_order[t] != T_ILLEGAL; t++) {
3068     BasicType type = type_order[t];
3069 
3070     for (int i = 0; i < _constants.length(); i++) {
3071       Constant con = _constants.at(i);
3072       if (con.type() != type)  continue;  // Skip other types.
3073 
3074       // Align size for type.
3075       int typesize = type_to_size_in_bytes(con.type());
3076       size = align_size_up(size, typesize);
3077 
3078       // Set offset.
3079       con.set_offset(size);
3080       _constants.at_put(i, con);
3081 
3082       // Add type size.
3083       size = size + typesize;
3084     }
3085   }
3086 
3087   // Align size up to the next section start (which is insts; see
3088   // CodeBuffer::align_at_start).
3089   assert(_size == -1, "already set?");
3090   _size = align_size_up(size, CodeEntryAlignment);
3091 
3092   if (Matcher::constant_table_absolute_addressing) {
3093     set_table_base_offset(0);  // No table base offset required
3094   } else {
3095     if (UseRDPCForConstantTableBase) {
3096       // table base offset is set in MachConstantBaseNode::emit
3097     } else {
3098       // When RDPC is not used, the table base is set into the middle of
3099       // the constant table.
3100       int half_size = _size / 2;
3101       assert(half_size * 2 == _size, "sanity");
3102       set_table_base_offset(-half_size);
3103     }
3104   }
3105 }
3106 
3107 void Compile::ConstantTable::emit(CodeBuffer& cb) {
3108   MacroAssembler _masm(&cb);
3109   for (int t = 0; type_order[t] != T_ILLEGAL; t++) {
3110     BasicType type = type_order[t];
3111 
3112     for (int i = 0; i < _constants.length(); i++) {
3113       Constant con = _constants.at(i);
3114       if (con.type() != type)  continue;  // Skip other types.
3115 
3116       address constant_addr;
3117       switch (con.type()) {
3118       case T_LONG:   constant_addr = _masm.long_constant(  con.get_jlong()  ); break;
3119       case T_FLOAT:  constant_addr = _masm.float_constant( con.get_jfloat() ); break;
3120       case T_DOUBLE: constant_addr = _masm.double_constant(con.get_jdouble()); break;
3121       case T_OBJECT: {
3122         jobject obj = con.get_jobject();
3123         int oop_index = _masm.oop_recorder()->find_index(obj);
3124         constant_addr = _masm.address_constant((address) obj, oop_Relocation::spec(oop_index));
3125         break;
3126       }
3127       case T_ADDRESS: {
3128         address addr = (address) con.get_jobject();
3129         constant_addr = _masm.address_constant(addr);
3130         break;
3131       }
3132       // We use T_VOID as marker for jump-table entries (labels) which
3133       // need an interal word relocation.
3134       case T_VOID: {
3135         // Write a dummy word.  The real value is filled in later
3136         // in fill_jump_table_in_constant_table.
3137         address addr = (address) con.get_jobject();
3138         constant_addr = _masm.address_constant(addr);
3139         break;
3140       }
3141       default: ShouldNotReachHere();
3142       }
3143       assert(constant_addr != NULL, "consts section too small");
3144       assert((constant_addr - _masm.code()->consts()->start()) == con.offset(), err_msg("must be: %d == %d", constant_addr - _masm.code()->consts()->start(), con.offset()));
3145     }
3146   }
3147 }
3148 
3149 int Compile::ConstantTable::find_offset(Constant& con) const {
3150   int idx = _constants.find(con);
3151   assert(idx != -1, "constant must be in constant table");
3152   int offset = _constants.at(idx).offset();
3153   assert(offset != -1, "constant table not emitted yet?");
3154   return offset;
3155 }
3156 
3157 void Compile::ConstantTable::add(Constant& con) {
3158   if (con.can_be_reused()) {
3159     int idx = _constants.find(con);
3160     if (idx != -1 && _constants.at(idx).can_be_reused()) {
3161       return;
3162     }
3163   }
3164   (void) _constants.append(con);
3165 }
3166 
3167 Compile::Constant Compile::ConstantTable::add(BasicType type, jvalue value) {
3168   Constant con(type, value);
3169   add(con);
3170   return con;
3171 }
3172 
3173 Compile::Constant Compile::ConstantTable::add(MachOper* oper) {
3174   jvalue value;
3175   BasicType type = oper->type()->basic_type();
3176   switch (type) {
3177   case T_LONG:    value.j = oper->constantL(); break;
3178   case T_FLOAT:   value.f = oper->constantF(); break;
3179   case T_DOUBLE:  value.d = oper->constantD(); break;
3180   case T_OBJECT:
3181   case T_ADDRESS: value.l = (jobject) oper->constant(); break;
3182   default: ShouldNotReachHere();
3183   }
3184   return add(type, value);
3185 }
3186 
3187 Compile::Constant Compile::ConstantTable::allocate_jump_table(MachConstantNode* n) {
3188   jvalue value;
3189   // We can use the node pointer here to identify the right jump-table
3190   // as this method is called from Compile::Fill_buffer right before
3191   // the MachNodes are emitted and the jump-table is filled (means the
3192   // MachNode pointers do not change anymore).
3193   value.l = (jobject) n;
3194   Constant con(T_VOID, value, false);  // Labels of a jump-table cannot be reused.
3195   for (uint i = 0; i < n->outcnt(); i++) {
3196     add(con);
3197   }
3198   return con;
3199 }
3200 
3201 void Compile::ConstantTable::fill_jump_table(CodeBuffer& cb, MachConstantNode* n, GrowableArray<Label*> labels) const {
3202   // If called from Compile::scratch_emit_size do nothing.
3203   if (Compile::current()->in_scratch_emit_size())  return;
3204 
3205   assert(labels.is_nonempty(), "must be");
3206   assert((uint) labels.length() == n->outcnt(), err_msg("must be equal: %d == %d", labels.length(), n->outcnt()));
3207 
3208   // Since MachConstantNode::constant_offset() also contains
3209   // table_base_offset() we need to subtract the table_base_offset()
3210   // to get the plain offset into the constant table.
3211   int offset = n->constant_offset() - table_base_offset();
3212 
3213   MacroAssembler _masm(&cb);
3214   address* jump_table_base = (address*) (_masm.code()->consts()->start() + offset);
3215 
3216   for (int i = 0; i < labels.length(); i++) {
3217     address* constant_addr = &jump_table_base[i];
3218     assert(*constant_addr == (address) n, "all jump-table entries must contain node pointer");
3219     *constant_addr = cb.consts()->target(*labels.at(i), (address) constant_addr);
3220     cb.consts()->relocate((address) constant_addr, relocInfo::internal_word_type);
3221   }
3222 }