rev 3898 : 8005031: Some cleanup in c2 to prepare for incremental inlining support
Summary: collection of small changes to prepare for incremental inlining.
Reviewed-by:

   1 /*
   2  * Copyright (c) 1997, 2012, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "asm/macroAssembler.hpp"
  27 #include "asm/macroAssembler.inline.hpp"
  28 #include "classfile/systemDictionary.hpp"
  29 #include "code/exceptionHandlerTable.hpp"
  30 #include "code/nmethod.hpp"
  31 #include "compiler/compileLog.hpp"
  32 #include "compiler/disassembler.hpp"
  33 #include "compiler/oopMap.hpp"
  34 #include "opto/addnode.hpp"
  35 #include "opto/block.hpp"
  36 #include "opto/c2compiler.hpp"
  37 #include "opto/callGenerator.hpp"
  38 #include "opto/callnode.hpp"
  39 #include "opto/cfgnode.hpp"
  40 #include "opto/chaitin.hpp"
  41 #include "opto/compile.hpp"
  42 #include "opto/connode.hpp"
  43 #include "opto/divnode.hpp"
  44 #include "opto/escape.hpp"
  45 #include "opto/idealGraphPrinter.hpp"
  46 #include "opto/loopnode.hpp"
  47 #include "opto/machnode.hpp"
  48 #include "opto/macro.hpp"
  49 #include "opto/matcher.hpp"
  50 #include "opto/memnode.hpp"
  51 #include "opto/mulnode.hpp"
  52 #include "opto/node.hpp"
  53 #include "opto/opcodes.hpp"
  54 #include "opto/output.hpp"
  55 #include "opto/parse.hpp"
  56 #include "opto/phaseX.hpp"
  57 #include "opto/rootnode.hpp"
  58 #include "opto/runtime.hpp"
  59 #include "opto/stringopts.hpp"
  60 #include "opto/type.hpp"
  61 #include "opto/vectornode.hpp"
  62 #include "runtime/arguments.hpp"
  63 #include "runtime/signature.hpp"
  64 #include "runtime/stubRoutines.hpp"
  65 #include "runtime/timer.hpp"
  66 #include "utilities/copy.hpp"
  67 #ifdef TARGET_ARCH_MODEL_x86_32
  68 # include "adfiles/ad_x86_32.hpp"
  69 #endif
  70 #ifdef TARGET_ARCH_MODEL_x86_64
  71 # include "adfiles/ad_x86_64.hpp"
  72 #endif
  73 #ifdef TARGET_ARCH_MODEL_sparc
  74 # include "adfiles/ad_sparc.hpp"
  75 #endif
  76 #ifdef TARGET_ARCH_MODEL_zero
  77 # include "adfiles/ad_zero.hpp"
  78 #endif
  79 #ifdef TARGET_ARCH_MODEL_arm
  80 # include "adfiles/ad_arm.hpp"
  81 #endif
  82 #ifdef TARGET_ARCH_MODEL_ppc
  83 # include "adfiles/ad_ppc.hpp"
  84 #endif
  85 
  86 
  87 // -------------------- Compile::mach_constant_base_node -----------------------
  88 // Constant table base node singleton.
  89 MachConstantBaseNode* Compile::mach_constant_base_node() {
  90   if (_mach_constant_base_node == NULL) {
  91     _mach_constant_base_node = new (C) MachConstantBaseNode();
  92     _mach_constant_base_node->add_req(C->root());
  93   }
  94   return _mach_constant_base_node;
  95 }
  96 
  97 
  98 /// Support for intrinsics.
  99 
 100 // Return the index at which m must be inserted (or already exists).
 101 // The sort order is by the address of the ciMethod, with is_virtual as minor key.
 102 int Compile::intrinsic_insertion_index(ciMethod* m, bool is_virtual) {
 103 #ifdef ASSERT
 104   for (int i = 1; i < _intrinsics->length(); i++) {
 105     CallGenerator* cg1 = _intrinsics->at(i-1);
 106     CallGenerator* cg2 = _intrinsics->at(i);
 107     assert(cg1->method() != cg2->method()
 108            ? cg1->method()     < cg2->method()
 109            : cg1->is_virtual() < cg2->is_virtual(),
 110            "compiler intrinsics list must stay sorted");
 111   }
 112 #endif
 113   // Binary search sorted list, in decreasing intervals [lo, hi].
 114   int lo = 0, hi = _intrinsics->length()-1;
 115   while (lo <= hi) {
 116     int mid = (uint)(hi + lo) / 2;
 117     ciMethod* mid_m = _intrinsics->at(mid)->method();
 118     if (m < mid_m) {
 119       hi = mid-1;
 120     } else if (m > mid_m) {
 121       lo = mid+1;
 122     } else {
 123       // look at minor sort key
 124       bool mid_virt = _intrinsics->at(mid)->is_virtual();
 125       if (is_virtual < mid_virt) {
 126         hi = mid-1;
 127       } else if (is_virtual > mid_virt) {
 128         lo = mid+1;
 129       } else {
 130         return mid;  // exact match
 131       }
 132     }
 133   }
 134   return lo;  // inexact match
 135 }
 136 
 137 void Compile::register_intrinsic(CallGenerator* cg) {
 138   if (_intrinsics == NULL) {
 139     _intrinsics = new GrowableArray<CallGenerator*>(60);
 140   }
 141   // This code is stolen from ciObjectFactory::insert.
 142   // Really, GrowableArray should have methods for
 143   // insert_at, remove_at, and binary_search.
 144   int len = _intrinsics->length();
 145   int index = intrinsic_insertion_index(cg->method(), cg->is_virtual());
 146   if (index == len) {
 147     _intrinsics->append(cg);
 148   } else {
 149 #ifdef ASSERT
 150     CallGenerator* oldcg = _intrinsics->at(index);
 151     assert(oldcg->method() != cg->method() || oldcg->is_virtual() != cg->is_virtual(), "don't register twice");
 152 #endif
 153     _intrinsics->append(_intrinsics->at(len-1));
 154     int pos;
 155     for (pos = len-2; pos >= index; pos--) {
 156       _intrinsics->at_put(pos+1,_intrinsics->at(pos));
 157     }
 158     _intrinsics->at_put(index, cg);
 159   }
 160   assert(find_intrinsic(cg->method(), cg->is_virtual()) == cg, "registration worked");
 161 }
 162 
 163 CallGenerator* Compile::find_intrinsic(ciMethod* m, bool is_virtual) {
 164   assert(m->is_loaded(), "don't try this on unloaded methods");
 165   if (_intrinsics != NULL) {
 166     int index = intrinsic_insertion_index(m, is_virtual);
 167     if (index < _intrinsics->length()
 168         && _intrinsics->at(index)->method() == m
 169         && _intrinsics->at(index)->is_virtual() == is_virtual) {
 170       return _intrinsics->at(index);
 171     }
 172   }
 173   // Lazily create intrinsics for intrinsic IDs well-known in the runtime.
 174   if (m->intrinsic_id() != vmIntrinsics::_none &&
 175       m->intrinsic_id() <= vmIntrinsics::LAST_COMPILER_INLINE) {
 176     CallGenerator* cg = make_vm_intrinsic(m, is_virtual);
 177     if (cg != NULL) {
 178       // Save it for next time:
 179       register_intrinsic(cg);
 180       return cg;
 181     } else {
 182       gather_intrinsic_statistics(m->intrinsic_id(), is_virtual, _intrinsic_disabled);
 183     }
 184   }
 185   return NULL;
 186 }
 187 
 188 // Compile:: register_library_intrinsics and make_vm_intrinsic are defined
 189 // in library_call.cpp.
 190 
 191 
 192 #ifndef PRODUCT
 193 // statistics gathering...
 194 
 195 juint  Compile::_intrinsic_hist_count[vmIntrinsics::ID_LIMIT] = {0};
 196 jubyte Compile::_intrinsic_hist_flags[vmIntrinsics::ID_LIMIT] = {0};
 197 
 198 bool Compile::gather_intrinsic_statistics(vmIntrinsics::ID id, bool is_virtual, int flags) {
 199   assert(id > vmIntrinsics::_none && id < vmIntrinsics::ID_LIMIT, "oob");
 200   int oflags = _intrinsic_hist_flags[id];
 201   assert(flags != 0, "what happened?");
 202   if (is_virtual) {
 203     flags |= _intrinsic_virtual;
 204   }
 205   bool changed = (flags != oflags);
 206   if ((flags & _intrinsic_worked) != 0) {
 207     juint count = (_intrinsic_hist_count[id] += 1);
 208     if (count == 1) {
 209       changed = true;           // first time
 210     }
 211     // increment the overall count also:
 212     _intrinsic_hist_count[vmIntrinsics::_none] += 1;
 213   }
 214   if (changed) {
 215     if (((oflags ^ flags) & _intrinsic_virtual) != 0) {
 216       // Something changed about the intrinsic's virtuality.
 217       if ((flags & _intrinsic_virtual) != 0) {
 218         // This is the first use of this intrinsic as a virtual call.
 219         if (oflags != 0) {
 220           // We already saw it as a non-virtual, so note both cases.
 221           flags |= _intrinsic_both;
 222         }
 223       } else if ((oflags & _intrinsic_both) == 0) {
 224         // This is the first use of this intrinsic as a non-virtual
 225         flags |= _intrinsic_both;
 226       }
 227     }
 228     _intrinsic_hist_flags[id] = (jubyte) (oflags | flags);
 229   }
 230   // update the overall flags also:
 231   _intrinsic_hist_flags[vmIntrinsics::_none] |= (jubyte) flags;
 232   return changed;
 233 }
 234 
 235 static char* format_flags(int flags, char* buf) {
 236   buf[0] = 0;
 237   if ((flags & Compile::_intrinsic_worked) != 0)    strcat(buf, ",worked");
 238   if ((flags & Compile::_intrinsic_failed) != 0)    strcat(buf, ",failed");
 239   if ((flags & Compile::_intrinsic_disabled) != 0)  strcat(buf, ",disabled");
 240   if ((flags & Compile::_intrinsic_virtual) != 0)   strcat(buf, ",virtual");
 241   if ((flags & Compile::_intrinsic_both) != 0)      strcat(buf, ",nonvirtual");
 242   if (buf[0] == 0)  strcat(buf, ",");
 243   assert(buf[0] == ',', "must be");
 244   return &buf[1];
 245 }
 246 
 247 void Compile::print_intrinsic_statistics() {
 248   char flagsbuf[100];
 249   ttyLocker ttyl;
 250   if (xtty != NULL)  xtty->head("statistics type='intrinsic'");
 251   tty->print_cr("Compiler intrinsic usage:");
 252   juint total = _intrinsic_hist_count[vmIntrinsics::_none];
 253   if (total == 0)  total = 1;  // avoid div0 in case of no successes
 254   #define PRINT_STAT_LINE(name, c, f) \
 255     tty->print_cr("  %4d (%4.1f%%) %s (%s)", (int)(c), ((c) * 100.0) / total, name, f);
 256   for (int index = 1 + (int)vmIntrinsics::_none; index < (int)vmIntrinsics::ID_LIMIT; index++) {
 257     vmIntrinsics::ID id = (vmIntrinsics::ID) index;
 258     int   flags = _intrinsic_hist_flags[id];
 259     juint count = _intrinsic_hist_count[id];
 260     if ((flags | count) != 0) {
 261       PRINT_STAT_LINE(vmIntrinsics::name_at(id), count, format_flags(flags, flagsbuf));
 262     }
 263   }
 264   PRINT_STAT_LINE("total", total, format_flags(_intrinsic_hist_flags[vmIntrinsics::_none], flagsbuf));
 265   if (xtty != NULL)  xtty->tail("statistics");
 266 }
 267 
 268 void Compile::print_statistics() {
 269   { ttyLocker ttyl;
 270     if (xtty != NULL)  xtty->head("statistics type='opto'");
 271     Parse::print_statistics();
 272     PhaseCCP::print_statistics();
 273     PhaseRegAlloc::print_statistics();
 274     Scheduling::print_statistics();
 275     PhasePeephole::print_statistics();
 276     PhaseIdealLoop::print_statistics();
 277     if (xtty != NULL)  xtty->tail("statistics");
 278   }
 279   if (_intrinsic_hist_flags[vmIntrinsics::_none] != 0) {
 280     // put this under its own <statistics> element.
 281     print_intrinsic_statistics();
 282   }
 283 }
 284 #endif //PRODUCT
 285 
 286 // Support for bundling info
 287 Bundle* Compile::node_bundling(const Node *n) {
 288   assert(valid_bundle_info(n), "oob");
 289   return &_node_bundling_base[n->_idx];
 290 }
 291 
 292 bool Compile::valid_bundle_info(const Node *n) {
 293   return (_node_bundling_limit > n->_idx);
 294 }
 295 
 296 
 297 void Compile::gvn_replace_by(Node* n, Node* nn) {
 298   for (DUIterator_Last imin, i = n->last_outs(imin); i >= imin; ) {
 299     Node* use = n->last_out(i);
 300     bool is_in_table = initial_gvn()->hash_delete(use);
 301     uint uses_found = 0;
 302     for (uint j = 0; j < use->len(); j++) {
 303       if (use->in(j) == n) {
 304         if (j < use->req())
 305           use->set_req(j, nn);
 306         else
 307           use->set_prec(j, nn);
 308         uses_found++;
 309       }
 310     }
 311     if (is_in_table) {
 312       // reinsert into table
 313       initial_gvn()->hash_find_insert(use);
 314     }
 315     record_for_igvn(use);
 316     i -= uses_found;    // we deleted 1 or more copies of this edge
 317   }
 318 }
 319 
 320 
 321 static inline bool not_a_node(const Node* n) {
 322   if (n == NULL)                   return true;
 323   if (((intptr_t)n & 1) != 0)      return true;  // uninitialized, etc.
 324   if (*(address*)n == badAddress)  return true;  // kill by Node::destruct
 325   return false;
 326 }
 327 
 328 // Identify all nodes that are reachable from below, useful.
 329 // Use breadth-first pass that records state in a Unique_Node_List,
 330 // recursive traversal is slower.
 331 void Compile::identify_useful_nodes(Unique_Node_List &useful) {
 332   int estimated_worklist_size = unique();
 333   useful.map( estimated_worklist_size, NULL );  // preallocate space
 334 
 335   // Initialize worklist
 336   if (root() != NULL)     { useful.push(root()); }
 337   // If 'top' is cached, declare it useful to preserve cached node
 338   if( cached_top_node() ) { useful.push(cached_top_node()); }
 339 
 340   // Push all useful nodes onto the list, breadthfirst
 341   for( uint next = 0; next < useful.size(); ++next ) {
 342     assert( next < unique(), "Unique useful nodes < total nodes");
 343     Node *n  = useful.at(next);
 344     uint max = n->len();
 345     for( uint i = 0; i < max; ++i ) {
 346       Node *m = n->in(i);
 347       if (not_a_node(m))  continue;
 348       useful.push(m);
 349     }
 350   }
 351 }
 352 
 353 // Update dead_node_list with any missing dead nodes using useful
 354 // list. Consider all non-useful nodes to be useless i.e., dead nodes.
 355 void Compile::update_dead_node_list(Unique_Node_List &useful) {
 356   uint max_idx = unique();
 357   VectorSet& useful_node_set = useful.member_set();
 358 
 359   for (uint node_idx = 0; node_idx < max_idx; node_idx++) {
 360     // If node with index node_idx is not in useful set,
 361     // mark it as dead in dead node list.
 362     if (! useful_node_set.test(node_idx) ) {
 363       record_dead_node(node_idx);
 364     }
 365   }
 366 }
 367 
 368 // Disconnect all useless nodes by disconnecting those at the boundary.
 369 void Compile::remove_useless_nodes(Unique_Node_List &useful) {
 370   uint next = 0;
 371   while (next < useful.size()) {
 372     Node *n = useful.at(next++);
 373     // Use raw traversal of out edges since this code removes out edges
 374     int max = n->outcnt();
 375     for (int j = 0; j < max; ++j) {
 376       Node* child = n->raw_out(j);
 377       if (! useful.member(child)) {
 378         assert(!child->is_top() || child != top(),
 379                "If top is cached in Compile object it is in useful list");
 380         // Only need to remove this out-edge to the useless node
 381         n->raw_del_out(j);
 382         --j;
 383         --max;
 384       }
 385     }
 386     if (n->outcnt() == 1 && n->has_special_unique_user()) {
 387       record_for_igvn(n->unique_out());
 388     }
 389   }
 390   // Remove useless macro and predicate opaq nodes
 391   for (int i = C->macro_count()-1; i >= 0; i--) {
 392     Node* n = C->macro_node(i);
 393     if (!useful.member(n)) {
 394       remove_macro_node(n);
 395     }
 396   }
 397   debug_only(verify_graph_edges(true/*check for no_dead_code*/);)
 398 }
 399 
 400 //------------------------------frame_size_in_words-----------------------------
 401 // frame_slots in units of words
 402 int Compile::frame_size_in_words() const {
 403   // shift is 0 in LP32 and 1 in LP64
 404   const int shift = (LogBytesPerWord - LogBytesPerInt);
 405   int words = _frame_slots >> shift;
 406   assert( words << shift == _frame_slots, "frame size must be properly aligned in LP64" );
 407   return words;
 408 }
 409 
 410 // ============================================================================
 411 //------------------------------CompileWrapper---------------------------------
 412 class CompileWrapper : public StackObj {
 413   Compile *const _compile;
 414  public:
 415   CompileWrapper(Compile* compile);
 416 
 417   ~CompileWrapper();
 418 };
 419 
 420 CompileWrapper::CompileWrapper(Compile* compile) : _compile(compile) {
 421   // the Compile* pointer is stored in the current ciEnv:
 422   ciEnv* env = compile->env();
 423   assert(env == ciEnv::current(), "must already be a ciEnv active");
 424   assert(env->compiler_data() == NULL, "compile already active?");
 425   env->set_compiler_data(compile);
 426   assert(compile == Compile::current(), "sanity");
 427 
 428   compile->set_type_dict(NULL);
 429   compile->set_type_hwm(NULL);
 430   compile->set_type_last_size(0);
 431   compile->set_last_tf(NULL, NULL);
 432   compile->set_indexSet_arena(NULL);
 433   compile->set_indexSet_free_block_list(NULL);
 434   compile->init_type_arena();
 435   Type::Initialize(compile);
 436   _compile->set_scratch_buffer_blob(NULL);
 437   _compile->begin_method();
 438 }
 439 CompileWrapper::~CompileWrapper() {
 440   _compile->end_method();
 441   if (_compile->scratch_buffer_blob() != NULL)
 442     BufferBlob::free(_compile->scratch_buffer_blob());
 443   _compile->env()->set_compiler_data(NULL);
 444 }
 445 
 446 
 447 //----------------------------print_compile_messages---------------------------
 448 void Compile::print_compile_messages() {
 449 #ifndef PRODUCT
 450   // Check if recompiling
 451   if (_subsume_loads == false && PrintOpto) {
 452     // Recompiling without allowing machine instructions to subsume loads
 453     tty->print_cr("*********************************************************");
 454     tty->print_cr("** Bailout: Recompile without subsuming loads          **");
 455     tty->print_cr("*********************************************************");
 456   }
 457   if (_do_escape_analysis != DoEscapeAnalysis && PrintOpto) {
 458     // Recompiling without escape analysis
 459     tty->print_cr("*********************************************************");
 460     tty->print_cr("** Bailout: Recompile without escape analysis          **");
 461     tty->print_cr("*********************************************************");
 462   }
 463   if (env()->break_at_compile()) {
 464     // Open the debugger when compiling this method.
 465     tty->print("### Breaking when compiling: ");
 466     method()->print_short_name();
 467     tty->cr();
 468     BREAKPOINT;
 469   }
 470 
 471   if( PrintOpto ) {
 472     if (is_osr_compilation()) {
 473       tty->print("[OSR]%3d", _compile_id);
 474     } else {
 475       tty->print("%3d", _compile_id);
 476     }
 477   }
 478 #endif
 479 }
 480 
 481 
 482 //-----------------------init_scratch_buffer_blob------------------------------
 483 // Construct a temporary BufferBlob and cache it for this compile.
 484 void Compile::init_scratch_buffer_blob(int const_size) {
 485   // If there is already a scratch buffer blob allocated and the
 486   // constant section is big enough, use it.  Otherwise free the
 487   // current and allocate a new one.
 488   BufferBlob* blob = scratch_buffer_blob();
 489   if ((blob != NULL) && (const_size <= _scratch_const_size)) {
 490     // Use the current blob.
 491   } else {
 492     if (blob != NULL) {
 493       BufferBlob::free(blob);
 494     }
 495 
 496     ResourceMark rm;
 497     _scratch_const_size = const_size;
 498     int size = (MAX_inst_size + MAX_stubs_size + _scratch_const_size);
 499     blob = BufferBlob::create("Compile::scratch_buffer", size);
 500     // Record the buffer blob for next time.
 501     set_scratch_buffer_blob(blob);
 502     // Have we run out of code space?
 503     if (scratch_buffer_blob() == NULL) {
 504       // Let CompilerBroker disable further compilations.
 505       record_failure("Not enough space for scratch buffer in CodeCache");
 506       return;
 507     }
 508   }
 509 
 510   // Initialize the relocation buffers
 511   relocInfo* locs_buf = (relocInfo*) blob->content_end() - MAX_locs_size;
 512   set_scratch_locs_memory(locs_buf);
 513 }
 514 
 515 
 516 //-----------------------scratch_emit_size-------------------------------------
 517 // Helper function that computes size by emitting code
 518 uint Compile::scratch_emit_size(const Node* n) {
 519   // Start scratch_emit_size section.
 520   set_in_scratch_emit_size(true);
 521 
 522   // Emit into a trash buffer and count bytes emitted.
 523   // This is a pretty expensive way to compute a size,
 524   // but it works well enough if seldom used.
 525   // All common fixed-size instructions are given a size
 526   // method by the AD file.
 527   // Note that the scratch buffer blob and locs memory are
 528   // allocated at the beginning of the compile task, and
 529   // may be shared by several calls to scratch_emit_size.
 530   // The allocation of the scratch buffer blob is particularly
 531   // expensive, since it has to grab the code cache lock.
 532   BufferBlob* blob = this->scratch_buffer_blob();
 533   assert(blob != NULL, "Initialize BufferBlob at start");
 534   assert(blob->size() > MAX_inst_size, "sanity");
 535   relocInfo* locs_buf = scratch_locs_memory();
 536   address blob_begin = blob->content_begin();
 537   address blob_end   = (address)locs_buf;
 538   assert(blob->content_contains(blob_end), "sanity");
 539   CodeBuffer buf(blob_begin, blob_end - blob_begin);
 540   buf.initialize_consts_size(_scratch_const_size);
 541   buf.initialize_stubs_size(MAX_stubs_size);
 542   assert(locs_buf != NULL, "sanity");
 543   int lsize = MAX_locs_size / 3;
 544   buf.consts()->initialize_shared_locs(&locs_buf[lsize * 0], lsize);
 545   buf.insts()->initialize_shared_locs( &locs_buf[lsize * 1], lsize);
 546   buf.stubs()->initialize_shared_locs( &locs_buf[lsize * 2], lsize);
 547 
 548   // Do the emission.
 549 
 550   Label fakeL; // Fake label for branch instructions.
 551   Label*   saveL = NULL;
 552   uint save_bnum = 0;
 553   bool is_branch = n->is_MachBranch();
 554   if (is_branch) {
 555     MacroAssembler masm(&buf);
 556     masm.bind(fakeL);
 557     n->as_MachBranch()->save_label(&saveL, &save_bnum);
 558     n->as_MachBranch()->label_set(&fakeL, 0);
 559   }
 560   n->emit(buf, this->regalloc());
 561   if (is_branch) // Restore label.
 562     n->as_MachBranch()->label_set(saveL, save_bnum);
 563 
 564   // End scratch_emit_size section.
 565   set_in_scratch_emit_size(false);
 566 
 567   return buf.insts_size();
 568 }
 569 
 570 
 571 // ============================================================================
 572 //------------------------------Compile standard-------------------------------
 573 debug_only( int Compile::_debug_idx = 100000; )
 574 
 575 // Compile a method.  entry_bci is -1 for normal compilations and indicates
 576 // the continuation bci for on stack replacement.
 577 
 578 
 579 Compile::Compile( ciEnv* ci_env, C2Compiler* compiler, ciMethod* target, int osr_bci, bool subsume_loads, bool do_escape_analysis )
 580                 : Phase(Compiler),
 581                   _env(ci_env),
 582                   _log(ci_env->log()),
 583                   _compile_id(ci_env->compile_id()),
 584                   _save_argument_registers(false),
 585                   _stub_name(NULL),
 586                   _stub_function(NULL),
 587                   _stub_entry_point(NULL),
 588                   _method(target),
 589                   _entry_bci(osr_bci),
 590                   _initial_gvn(NULL),
 591                   _for_igvn(NULL),
 592                   _warm_calls(NULL),
 593                   _subsume_loads(subsume_loads),
 594                   _do_escape_analysis(do_escape_analysis),
 595                   _failure_reason(NULL),
 596                   _code_buffer("Compile::Fill_buffer"),
 597                   _orig_pc_slot(0),
 598                   _orig_pc_slot_offset_in_bytes(0),
 599                   _has_method_handle_invokes(false),
 600                   _mach_constant_base_node(NULL),
 601                   _node_bundling_limit(0),
 602                   _node_bundling_base(NULL),
 603                   _java_calls(0),
 604                   _inner_loops(0),
 605                   _scratch_const_size(-1),
 606                   _in_scratch_emit_size(false),
 607                   _dead_node_list(comp_arena()),
 608                   _dead_node_count(0),
 609 #ifndef PRODUCT
 610                   _trace_opto_output(TraceOptoOutput || method()->has_option("TraceOptoOutput")),
 611                   _printer(IdealGraphPrinter::printer()),
 612 #endif
 613                   _congraph(NULL),
 614                   _print_inlining_list(NULL),
 615                   _print_inlining(0) {
 616   C = this;
 617 
 618   CompileWrapper cw(this);
 619 #ifndef PRODUCT
 620   if (TimeCompiler2) {
 621     tty->print(" ");
 622     target->holder()->name()->print();
 623     tty->print(".");
 624     target->print_short_name();
 625     tty->print("  ");
 626   }
 627   TraceTime t1("Total compilation time", &_t_totalCompilation, TimeCompiler, TimeCompiler2);
 628   TraceTime t2(NULL, &_t_methodCompilation, TimeCompiler, false);
 629   bool print_opto_assembly = PrintOptoAssembly || _method->has_option("PrintOptoAssembly");
 630   if (!print_opto_assembly) {
 631     bool print_assembly = (PrintAssembly || _method->should_print_assembly());
 632     if (print_assembly && !Disassembler::can_decode()) {
 633       tty->print_cr("PrintAssembly request changed to PrintOptoAssembly");
 634       print_opto_assembly = true;
 635     }
 636   }
 637   set_print_assembly(print_opto_assembly);
 638   set_parsed_irreducible_loop(false);
 639 #endif
 640 
 641   if (ProfileTraps) {
 642     // Make sure the method being compiled gets its own MDO,
 643     // so we can at least track the decompile_count().
 644     method()->ensure_method_data();
 645   }
 646 
 647   Init(::AliasLevel);
 648 
 649 
 650   print_compile_messages();
 651 
 652   if (UseOldInlining || PrintCompilation NOT_PRODUCT( || PrintOpto) )
 653     _ilt = InlineTree::build_inline_tree_root();
 654   else
 655     _ilt = NULL;
 656 
 657   // Even if NO memory addresses are used, MergeMem nodes must have at least 1 slice
 658   assert(num_alias_types() >= AliasIdxRaw, "");
 659 
 660 #define MINIMUM_NODE_HASH  1023
 661   // Node list that Iterative GVN will start with
 662   Unique_Node_List for_igvn(comp_arena());
 663   set_for_igvn(&for_igvn);
 664 
 665   // GVN that will be run immediately on new nodes
 666   uint estimated_size = method()->code_size()*4+64;
 667   estimated_size = (estimated_size < MINIMUM_NODE_HASH ? MINIMUM_NODE_HASH : estimated_size);
 668   PhaseGVN gvn(node_arena(), estimated_size);
 669   set_initial_gvn(&gvn);
 670 
 671   if (PrintInlining) {
 672     _print_inlining_list = new (comp_arena())GrowableArray<PrintInliningEvent>(comp_arena(), 1, 1, PrintInliningEvent());
 673   }
 674   { // Scope for timing the parser
 675     TracePhase t3("parse", &_t_parser, true);
 676 
 677     // Put top into the hash table ASAP.
 678     initial_gvn()->transform_no_reclaim(top());
 679 
 680     // Set up tf(), start(), and find a CallGenerator.
 681     CallGenerator* cg = NULL;
 682     if (is_osr_compilation()) {
 683       const TypeTuple *domain = StartOSRNode::osr_domain();
 684       const TypeTuple *range = TypeTuple::make_range(method()->signature());
 685       init_tf(TypeFunc::make(domain, range));
 686       StartNode* s = new (this) StartOSRNode(root(), domain);
 687       initial_gvn()->set_type_bottom(s);
 688       init_start(s);
 689       cg = CallGenerator::for_osr(method(), entry_bci());
 690     } else {
 691       // Normal case.
 692       init_tf(TypeFunc::make(method()));
 693       StartNode* s = new (this) StartNode(root(), tf()->domain());
 694       initial_gvn()->set_type_bottom(s);
 695       init_start(s);
 696       if (method()->intrinsic_id() == vmIntrinsics::_Reference_get && UseG1GC) {
 697         // With java.lang.ref.reference.get() we must go through the
 698         // intrinsic when G1 is enabled - even when get() is the root
 699         // method of the compile - so that, if necessary, the value in
 700         // the referent field of the reference object gets recorded by
 701         // the pre-barrier code.
 702         // Specifically, if G1 is enabled, the value in the referent
 703         // field is recorded by the G1 SATB pre barrier. This will
 704         // result in the referent being marked live and the reference
 705         // object removed from the list of discovered references during
 706         // reference processing.
 707         cg = find_intrinsic(method(), false);
 708       }
 709       if (cg == NULL) {
 710         float past_uses = method()->interpreter_invocation_count();
 711         float expected_uses = past_uses;
 712         cg = CallGenerator::for_inline(method(), expected_uses);
 713       }
 714     }
 715     if (failing())  return;
 716     if (cg == NULL) {
 717       record_method_not_compilable_all_tiers("cannot parse method");
 718       return;
 719     }
 720     JVMState* jvms = build_start_state(start(), tf());
 721     if ((jvms = cg->generate(jvms)) == NULL) {
 722       record_method_not_compilable("method parse failed");
 723       return;
 724     }
 725     GraphKit kit(jvms);
 726 
 727     if (!kit.stopped()) {
 728       // Accept return values, and transfer control we know not where.
 729       // This is done by a special, unique ReturnNode bound to root.
 730       return_values(kit.jvms());
 731     }
 732 
 733     if (kit.has_exceptions()) {
 734       // Any exceptions that escape from this call must be rethrown
 735       // to whatever caller is dynamically above us on the stack.
 736       // This is done by a special, unique RethrowNode bound to root.
 737       rethrow_exceptions(kit.transfer_exceptions_into_jvms());
 738     }
 739 
 740     if (!failing() && has_stringbuilder()) {
 741       {
 742         // remove useless nodes to make the usage analysis simpler
 743         ResourceMark rm;
 744         PhaseRemoveUseless pru(initial_gvn(), &for_igvn);
 745       }
 746 
 747       {
 748         ResourceMark rm;
 749         print_method("Before StringOpts", 3);
 750         PhaseStringOpts pso(initial_gvn(), &for_igvn);
 751         print_method("After StringOpts", 3);
 752       }
 753 
 754       // now inline anything that we skipped the first time around
 755       while (_late_inlines.length() > 0) {
 756         CallGenerator* cg = _late_inlines.pop();
 757         cg->do_late_inline();
 758         if (failing())  return;
 759       }
 760     }
 761     assert(_late_inlines.length() == 0, "should have been processed");
 762     dump_inlining();
 763 
 764     print_method("Before RemoveUseless", 3);
 765 
 766     // Remove clutter produced by parsing.
 767     if (!failing()) {
 768       ResourceMark rm;
 769       PhaseRemoveUseless pru(initial_gvn(), &for_igvn);
 770     }
 771   }
 772 
 773   // Note:  Large methods are capped off in do_one_bytecode().
 774   if (failing())  return;
 775 
 776   // After parsing, node notes are no longer automagic.
 777   // They must be propagated by register_new_node_with_optimizer(),
 778   // clone(), or the like.
 779   set_default_node_notes(NULL);
 780 
 781   for (;;) {
 782     int successes = Inline_Warm();
 783     if (failing())  return;
 784     if (successes == 0)  break;
 785   }
 786 
 787   // Drain the list.
 788   Finish_Warm();
 789 #ifndef PRODUCT
 790   if (_printer) {
 791     _printer->print_inlining(this);
 792   }
 793 #endif
 794 
 795   if (failing())  return;
 796   NOT_PRODUCT( verify_graph_edges(); )
 797 
 798   // Now optimize
 799   Optimize();
 800   if (failing())  return;
 801   NOT_PRODUCT( verify_graph_edges(); )
 802 
 803 #ifndef PRODUCT
 804   if (PrintIdeal) {
 805     ttyLocker ttyl;  // keep the following output all in one block
 806     // This output goes directly to the tty, not the compiler log.
 807     // To enable tools to match it up with the compilation activity,
 808     // be sure to tag this tty output with the compile ID.
 809     if (xtty != NULL) {
 810       xtty->head("ideal compile_id='%d'%s", compile_id(),
 811                  is_osr_compilation()    ? " compile_kind='osr'" :
 812                  "");
 813     }
 814     root()->dump(9999);
 815     if (xtty != NULL) {
 816       xtty->tail("ideal");
 817     }
 818   }
 819 #endif
 820 
 821   // Now that we know the size of all the monitors we can add a fixed slot
 822   // for the original deopt pc.
 823 
 824   _orig_pc_slot =  fixed_slots();
 825   int next_slot = _orig_pc_slot + (sizeof(address) / VMRegImpl::stack_slot_size);
 826   set_fixed_slots(next_slot);
 827 
 828   // Now generate code
 829   Code_Gen();
 830   if (failing())  return;
 831 
 832   // Check if we want to skip execution of all compiled code.
 833   {
 834 #ifndef PRODUCT
 835     if (OptoNoExecute) {
 836       record_method_not_compilable("+OptoNoExecute");  // Flag as failed
 837       return;
 838     }
 839     TracePhase t2("install_code", &_t_registerMethod, TimeCompiler);
 840 #endif
 841 
 842     if (is_osr_compilation()) {
 843       _code_offsets.set_value(CodeOffsets::Verified_Entry, 0);
 844       _code_offsets.set_value(CodeOffsets::OSR_Entry, _first_block_size);
 845     } else {
 846       _code_offsets.set_value(CodeOffsets::Verified_Entry, _first_block_size);
 847       _code_offsets.set_value(CodeOffsets::OSR_Entry, 0);
 848     }
 849 
 850     env()->register_method(_method, _entry_bci,
 851                            &_code_offsets,
 852                            _orig_pc_slot_offset_in_bytes,
 853                            code_buffer(),
 854                            frame_size_in_words(), _oop_map_set,
 855                            &_handler_table, &_inc_table,
 856                            compiler,
 857                            env()->comp_level(),
 858                            has_unsafe_access(),
 859                            SharedRuntime::is_wide_vector(max_vector_size())
 860                            );
 861 
 862     if (log() != NULL) // Print code cache state into compiler log
 863       log()->code_cache_state();
 864   }
 865 }
 866 
 867 //------------------------------Compile----------------------------------------
 868 // Compile a runtime stub
 869 Compile::Compile( ciEnv* ci_env,
 870                   TypeFunc_generator generator,
 871                   address stub_function,
 872                   const char *stub_name,
 873                   int is_fancy_jump,
 874                   bool pass_tls,
 875                   bool save_arg_registers,
 876                   bool return_pc )
 877   : Phase(Compiler),
 878     _env(ci_env),
 879     _log(ci_env->log()),
 880     _compile_id(-1),
 881     _save_argument_registers(save_arg_registers),
 882     _method(NULL),
 883     _stub_name(stub_name),
 884     _stub_function(stub_function),
 885     _stub_entry_point(NULL),
 886     _entry_bci(InvocationEntryBci),
 887     _initial_gvn(NULL),
 888     _for_igvn(NULL),
 889     _warm_calls(NULL),
 890     _orig_pc_slot(0),
 891     _orig_pc_slot_offset_in_bytes(0),
 892     _subsume_loads(true),
 893     _do_escape_analysis(false),
 894     _failure_reason(NULL),
 895     _code_buffer("Compile::Fill_buffer"),
 896     _has_method_handle_invokes(false),
 897     _mach_constant_base_node(NULL),
 898     _node_bundling_limit(0),
 899     _node_bundling_base(NULL),
 900     _java_calls(0),
 901     _inner_loops(0),
 902 #ifndef PRODUCT
 903     _trace_opto_output(TraceOptoOutput),
 904     _printer(NULL),
 905 #endif
 906     _dead_node_list(comp_arena()),
 907     _dead_node_count(0),
 908     _congraph(NULL),
 909     _print_inlining_list(NULL),
 910     _print_inlining(0) {
 911   C = this;
 912 
 913 #ifndef PRODUCT
 914   TraceTime t1(NULL, &_t_totalCompilation, TimeCompiler, false);
 915   TraceTime t2(NULL, &_t_stubCompilation, TimeCompiler, false);
 916   set_print_assembly(PrintFrameConverterAssembly);
 917   set_parsed_irreducible_loop(false);
 918 #endif
 919   CompileWrapper cw(this);
 920   Init(/*AliasLevel=*/ 0);
 921   init_tf((*generator)());
 922 
 923   {
 924     // The following is a dummy for the sake of GraphKit::gen_stub
 925     Unique_Node_List for_igvn(comp_arena());
 926     set_for_igvn(&for_igvn);  // not used, but some GraphKit guys push on this
 927     PhaseGVN gvn(Thread::current()->resource_area(),255);
 928     set_initial_gvn(&gvn);    // not significant, but GraphKit guys use it pervasively
 929     gvn.transform_no_reclaim(top());
 930 
 931     GraphKit kit;
 932     kit.gen_stub(stub_function, stub_name, is_fancy_jump, pass_tls, return_pc);
 933   }
 934 
 935   NOT_PRODUCT( verify_graph_edges(); )
 936   Code_Gen();
 937   if (failing())  return;
 938 
 939 
 940   // Entry point will be accessed using compile->stub_entry_point();
 941   if (code_buffer() == NULL) {
 942     Matcher::soft_match_failure();
 943   } else {
 944     if (PrintAssembly && (WizardMode || Verbose))
 945       tty->print_cr("### Stub::%s", stub_name);
 946 
 947     if (!failing()) {
 948       assert(_fixed_slots == 0, "no fixed slots used for runtime stubs");
 949 
 950       // Make the NMethod
 951       // For now we mark the frame as never safe for profile stackwalking
 952       RuntimeStub *rs = RuntimeStub::new_runtime_stub(stub_name,
 953                                                       code_buffer(),
 954                                                       CodeOffsets::frame_never_safe,
 955                                                       // _code_offsets.value(CodeOffsets::Frame_Complete),
 956                                                       frame_size_in_words(),
 957                                                       _oop_map_set,
 958                                                       save_arg_registers);
 959       assert(rs != NULL && rs->is_runtime_stub(), "sanity check");
 960 
 961       _stub_entry_point = rs->entry_point();
 962     }
 963   }
 964 }
 965 
 966 //------------------------------Init-------------------------------------------
 967 // Prepare for a single compilation
 968 void Compile::Init(int aliaslevel) {
 969   _unique  = 0;
 970   _regalloc = NULL;
 971 
 972   _tf      = NULL;  // filled in later
 973   _top     = NULL;  // cached later
 974   _matcher = NULL;  // filled in later
 975   _cfg     = NULL;  // filled in later
 976 
 977   set_24_bit_selection_and_mode(Use24BitFP, false);
 978 
 979   _node_note_array = NULL;
 980   _default_node_notes = NULL;
 981 
 982   _immutable_memory = NULL; // filled in at first inquiry
 983 
 984   // Globally visible Nodes
 985   // First set TOP to NULL to give safe behavior during creation of RootNode
 986   set_cached_top_node(NULL);
 987   set_root(new (this) RootNode());
 988   // Now that you have a Root to point to, create the real TOP
 989   set_cached_top_node( new (this) ConNode(Type::TOP) );
 990   set_recent_alloc(NULL, NULL);
 991 
 992   // Create Debug Information Recorder to record scopes, oopmaps, etc.
 993   env()->set_oop_recorder(new OopRecorder(env()->arena()));
 994   env()->set_debug_info(new DebugInformationRecorder(env()->oop_recorder()));
 995   env()->set_dependencies(new Dependencies(env()));
 996 
 997   _fixed_slots = 0;
 998   set_has_split_ifs(false);
 999   set_has_loops(has_method() && method()->has_loops()); // first approximation
1000   set_has_stringbuilder(false);
1001   _trap_can_recompile = false;  // no traps emitted yet
1002   _major_progress = true; // start out assuming good things will happen
1003   set_has_unsafe_access(false);
1004   set_max_vector_size(0);
1005   Copy::zero_to_bytes(_trap_hist, sizeof(_trap_hist));
1006   set_decompile_count(0);
1007 
1008   set_do_freq_based_layout(BlockLayoutByFrequency || method_has_option("BlockLayoutByFrequency"));
1009   set_num_loop_opts(LoopOptsCount);
1010   set_do_inlining(Inline);
1011   set_max_inline_size(MaxInlineSize);
1012   set_freq_inline_size(FreqInlineSize);
1013   set_do_scheduling(OptoScheduling);
1014   set_do_count_invocations(false);
1015   set_do_method_data_update(false);
1016 
1017   if (debug_info()->recording_non_safepoints()) {
1018     set_node_note_array(new(comp_arena()) GrowableArray<Node_Notes*>
1019                         (comp_arena(), 8, 0, NULL));
1020     set_default_node_notes(Node_Notes::make(this));
1021   }
1022 
1023   // // -- Initialize types before each compile --
1024   // // Update cached type information
1025   // if( _method && _method->constants() )
1026   //   Type::update_loaded_types(_method, _method->constants());
1027 
1028   // Init alias_type map.
1029   if (!_do_escape_analysis && aliaslevel == 3)
1030     aliaslevel = 2;  // No unique types without escape analysis
1031   _AliasLevel = aliaslevel;
1032   const int grow_ats = 16;
1033   _max_alias_types = grow_ats;
1034   _alias_types   = NEW_ARENA_ARRAY(comp_arena(), AliasType*, grow_ats);
1035   AliasType* ats = NEW_ARENA_ARRAY(comp_arena(), AliasType,  grow_ats);
1036   Copy::zero_to_bytes(ats, sizeof(AliasType)*grow_ats);
1037   {
1038     for (int i = 0; i < grow_ats; i++)  _alias_types[i] = &ats[i];
1039   }
1040   // Initialize the first few types.
1041   _alias_types[AliasIdxTop]->Init(AliasIdxTop, NULL);
1042   _alias_types[AliasIdxBot]->Init(AliasIdxBot, TypePtr::BOTTOM);
1043   _alias_types[AliasIdxRaw]->Init(AliasIdxRaw, TypeRawPtr::BOTTOM);
1044   _num_alias_types = AliasIdxRaw+1;
1045   // Zero out the alias type cache.
1046   Copy::zero_to_bytes(_alias_cache, sizeof(_alias_cache));
1047   // A NULL adr_type hits in the cache right away.  Preload the right answer.
1048   probe_alias_cache(NULL)->_index = AliasIdxTop;
1049 
1050   _intrinsics = NULL;
1051   _macro_nodes = new(comp_arena()) GrowableArray<Node*>(comp_arena(), 8,  0, NULL);
1052   _predicate_opaqs = new(comp_arena()) GrowableArray<Node*>(comp_arena(), 8,  0, NULL);
1053   register_library_intrinsics();
1054 }
1055 
1056 //---------------------------init_start----------------------------------------
1057 // Install the StartNode on this compile object.
1058 void Compile::init_start(StartNode* s) {
1059   if (failing())
1060     return; // already failing
1061   assert(s == start(), "");
1062 }
1063 
1064 StartNode* Compile::start() const {
1065   assert(!failing(), "");
1066   for (DUIterator_Fast imax, i = root()->fast_outs(imax); i < imax; i++) {
1067     Node* start = root()->fast_out(i);
1068     if( start->is_Start() )
1069       return start->as_Start();
1070   }
1071   ShouldNotReachHere();
1072   return NULL;
1073 }
1074 
1075 //-------------------------------immutable_memory-------------------------------------
1076 // Access immutable memory
1077 Node* Compile::immutable_memory() {
1078   if (_immutable_memory != NULL) {
1079     return _immutable_memory;
1080   }
1081   StartNode* s = start();
1082   for (DUIterator_Fast imax, i = s->fast_outs(imax); true; i++) {
1083     Node *p = s->fast_out(i);
1084     if (p != s && p->as_Proj()->_con == TypeFunc::Memory) {
1085       _immutable_memory = p;
1086       return _immutable_memory;
1087     }
1088   }
1089   ShouldNotReachHere();
1090   return NULL;
1091 }
1092 
1093 //----------------------set_cached_top_node------------------------------------
1094 // Install the cached top node, and make sure Node::is_top works correctly.
1095 void Compile::set_cached_top_node(Node* tn) {
1096   if (tn != NULL)  verify_top(tn);
1097   Node* old_top = _top;
1098   _top = tn;
1099   // Calling Node::setup_is_top allows the nodes the chance to adjust
1100   // their _out arrays.
1101   if (_top != NULL)     _top->setup_is_top();
1102   if (old_top != NULL)  old_top->setup_is_top();
1103   assert(_top == NULL || top()->is_top(), "");
1104 }
1105 
1106 #ifdef ASSERT
1107 uint Compile::count_live_nodes_by_graph_walk() {
1108   Unique_Node_List useful(comp_arena());
1109   // Get useful node list by walking the graph.
1110   identify_useful_nodes(useful);
1111   return useful.size();
1112 }
1113 
1114 void Compile::print_missing_nodes() {
1115 
1116   // Return if CompileLog is NULL and PrintIdealNodeCount is false.
1117   if ((_log == NULL) && (! PrintIdealNodeCount)) {
1118     return;
1119   }
1120 
1121   // This is an expensive function. It is executed only when the user
1122   // specifies VerifyIdealNodeCount option or otherwise knows the
1123   // additional work that needs to be done to identify reachable nodes
1124   // by walking the flow graph and find the missing ones using
1125   // _dead_node_list.
1126 
1127   Unique_Node_List useful(comp_arena());
1128   // Get useful node list by walking the graph.
1129   identify_useful_nodes(useful);
1130 
1131   uint l_nodes = C->live_nodes();
1132   uint l_nodes_by_walk = useful.size();
1133 
1134   if (l_nodes != l_nodes_by_walk) {
1135     if (_log != NULL) {
1136       _log->begin_head("mismatched_nodes count='%d'", abs((int) (l_nodes - l_nodes_by_walk)));
1137       _log->stamp();
1138       _log->end_head();
1139     }
1140     VectorSet& useful_member_set = useful.member_set();
1141     int last_idx = l_nodes_by_walk;
1142     for (int i = 0; i < last_idx; i++) {
1143       if (useful_member_set.test(i)) {
1144         if (_dead_node_list.test(i)) {
1145           if (_log != NULL) {
1146             _log->elem("mismatched_node_info node_idx='%d' type='both live and dead'", i);
1147           }
1148           if (PrintIdealNodeCount) {
1149             // Print the log message to tty
1150               tty->print_cr("mismatched_node idx='%d' both live and dead'", i);
1151               useful.at(i)->dump();
1152           }
1153         }
1154       }
1155       else if (! _dead_node_list.test(i)) {
1156         if (_log != NULL) {
1157           _log->elem("mismatched_node_info node_idx='%d' type='neither live nor dead'", i);
1158         }
1159         if (PrintIdealNodeCount) {
1160           // Print the log message to tty
1161           tty->print_cr("mismatched_node idx='%d' type='neither live nor dead'", i);
1162         }
1163       }
1164     }
1165     if (_log != NULL) {
1166       _log->tail("mismatched_nodes");
1167     }
1168   }
1169 }
1170 #endif
1171 
1172 #ifndef PRODUCT
1173 void Compile::verify_top(Node* tn) const {
1174   if (tn != NULL) {
1175     assert(tn->is_Con(), "top node must be a constant");
1176     assert(((ConNode*)tn)->type() == Type::TOP, "top node must have correct type");
1177     assert(tn->in(0) != NULL, "must have live top node");
1178   }
1179 }
1180 #endif
1181 
1182 
1183 ///-------------------Managing Per-Node Debug & Profile Info-------------------
1184 
1185 void Compile::grow_node_notes(GrowableArray<Node_Notes*>* arr, int grow_by) {
1186   guarantee(arr != NULL, "");
1187   int num_blocks = arr->length();
1188   if (grow_by < num_blocks)  grow_by = num_blocks;
1189   int num_notes = grow_by * _node_notes_block_size;
1190   Node_Notes* notes = NEW_ARENA_ARRAY(node_arena(), Node_Notes, num_notes);
1191   Copy::zero_to_bytes(notes, num_notes * sizeof(Node_Notes));
1192   while (num_notes > 0) {
1193     arr->append(notes);
1194     notes     += _node_notes_block_size;
1195     num_notes -= _node_notes_block_size;
1196   }
1197   assert(num_notes == 0, "exact multiple, please");
1198 }
1199 
1200 bool Compile::copy_node_notes_to(Node* dest, Node* source) {
1201   if (source == NULL || dest == NULL)  return false;
1202 
1203   if (dest->is_Con())
1204     return false;               // Do not push debug info onto constants.
1205 
1206 #ifdef ASSERT
1207   // Leave a bread crumb trail pointing to the original node:
1208   if (dest != NULL && dest != source && dest->debug_orig() == NULL) {
1209     dest->set_debug_orig(source);
1210   }
1211 #endif
1212 
1213   if (node_note_array() == NULL)
1214     return false;               // Not collecting any notes now.
1215 
1216   // This is a copy onto a pre-existing node, which may already have notes.
1217   // If both nodes have notes, do not overwrite any pre-existing notes.
1218   Node_Notes* source_notes = node_notes_at(source->_idx);
1219   if (source_notes == NULL || source_notes->is_clear())  return false;
1220   Node_Notes* dest_notes   = node_notes_at(dest->_idx);
1221   if (dest_notes == NULL || dest_notes->is_clear()) {
1222     return set_node_notes_at(dest->_idx, source_notes);
1223   }
1224 
1225   Node_Notes merged_notes = (*source_notes);
1226   // The order of operations here ensures that dest notes will win...
1227   merged_notes.update_from(dest_notes);
1228   return set_node_notes_at(dest->_idx, &merged_notes);
1229 }
1230 
1231 
1232 //--------------------------allow_range_check_smearing-------------------------
1233 // Gating condition for coalescing similar range checks.
1234 // Sometimes we try 'speculatively' replacing a series of a range checks by a
1235 // single covering check that is at least as strong as any of them.
1236 // If the optimization succeeds, the simplified (strengthened) range check
1237 // will always succeed.  If it fails, we will deopt, and then give up
1238 // on the optimization.
1239 bool Compile::allow_range_check_smearing() const {
1240   // If this method has already thrown a range-check,
1241   // assume it was because we already tried range smearing
1242   // and it failed.
1243   uint already_trapped = trap_count(Deoptimization::Reason_range_check);
1244   return !already_trapped;
1245 }
1246 
1247 
1248 //------------------------------flatten_alias_type-----------------------------
1249 const TypePtr *Compile::flatten_alias_type( const TypePtr *tj ) const {
1250   int offset = tj->offset();
1251   TypePtr::PTR ptr = tj->ptr();
1252 
1253   // Known instance (scalarizable allocation) alias only with itself.
1254   bool is_known_inst = tj->isa_oopptr() != NULL &&
1255                        tj->is_oopptr()->is_known_instance();
1256 
1257   // Process weird unsafe references.
1258   if (offset == Type::OffsetBot && (tj->isa_instptr() /*|| tj->isa_klassptr()*/)) {
1259     assert(InlineUnsafeOps, "indeterminate pointers come only from unsafe ops");
1260     assert(!is_known_inst, "scalarizable allocation should not have unsafe references");
1261     tj = TypeOopPtr::BOTTOM;
1262     ptr = tj->ptr();
1263     offset = tj->offset();
1264   }
1265 
1266   // Array pointers need some flattening
1267   const TypeAryPtr *ta = tj->isa_aryptr();
1268   if( ta && is_known_inst ) {
1269     if ( offset != Type::OffsetBot &&
1270          offset > arrayOopDesc::length_offset_in_bytes() ) {
1271       offset = Type::OffsetBot; // Flatten constant access into array body only
1272       tj = ta = TypeAryPtr::make(ptr, ta->ary(), ta->klass(), true, offset, ta->instance_id());
1273     }
1274   } else if( ta && _AliasLevel >= 2 ) {
1275     // For arrays indexed by constant indices, we flatten the alias
1276     // space to include all of the array body.  Only the header, klass
1277     // and array length can be accessed un-aliased.
1278     if( offset != Type::OffsetBot ) {
1279       if( ta->const_oop() ) { // MethodData* or Method*
1280         offset = Type::OffsetBot;   // Flatten constant access into array body
1281         tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),ta->ary(),ta->klass(),false,offset);
1282       } else if( offset == arrayOopDesc::length_offset_in_bytes() ) {
1283         // range is OK as-is.
1284         tj = ta = TypeAryPtr::RANGE;
1285       } else if( offset == oopDesc::klass_offset_in_bytes() ) {
1286         tj = TypeInstPtr::KLASS; // all klass loads look alike
1287         ta = TypeAryPtr::RANGE; // generic ignored junk
1288         ptr = TypePtr::BotPTR;
1289       } else if( offset == oopDesc::mark_offset_in_bytes() ) {
1290         tj = TypeInstPtr::MARK;
1291         ta = TypeAryPtr::RANGE; // generic ignored junk
1292         ptr = TypePtr::BotPTR;
1293       } else {                  // Random constant offset into array body
1294         offset = Type::OffsetBot;   // Flatten constant access into array body
1295         tj = ta = TypeAryPtr::make(ptr,ta->ary(),ta->klass(),false,offset);
1296       }
1297     }
1298     // Arrays of fixed size alias with arrays of unknown size.
1299     if (ta->size() != TypeInt::POS) {
1300       const TypeAry *tary = TypeAry::make(ta->elem(), TypeInt::POS);
1301       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,ta->klass(),false,offset);
1302     }
1303     // Arrays of known objects become arrays of unknown objects.
1304     if (ta->elem()->isa_narrowoop() && ta->elem() != TypeNarrowOop::BOTTOM) {
1305       const TypeAry *tary = TypeAry::make(TypeNarrowOop::BOTTOM, ta->size());
1306       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,NULL,false,offset);
1307     }
1308     if (ta->elem()->isa_oopptr() && ta->elem() != TypeInstPtr::BOTTOM) {
1309       const TypeAry *tary = TypeAry::make(TypeInstPtr::BOTTOM, ta->size());
1310       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,NULL,false,offset);
1311     }
1312     // Arrays of bytes and of booleans both use 'bastore' and 'baload' so
1313     // cannot be distinguished by bytecode alone.
1314     if (ta->elem() == TypeInt::BOOL) {
1315       const TypeAry *tary = TypeAry::make(TypeInt::BYTE, ta->size());
1316       ciKlass* aklass = ciTypeArrayKlass::make(T_BYTE);
1317       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,aklass,false,offset);
1318     }
1319     // During the 2nd round of IterGVN, NotNull castings are removed.
1320     // Make sure the Bottom and NotNull variants alias the same.
1321     // Also, make sure exact and non-exact variants alias the same.
1322     if( ptr == TypePtr::NotNull || ta->klass_is_exact() ) {
1323       tj = ta = TypeAryPtr::make(TypePtr::BotPTR,ta->ary(),ta->klass(),false,offset);
1324     }
1325   }
1326 
1327   // Oop pointers need some flattening
1328   const TypeInstPtr *to = tj->isa_instptr();
1329   if( to && _AliasLevel >= 2 && to != TypeOopPtr::BOTTOM ) {
1330     ciInstanceKlass *k = to->klass()->as_instance_klass();
1331     if( ptr == TypePtr::Constant ) {
1332       if (to->klass() != ciEnv::current()->Class_klass() ||
1333           offset < k->size_helper() * wordSize) {
1334         // No constant oop pointers (such as Strings); they alias with
1335         // unknown strings.
1336         assert(!is_known_inst, "not scalarizable allocation");
1337         tj = to = TypeInstPtr::make(TypePtr::BotPTR,to->klass(),false,0,offset);
1338       }
1339     } else if( is_known_inst ) {
1340       tj = to; // Keep NotNull and klass_is_exact for instance type
1341     } else if( ptr == TypePtr::NotNull || to->klass_is_exact() ) {
1342       // During the 2nd round of IterGVN, NotNull castings are removed.
1343       // Make sure the Bottom and NotNull variants alias the same.
1344       // Also, make sure exact and non-exact variants alias the same.
1345       tj = to = TypeInstPtr::make(TypePtr::BotPTR,to->klass(),false,0,offset);
1346     }
1347     // Canonicalize the holder of this field
1348     if (offset >= 0 && offset < instanceOopDesc::base_offset_in_bytes()) {
1349       // First handle header references such as a LoadKlassNode, even if the
1350       // object's klass is unloaded at compile time (4965979).
1351       if (!is_known_inst) { // Do it only for non-instance types
1352         tj = to = TypeInstPtr::make(TypePtr::BotPTR, env()->Object_klass(), false, NULL, offset);
1353       }
1354     } else if (offset < 0 || offset >= k->size_helper() * wordSize) {
1355       // Static fields are in the space above the normal instance
1356       // fields in the java.lang.Class instance.
1357       if (to->klass() != ciEnv::current()->Class_klass()) {
1358         to = NULL;
1359         tj = TypeOopPtr::BOTTOM;
1360         offset = tj->offset();
1361       }
1362     } else {
1363       ciInstanceKlass *canonical_holder = k->get_canonical_holder(offset);
1364       if (!k->equals(canonical_holder) || tj->offset() != offset) {
1365         if( is_known_inst ) {
1366           tj = to = TypeInstPtr::make(to->ptr(), canonical_holder, true, NULL, offset, to->instance_id());
1367         } else {
1368           tj = to = TypeInstPtr::make(to->ptr(), canonical_holder, false, NULL, offset);
1369         }
1370       }
1371     }
1372   }
1373 
1374   // Klass pointers to object array klasses need some flattening
1375   const TypeKlassPtr *tk = tj->isa_klassptr();
1376   if( tk ) {
1377     // If we are referencing a field within a Klass, we need
1378     // to assume the worst case of an Object.  Both exact and
1379     // inexact types must flatten to the same alias class so
1380     // use NotNull as the PTR.
1381     if ( offset == Type::OffsetBot || (offset >= 0 && (size_t)offset < sizeof(Klass)) ) {
1382 
1383       tj = tk = TypeKlassPtr::make(TypePtr::NotNull,
1384                                    TypeKlassPtr::OBJECT->klass(),
1385                                    offset);
1386     }
1387 
1388     ciKlass* klass = tk->klass();
1389     if( klass->is_obj_array_klass() ) {
1390       ciKlass* k = TypeAryPtr::OOPS->klass();
1391       if( !k || !k->is_loaded() )                  // Only fails for some -Xcomp runs
1392         k = TypeInstPtr::BOTTOM->klass();
1393       tj = tk = TypeKlassPtr::make( TypePtr::NotNull, k, offset );
1394     }
1395 
1396     // Check for precise loads from the primary supertype array and force them
1397     // to the supertype cache alias index.  Check for generic array loads from
1398     // the primary supertype array and also force them to the supertype cache
1399     // alias index.  Since the same load can reach both, we need to merge
1400     // these 2 disparate memories into the same alias class.  Since the
1401     // primary supertype array is read-only, there's no chance of confusion
1402     // where we bypass an array load and an array store.
1403     int primary_supers_offset = in_bytes(Klass::primary_supers_offset());
1404     if (offset == Type::OffsetBot ||
1405         (offset >= primary_supers_offset &&
1406          offset < (int)(primary_supers_offset + Klass::primary_super_limit() * wordSize)) ||
1407         offset == (int)in_bytes(Klass::secondary_super_cache_offset())) {
1408       offset = in_bytes(Klass::secondary_super_cache_offset());
1409       tj = tk = TypeKlassPtr::make( TypePtr::NotNull, tk->klass(), offset );
1410     }
1411   }
1412 
1413   // Flatten all Raw pointers together.
1414   if (tj->base() == Type::RawPtr)
1415     tj = TypeRawPtr::BOTTOM;
1416 
1417   if (tj->base() == Type::AnyPtr)
1418     tj = TypePtr::BOTTOM;      // An error, which the caller must check for.
1419 
1420   // Flatten all to bottom for now
1421   switch( _AliasLevel ) {
1422   case 0:
1423     tj = TypePtr::BOTTOM;
1424     break;
1425   case 1:                       // Flatten to: oop, static, field or array
1426     switch (tj->base()) {
1427     //case Type::AryPtr: tj = TypeAryPtr::RANGE;    break;
1428     case Type::RawPtr:   tj = TypeRawPtr::BOTTOM;   break;
1429     case Type::AryPtr:   // do not distinguish arrays at all
1430     case Type::InstPtr:  tj = TypeInstPtr::BOTTOM;  break;
1431     case Type::KlassPtr: tj = TypeKlassPtr::OBJECT; break;
1432     case Type::AnyPtr:   tj = TypePtr::BOTTOM;      break;  // caller checks it
1433     default: ShouldNotReachHere();
1434     }
1435     break;
1436   case 2:                       // No collapsing at level 2; keep all splits
1437   case 3:                       // No collapsing at level 3; keep all splits
1438     break;
1439   default:
1440     Unimplemented();
1441   }
1442 
1443   offset = tj->offset();
1444   assert( offset != Type::OffsetTop, "Offset has fallen from constant" );
1445 
1446   assert( (offset != Type::OffsetBot && tj->base() != Type::AryPtr) ||
1447           (offset == Type::OffsetBot && tj->base() == Type::AryPtr) ||
1448           (offset == Type::OffsetBot && tj == TypeOopPtr::BOTTOM) ||
1449           (offset == Type::OffsetBot && tj == TypePtr::BOTTOM) ||
1450           (offset == oopDesc::mark_offset_in_bytes() && tj->base() == Type::AryPtr) ||
1451           (offset == oopDesc::klass_offset_in_bytes() && tj->base() == Type::AryPtr) ||
1452           (offset == arrayOopDesc::length_offset_in_bytes() && tj->base() == Type::AryPtr)  ,
1453           "For oops, klasses, raw offset must be constant; for arrays the offset is never known" );
1454   assert( tj->ptr() != TypePtr::TopPTR &&
1455           tj->ptr() != TypePtr::AnyNull &&
1456           tj->ptr() != TypePtr::Null, "No imprecise addresses" );
1457 //    assert( tj->ptr() != TypePtr::Constant ||
1458 //            tj->base() == Type::RawPtr ||
1459 //            tj->base() == Type::KlassPtr, "No constant oop addresses" );
1460 
1461   return tj;
1462 }
1463 
1464 void Compile::AliasType::Init(int i, const TypePtr* at) {
1465   _index = i;
1466   _adr_type = at;
1467   _field = NULL;
1468   _is_rewritable = true; // default
1469   const TypeOopPtr *atoop = (at != NULL) ? at->isa_oopptr() : NULL;
1470   if (atoop != NULL && atoop->is_known_instance()) {
1471     const TypeOopPtr *gt = atoop->cast_to_instance_id(TypeOopPtr::InstanceBot);
1472     _general_index = Compile::current()->get_alias_index(gt);
1473   } else {
1474     _general_index = 0;
1475   }
1476 }
1477 
1478 //---------------------------------print_on------------------------------------
1479 #ifndef PRODUCT
1480 void Compile::AliasType::print_on(outputStream* st) {
1481   if (index() < 10)
1482         st->print("@ <%d> ", index());
1483   else  st->print("@ <%d>",  index());
1484   st->print(is_rewritable() ? "   " : " RO");
1485   int offset = adr_type()->offset();
1486   if (offset == Type::OffsetBot)
1487         st->print(" +any");
1488   else  st->print(" +%-3d", offset);
1489   st->print(" in ");
1490   adr_type()->dump_on(st);
1491   const TypeOopPtr* tjp = adr_type()->isa_oopptr();
1492   if (field() != NULL && tjp) {
1493     if (tjp->klass()  != field()->holder() ||
1494         tjp->offset() != field()->offset_in_bytes()) {
1495       st->print(" != ");
1496       field()->print();
1497       st->print(" ***");
1498     }
1499   }
1500 }
1501 
1502 void print_alias_types() {
1503   Compile* C = Compile::current();
1504   tty->print_cr("--- Alias types, AliasIdxBot .. %d", C->num_alias_types()-1);
1505   for (int idx = Compile::AliasIdxBot; idx < C->num_alias_types(); idx++) {
1506     C->alias_type(idx)->print_on(tty);
1507     tty->cr();
1508   }
1509 }
1510 #endif
1511 
1512 
1513 //----------------------------probe_alias_cache--------------------------------
1514 Compile::AliasCacheEntry* Compile::probe_alias_cache(const TypePtr* adr_type) {
1515   intptr_t key = (intptr_t) adr_type;
1516   key ^= key >> logAliasCacheSize;
1517   return &_alias_cache[key & right_n_bits(logAliasCacheSize)];
1518 }
1519 
1520 
1521 //-----------------------------grow_alias_types--------------------------------
1522 void Compile::grow_alias_types() {
1523   const int old_ats  = _max_alias_types; // how many before?
1524   const int new_ats  = old_ats;          // how many more?
1525   const int grow_ats = old_ats+new_ats;  // how many now?
1526   _max_alias_types = grow_ats;
1527   _alias_types =  REALLOC_ARENA_ARRAY(comp_arena(), AliasType*, _alias_types, old_ats, grow_ats);
1528   AliasType* ats =    NEW_ARENA_ARRAY(comp_arena(), AliasType, new_ats);
1529   Copy::zero_to_bytes(ats, sizeof(AliasType)*new_ats);
1530   for (int i = 0; i < new_ats; i++)  _alias_types[old_ats+i] = &ats[i];
1531 }
1532 
1533 
1534 //--------------------------------find_alias_type------------------------------
1535 Compile::AliasType* Compile::find_alias_type(const TypePtr* adr_type, bool no_create, ciField* original_field) {
1536   if (_AliasLevel == 0)
1537     return alias_type(AliasIdxBot);
1538 
1539   AliasCacheEntry* ace = probe_alias_cache(adr_type);
1540   if (ace->_adr_type == adr_type) {
1541     return alias_type(ace->_index);
1542   }
1543 
1544   // Handle special cases.
1545   if (adr_type == NULL)             return alias_type(AliasIdxTop);
1546   if (adr_type == TypePtr::BOTTOM)  return alias_type(AliasIdxBot);
1547 
1548   // Do it the slow way.
1549   const TypePtr* flat = flatten_alias_type(adr_type);
1550 
1551 #ifdef ASSERT
1552   assert(flat == flatten_alias_type(flat), "idempotent");
1553   assert(flat != TypePtr::BOTTOM,     "cannot alias-analyze an untyped ptr");
1554   if (flat->isa_oopptr() && !flat->isa_klassptr()) {
1555     const TypeOopPtr* foop = flat->is_oopptr();
1556     // Scalarizable allocations have exact klass always.
1557     bool exact = !foop->klass_is_exact() || foop->is_known_instance();
1558     const TypePtr* xoop = foop->cast_to_exactness(exact)->is_ptr();
1559     assert(foop == flatten_alias_type(xoop), "exactness must not affect alias type");
1560   }
1561   assert(flat == flatten_alias_type(flat), "exact bit doesn't matter");
1562 #endif
1563 
1564   int idx = AliasIdxTop;
1565   for (int i = 0; i < num_alias_types(); i++) {
1566     if (alias_type(i)->adr_type() == flat) {
1567       idx = i;
1568       break;
1569     }
1570   }
1571 
1572   if (idx == AliasIdxTop) {
1573     if (no_create)  return NULL;
1574     // Grow the array if necessary.
1575     if (_num_alias_types == _max_alias_types)  grow_alias_types();
1576     // Add a new alias type.
1577     idx = _num_alias_types++;
1578     _alias_types[idx]->Init(idx, flat);
1579     if (flat == TypeInstPtr::KLASS)  alias_type(idx)->set_rewritable(false);
1580     if (flat == TypeAryPtr::RANGE)   alias_type(idx)->set_rewritable(false);
1581     if (flat->isa_instptr()) {
1582       if (flat->offset() == java_lang_Class::klass_offset_in_bytes()
1583           && flat->is_instptr()->klass() == env()->Class_klass())
1584         alias_type(idx)->set_rewritable(false);
1585     }
1586     if (flat->isa_klassptr()) {
1587       if (flat->offset() == in_bytes(Klass::super_check_offset_offset()))
1588         alias_type(idx)->set_rewritable(false);
1589       if (flat->offset() == in_bytes(Klass::modifier_flags_offset()))
1590         alias_type(idx)->set_rewritable(false);
1591       if (flat->offset() == in_bytes(Klass::access_flags_offset()))
1592         alias_type(idx)->set_rewritable(false);
1593       if (flat->offset() == in_bytes(Klass::java_mirror_offset()))
1594         alias_type(idx)->set_rewritable(false);
1595     }
1596     // %%% (We would like to finalize JavaThread::threadObj_offset(),
1597     // but the base pointer type is not distinctive enough to identify
1598     // references into JavaThread.)
1599 
1600     // Check for final fields.
1601     const TypeInstPtr* tinst = flat->isa_instptr();
1602     if (tinst && tinst->offset() >= instanceOopDesc::base_offset_in_bytes()) {
1603       ciField* field;
1604       if (tinst->const_oop() != NULL &&
1605           tinst->klass() == ciEnv::current()->Class_klass() &&
1606           tinst->offset() >= (tinst->klass()->as_instance_klass()->size_helper() * wordSize)) {
1607         // static field
1608         ciInstanceKlass* k = tinst->const_oop()->as_instance()->java_lang_Class_klass()->as_instance_klass();
1609         field = k->get_field_by_offset(tinst->offset(), true);
1610       } else {
1611         ciInstanceKlass *k = tinst->klass()->as_instance_klass();
1612         field = k->get_field_by_offset(tinst->offset(), false);
1613       }
1614       assert(field == NULL ||
1615              original_field == NULL ||
1616              (field->holder() == original_field->holder() &&
1617               field->offset() == original_field->offset() &&
1618               field->is_static() == original_field->is_static()), "wrong field?");
1619       // Set field() and is_rewritable() attributes.
1620       if (field != NULL)  alias_type(idx)->set_field(field);
1621     }
1622   }
1623 
1624   // Fill the cache for next time.
1625   ace->_adr_type = adr_type;
1626   ace->_index    = idx;
1627   assert(alias_type(adr_type) == alias_type(idx),  "type must be installed");
1628 
1629   // Might as well try to fill the cache for the flattened version, too.
1630   AliasCacheEntry* face = probe_alias_cache(flat);
1631   if (face->_adr_type == NULL) {
1632     face->_adr_type = flat;
1633     face->_index    = idx;
1634     assert(alias_type(flat) == alias_type(idx), "flat type must work too");
1635   }
1636 
1637   return alias_type(idx);
1638 }
1639 
1640 
1641 Compile::AliasType* Compile::alias_type(ciField* field) {
1642   const TypeOopPtr* t;
1643   if (field->is_static())
1644     t = TypeInstPtr::make(field->holder()->java_mirror());
1645   else
1646     t = TypeOopPtr::make_from_klass_raw(field->holder());
1647   AliasType* atp = alias_type(t->add_offset(field->offset_in_bytes()), field);
1648   assert(field->is_final() == !atp->is_rewritable(), "must get the rewritable bits correct");
1649   return atp;
1650 }
1651 
1652 
1653 //------------------------------have_alias_type--------------------------------
1654 bool Compile::have_alias_type(const TypePtr* adr_type) {
1655   AliasCacheEntry* ace = probe_alias_cache(adr_type);
1656   if (ace->_adr_type == adr_type) {
1657     return true;
1658   }
1659 
1660   // Handle special cases.
1661   if (adr_type == NULL)             return true;
1662   if (adr_type == TypePtr::BOTTOM)  return true;
1663 
1664   return find_alias_type(adr_type, true, NULL) != NULL;
1665 }
1666 
1667 //-----------------------------must_alias--------------------------------------
1668 // True if all values of the given address type are in the given alias category.
1669 bool Compile::must_alias(const TypePtr* adr_type, int alias_idx) {
1670   if (alias_idx == AliasIdxBot)         return true;  // the universal category
1671   if (adr_type == NULL)                 return true;  // NULL serves as TypePtr::TOP
1672   if (alias_idx == AliasIdxTop)         return false; // the empty category
1673   if (adr_type->base() == Type::AnyPtr) return false; // TypePtr::BOTTOM or its twins
1674 
1675   // the only remaining possible overlap is identity
1676   int adr_idx = get_alias_index(adr_type);
1677   assert(adr_idx != AliasIdxBot && adr_idx != AliasIdxTop, "");
1678   assert(adr_idx == alias_idx ||
1679          (alias_type(alias_idx)->adr_type() != TypeOopPtr::BOTTOM
1680           && adr_type                       != TypeOopPtr::BOTTOM),
1681          "should not be testing for overlap with an unsafe pointer");
1682   return adr_idx == alias_idx;
1683 }
1684 
1685 //------------------------------can_alias--------------------------------------
1686 // True if any values of the given address type are in the given alias category.
1687 bool Compile::can_alias(const TypePtr* adr_type, int alias_idx) {
1688   if (alias_idx == AliasIdxTop)         return false; // the empty category
1689   if (adr_type == NULL)                 return false; // NULL serves as TypePtr::TOP
1690   if (alias_idx == AliasIdxBot)         return true;  // the universal category
1691   if (adr_type->base() == Type::AnyPtr) return true;  // TypePtr::BOTTOM or its twins
1692 
1693   // the only remaining possible overlap is identity
1694   int adr_idx = get_alias_index(adr_type);
1695   assert(adr_idx != AliasIdxBot && adr_idx != AliasIdxTop, "");
1696   return adr_idx == alias_idx;
1697 }
1698 
1699 
1700 
1701 //---------------------------pop_warm_call-------------------------------------
1702 WarmCallInfo* Compile::pop_warm_call() {
1703   WarmCallInfo* wci = _warm_calls;
1704   if (wci != NULL)  _warm_calls = wci->remove_from(wci);
1705   return wci;
1706 }
1707 
1708 //----------------------------Inline_Warm--------------------------------------
1709 int Compile::Inline_Warm() {
1710   // If there is room, try to inline some more warm call sites.
1711   // %%% Do a graph index compaction pass when we think we're out of space?
1712   if (!InlineWarmCalls)  return 0;
1713 
1714   int calls_made_hot = 0;
1715   int room_to_grow   = NodeCountInliningCutoff - unique();
1716   int amount_to_grow = MIN2(room_to_grow, (int)NodeCountInliningStep);
1717   int amount_grown   = 0;
1718   WarmCallInfo* call;
1719   while (amount_to_grow > 0 && (call = pop_warm_call()) != NULL) {
1720     int est_size = (int)call->size();
1721     if (est_size > (room_to_grow - amount_grown)) {
1722       // This one won't fit anyway.  Get rid of it.
1723       call->make_cold();
1724       continue;
1725     }
1726     call->make_hot();
1727     calls_made_hot++;
1728     amount_grown   += est_size;
1729     amount_to_grow -= est_size;
1730   }
1731 
1732   if (calls_made_hot > 0)  set_major_progress();
1733   return calls_made_hot;
1734 }
1735 
1736 
1737 //----------------------------Finish_Warm--------------------------------------
1738 void Compile::Finish_Warm() {
1739   if (!InlineWarmCalls)  return;
1740   if (failing())  return;
1741   if (warm_calls() == NULL)  return;
1742 
1743   // Clean up loose ends, if we are out of space for inlining.
1744   WarmCallInfo* call;
1745   while ((call = pop_warm_call()) != NULL) {
1746     call->make_cold();
1747   }
1748 }
1749 
1750 //---------------------cleanup_loop_predicates-----------------------
1751 // Remove the opaque nodes that protect the predicates so that all unused
1752 // checks and uncommon_traps will be eliminated from the ideal graph
1753 void Compile::cleanup_loop_predicates(PhaseIterGVN &igvn) {
1754   if (predicate_count()==0) return;
1755   for (int i = predicate_count(); i > 0; i--) {
1756     Node * n = predicate_opaque1_node(i-1);
1757     assert(n->Opcode() == Op_Opaque1, "must be");
1758     igvn.replace_node(n, n->in(1));
1759   }
1760   assert(predicate_count()==0, "should be clean!");
1761 }
1762 
1763 //------------------------------Optimize---------------------------------------
1764 // Given a graph, optimize it.
1765 void Compile::Optimize() {
1766   TracePhase t1("optimizer", &_t_optimizer, true);
1767 
1768 #ifndef PRODUCT
1769   if (env()->break_at_compile()) {
1770     BREAKPOINT;
1771   }
1772 
1773 #endif
1774 
1775   ResourceMark rm;
1776   int          loop_opts_cnt;
1777 
1778   NOT_PRODUCT( verify_graph_edges(); )
1779 
1780   print_method("After Parsing");
1781 
1782  {
1783   // Iterative Global Value Numbering, including ideal transforms
1784   // Initialize IterGVN with types and values from parse-time GVN
1785   PhaseIterGVN igvn(initial_gvn());
1786   {
1787     NOT_PRODUCT( TracePhase t2("iterGVN", &_t_iterGVN, TimeCompiler); )
1788     igvn.optimize();
1789   }
1790 
1791   print_method("Iter GVN 1", 2);
1792 
1793   if (failing())  return;
1794 
1795   // Perform escape analysis
1796   if (_do_escape_analysis && ConnectionGraph::has_candidates(this)) {
1797     if (has_loops()) {
1798       // Cleanup graph (remove dead nodes).
1799       TracePhase t2("idealLoop", &_t_idealLoop, true);
1800       PhaseIdealLoop ideal_loop( igvn, false, true );
1801       if (major_progress()) print_method("PhaseIdealLoop before EA", 2);
1802       if (failing())  return;
1803     }
1804     ConnectionGraph::do_analysis(this, &igvn);
1805 
1806     if (failing())  return;
1807 
1808     // Optimize out fields loads from scalar replaceable allocations.
1809     igvn.optimize();
1810     print_method("Iter GVN after EA", 2);
1811 
1812     if (failing())  return;
1813 
1814     if (congraph() != NULL && macro_count() > 0) {
1815       NOT_PRODUCT( TracePhase t2("macroEliminate", &_t_macroEliminate, TimeCompiler); )
1816       PhaseMacroExpand mexp(igvn);
1817       mexp.eliminate_macro_nodes();
1818       igvn.set_delay_transform(false);
1819 
1820       igvn.optimize();
1821       print_method("Iter GVN after eliminating allocations and locks", 2);
1822 
1823       if (failing())  return;
1824     }
1825   }
1826 
1827   // Loop transforms on the ideal graph.  Range Check Elimination,
1828   // peeling, unrolling, etc.
1829 
1830   // Set loop opts counter
1831   loop_opts_cnt = num_loop_opts();
1832   if((loop_opts_cnt > 0) && (has_loops() || has_split_ifs())) {
1833     {
1834       TracePhase t2("idealLoop", &_t_idealLoop, true);
1835       PhaseIdealLoop ideal_loop( igvn, true );
1836       loop_opts_cnt--;
1837       if (major_progress()) print_method("PhaseIdealLoop 1", 2);
1838       if (failing())  return;
1839     }
1840     // Loop opts pass if partial peeling occurred in previous pass
1841     if(PartialPeelLoop && major_progress() && (loop_opts_cnt > 0)) {
1842       TracePhase t3("idealLoop", &_t_idealLoop, true);
1843       PhaseIdealLoop ideal_loop( igvn, false );
1844       loop_opts_cnt--;
1845       if (major_progress()) print_method("PhaseIdealLoop 2", 2);
1846       if (failing())  return;
1847     }
1848     // Loop opts pass for loop-unrolling before CCP
1849     if(major_progress() && (loop_opts_cnt > 0)) {
1850       TracePhase t4("idealLoop", &_t_idealLoop, true);
1851       PhaseIdealLoop ideal_loop( igvn, false );
1852       loop_opts_cnt--;
1853       if (major_progress()) print_method("PhaseIdealLoop 3", 2);
1854     }
1855     if (!failing()) {
1856       // Verify that last round of loop opts produced a valid graph
1857       NOT_PRODUCT( TracePhase t2("idealLoopVerify", &_t_idealLoopVerify, TimeCompiler); )
1858       PhaseIdealLoop::verify(igvn);
1859     }
1860   }
1861   if (failing())  return;
1862 
1863   // Conditional Constant Propagation;
1864   PhaseCCP ccp( &igvn );
1865   assert( true, "Break here to ccp.dump_nodes_and_types(_root,999,1)");
1866   {
1867     TracePhase t2("ccp", &_t_ccp, true);
1868     ccp.do_transform();
1869   }
1870   print_method("PhaseCPP 1", 2);
1871 
1872   assert( true, "Break here to ccp.dump_old2new_map()");
1873 
1874   // Iterative Global Value Numbering, including ideal transforms
1875   {
1876     NOT_PRODUCT( TracePhase t2("iterGVN2", &_t_iterGVN2, TimeCompiler); )
1877     igvn = ccp;
1878     igvn.optimize();
1879   }
1880 
1881   print_method("Iter GVN 2", 2);
1882 
1883   if (failing())  return;
1884 
1885   // Loop transforms on the ideal graph.  Range Check Elimination,
1886   // peeling, unrolling, etc.
1887   if(loop_opts_cnt > 0) {
1888     debug_only( int cnt = 0; );
1889     while(major_progress() && (loop_opts_cnt > 0)) {
1890       TracePhase t2("idealLoop", &_t_idealLoop, true);
1891       assert( cnt++ < 40, "infinite cycle in loop optimization" );
1892       PhaseIdealLoop ideal_loop( igvn, true);
1893       loop_opts_cnt--;
1894       if (major_progress()) print_method("PhaseIdealLoop iterations", 2);
1895       if (failing())  return;
1896     }
1897   }
1898 
1899   {
1900     // Verify that all previous optimizations produced a valid graph
1901     // at least to this point, even if no loop optimizations were done.
1902     NOT_PRODUCT( TracePhase t2("idealLoopVerify", &_t_idealLoopVerify, TimeCompiler); )
1903     PhaseIdealLoop::verify(igvn);
1904   }
1905 
1906   {
1907     NOT_PRODUCT( TracePhase t2("macroExpand", &_t_macroExpand, TimeCompiler); )
1908     PhaseMacroExpand  mex(igvn);
1909     if (mex.expand_macro_nodes()) {
1910       assert(failing(), "must bail out w/ explicit message");
1911       return;
1912     }
1913   }
1914 
1915  } // (End scope of igvn; run destructor if necessary for asserts.)
1916 
1917   // A method with only infinite loops has no edges entering loops from root
1918   {
1919     NOT_PRODUCT( TracePhase t2("graphReshape", &_t_graphReshaping, TimeCompiler); )
1920     if (final_graph_reshaping()) {
1921       assert(failing(), "must bail out w/ explicit message");
1922       return;
1923     }
1924   }
1925 
1926   print_method("Optimize finished", 2);
1927 }
1928 
1929 
1930 //------------------------------Code_Gen---------------------------------------
1931 // Given a graph, generate code for it
1932 void Compile::Code_Gen() {
1933   if (failing())  return;
1934 
1935   // Perform instruction selection.  You might think we could reclaim Matcher
1936   // memory PDQ, but actually the Matcher is used in generating spill code.
1937   // Internals of the Matcher (including some VectorSets) must remain live
1938   // for awhile - thus I cannot reclaim Matcher memory lest a VectorSet usage
1939   // set a bit in reclaimed memory.
1940 
1941   // In debug mode can dump m._nodes.dump() for mapping of ideal to machine
1942   // nodes.  Mapping is only valid at the root of each matched subtree.
1943   NOT_PRODUCT( verify_graph_edges(); )
1944 
1945   Node_List proj_list;
1946   Matcher m(proj_list);
1947   _matcher = &m;
1948   {
1949     TracePhase t2("matcher", &_t_matcher, true);
1950     m.match();
1951   }
1952   // In debug mode can dump m._nodes.dump() for mapping of ideal to machine
1953   // nodes.  Mapping is only valid at the root of each matched subtree.
1954   NOT_PRODUCT( verify_graph_edges(); )
1955 
1956   // If you have too many nodes, or if matching has failed, bail out
1957   check_node_count(0, "out of nodes matching instructions");
1958   if (failing())  return;
1959 
1960   // Build a proper-looking CFG
1961   PhaseCFG cfg(node_arena(), root(), m);
1962   _cfg = &cfg;
1963   {
1964     NOT_PRODUCT( TracePhase t2("scheduler", &_t_scheduler, TimeCompiler); )
1965     cfg.Dominators();
1966     if (failing())  return;
1967 
1968     NOT_PRODUCT( verify_graph_edges(); )
1969 
1970     cfg.Estimate_Block_Frequency();
1971     cfg.GlobalCodeMotion(m,unique(),proj_list);
1972     if (failing())  return;
1973 
1974     print_method("Global code motion", 2);
1975 
1976     NOT_PRODUCT( verify_graph_edges(); )
1977 
1978     debug_only( cfg.verify(); )
1979   }
1980   NOT_PRODUCT( verify_graph_edges(); )
1981 
1982   PhaseChaitin regalloc(unique(),cfg,m);
1983   _regalloc = &regalloc;
1984   {
1985     TracePhase t2("regalloc", &_t_registerAllocation, true);
1986     // Perform any platform dependent preallocation actions.  This is used,
1987     // for example, to avoid taking an implicit null pointer exception
1988     // using the frame pointer on win95.
1989     _regalloc->pd_preallocate_hook();
1990 
1991     // Perform register allocation.  After Chaitin, use-def chains are
1992     // no longer accurate (at spill code) and so must be ignored.
1993     // Node->LRG->reg mappings are still accurate.
1994     _regalloc->Register_Allocate();
1995 
1996     // Bail out if the allocator builds too many nodes
1997     if (failing())  return;
1998   }
1999 
2000   // Prior to register allocation we kept empty basic blocks in case the
2001   // the allocator needed a place to spill.  After register allocation we
2002   // are not adding any new instructions.  If any basic block is empty, we
2003   // can now safely remove it.
2004   {
2005     NOT_PRODUCT( TracePhase t2("blockOrdering", &_t_blockOrdering, TimeCompiler); )
2006     cfg.remove_empty();
2007     if (do_freq_based_layout()) {
2008       PhaseBlockLayout layout(cfg);
2009     } else {
2010       cfg.set_loop_alignment();
2011     }
2012     cfg.fixup_flow();
2013   }
2014 
2015   // Perform any platform dependent postallocation verifications.
2016   debug_only( _regalloc->pd_postallocate_verify_hook(); )
2017 
2018   // Apply peephole optimizations
2019   if( OptoPeephole ) {
2020     NOT_PRODUCT( TracePhase t2("peephole", &_t_peephole, TimeCompiler); )
2021     PhasePeephole peep( _regalloc, cfg);
2022     peep.do_transform();
2023   }
2024 
2025   // Convert Nodes to instruction bits in a buffer
2026   {
2027     // %%%% workspace merge brought two timers together for one job
2028     TracePhase t2a("output", &_t_output, true);
2029     NOT_PRODUCT( TraceTime t2b(NULL, &_t_codeGeneration, TimeCompiler, false); )
2030     Output();
2031   }
2032 
2033   print_method("Final Code");
2034 
2035   // He's dead, Jim.
2036   _cfg     = (PhaseCFG*)0xdeadbeef;
2037   _regalloc = (PhaseChaitin*)0xdeadbeef;
2038 }
2039 
2040 
2041 //------------------------------dump_asm---------------------------------------
2042 // Dump formatted assembly
2043 #ifndef PRODUCT
2044 void Compile::dump_asm(int *pcs, uint pc_limit) {
2045   bool cut_short = false;
2046   tty->print_cr("#");
2047   tty->print("#  ");  _tf->dump();  tty->cr();
2048   tty->print_cr("#");
2049 
2050   // For all blocks
2051   int pc = 0x0;                 // Program counter
2052   char starts_bundle = ' ';
2053   _regalloc->dump_frame();
2054 
2055   Node *n = NULL;
2056   for( uint i=0; i<_cfg->_num_blocks; i++ ) {
2057     if (VMThread::should_terminate()) { cut_short = true; break; }
2058     Block *b = _cfg->_blocks[i];
2059     if (b->is_connector() && !Verbose) continue;
2060     n = b->_nodes[0];
2061     if (pcs && n->_idx < pc_limit)
2062       tty->print("%3.3x   ", pcs[n->_idx]);
2063     else
2064       tty->print("      ");
2065     b->dump_head( &_cfg->_bbs );
2066     if (b->is_connector()) {
2067       tty->print_cr("        # Empty connector block");
2068     } else if (b->num_preds() == 2 && b->pred(1)->is_CatchProj() && b->pred(1)->as_CatchProj()->_con == CatchProjNode::fall_through_index) {
2069       tty->print_cr("        # Block is sole successor of call");
2070     }
2071 
2072     // For all instructions
2073     Node *delay = NULL;
2074     for( uint j = 0; j<b->_nodes.size(); j++ ) {
2075       if (VMThread::should_terminate()) { cut_short = true; break; }
2076       n = b->_nodes[j];
2077       if (valid_bundle_info(n)) {
2078         Bundle *bundle = node_bundling(n);
2079         if (bundle->used_in_unconditional_delay()) {
2080           delay = n;
2081           continue;
2082         }
2083         if (bundle->starts_bundle())
2084           starts_bundle = '+';
2085       }
2086 
2087       if (WizardMode) n->dump();
2088 
2089       if( !n->is_Region() &&    // Dont print in the Assembly
2090           !n->is_Phi() &&       // a few noisely useless nodes
2091           !n->is_Proj() &&
2092           !n->is_MachTemp() &&
2093           !n->is_SafePointScalarObject() &&
2094           !n->is_Catch() &&     // Would be nice to print exception table targets
2095           !n->is_MergeMem() &&  // Not very interesting
2096           !n->is_top() &&       // Debug info table constants
2097           !(n->is_Con() && !n->is_Mach())// Debug info table constants
2098           ) {
2099         if (pcs && n->_idx < pc_limit)
2100           tty->print("%3.3x", pcs[n->_idx]);
2101         else
2102           tty->print("   ");
2103         tty->print(" %c ", starts_bundle);
2104         starts_bundle = ' ';
2105         tty->print("\t");
2106         n->format(_regalloc, tty);
2107         tty->cr();
2108       }
2109 
2110       // If we have an instruction with a delay slot, and have seen a delay,
2111       // then back up and print it
2112       if (valid_bundle_info(n) && node_bundling(n)->use_unconditional_delay()) {
2113         assert(delay != NULL, "no unconditional delay instruction");
2114         if (WizardMode) delay->dump();
2115 
2116         if (node_bundling(delay)->starts_bundle())
2117           starts_bundle = '+';
2118         if (pcs && n->_idx < pc_limit)
2119           tty->print("%3.3x", pcs[n->_idx]);
2120         else
2121           tty->print("   ");
2122         tty->print(" %c ", starts_bundle);
2123         starts_bundle = ' ';
2124         tty->print("\t");
2125         delay->format(_regalloc, tty);
2126         tty->print_cr("");
2127         delay = NULL;
2128       }
2129 
2130       // Dump the exception table as well
2131       if( n->is_Catch() && (Verbose || WizardMode) ) {
2132         // Print the exception table for this offset
2133         _handler_table.print_subtable_for(pc);
2134       }
2135     }
2136 
2137     if (pcs && n->_idx < pc_limit)
2138       tty->print_cr("%3.3x", pcs[n->_idx]);
2139     else
2140       tty->print_cr("");
2141 
2142     assert(cut_short || delay == NULL, "no unconditional delay branch");
2143 
2144   } // End of per-block dump
2145   tty->print_cr("");
2146 
2147   if (cut_short)  tty->print_cr("*** disassembly is cut short ***");
2148 }
2149 #endif
2150 
2151 //------------------------------Final_Reshape_Counts---------------------------
2152 // This class defines counters to help identify when a method
2153 // may/must be executed using hardware with only 24-bit precision.
2154 struct Final_Reshape_Counts : public StackObj {
2155   int  _call_count;             // count non-inlined 'common' calls
2156   int  _float_count;            // count float ops requiring 24-bit precision
2157   int  _double_count;           // count double ops requiring more precision
2158   int  _java_call_count;        // count non-inlined 'java' calls
2159   int  _inner_loop_count;       // count loops which need alignment
2160   VectorSet _visited;           // Visitation flags
2161   Node_List _tests;             // Set of IfNodes & PCTableNodes
2162 
2163   Final_Reshape_Counts() :
2164     _call_count(0), _float_count(0), _double_count(0),
2165     _java_call_count(0), _inner_loop_count(0),
2166     _visited( Thread::current()->resource_area() ) { }
2167 
2168   void inc_call_count  () { _call_count  ++; }
2169   void inc_float_count () { _float_count ++; }
2170   void inc_double_count() { _double_count++; }
2171   void inc_java_call_count() { _java_call_count++; }
2172   void inc_inner_loop_count() { _inner_loop_count++; }
2173 
2174   int  get_call_count  () const { return _call_count  ; }
2175   int  get_float_count () const { return _float_count ; }
2176   int  get_double_count() const { return _double_count; }
2177   int  get_java_call_count() const { return _java_call_count; }
2178   int  get_inner_loop_count() const { return _inner_loop_count; }
2179 };
2180 
2181 static bool oop_offset_is_sane(const TypeInstPtr* tp) {
2182   ciInstanceKlass *k = tp->klass()->as_instance_klass();
2183   // Make sure the offset goes inside the instance layout.
2184   return k->contains_field_offset(tp->offset());
2185   // Note that OffsetBot and OffsetTop are very negative.
2186 }
2187 
2188 // Eliminate trivially redundant StoreCMs and accumulate their
2189 // precedence edges.
2190 void Compile::eliminate_redundant_card_marks(Node* n) {
2191   assert(n->Opcode() == Op_StoreCM, "expected StoreCM");
2192   if (n->in(MemNode::Address)->outcnt() > 1) {
2193     // There are multiple users of the same address so it might be
2194     // possible to eliminate some of the StoreCMs
2195     Node* mem = n->in(MemNode::Memory);
2196     Node* adr = n->in(MemNode::Address);
2197     Node* val = n->in(MemNode::ValueIn);
2198     Node* prev = n;
2199     bool done = false;
2200     // Walk the chain of StoreCMs eliminating ones that match.  As
2201     // long as it's a chain of single users then the optimization is
2202     // safe.  Eliminating partially redundant StoreCMs would require
2203     // cloning copies down the other paths.
2204     while (mem->Opcode() == Op_StoreCM && mem->outcnt() == 1 && !done) {
2205       if (adr == mem->in(MemNode::Address) &&
2206           val == mem->in(MemNode::ValueIn)) {
2207         // redundant StoreCM
2208         if (mem->req() > MemNode::OopStore) {
2209           // Hasn't been processed by this code yet.
2210           n->add_prec(mem->in(MemNode::OopStore));
2211         } else {
2212           // Already converted to precedence edge
2213           for (uint i = mem->req(); i < mem->len(); i++) {
2214             // Accumulate any precedence edges
2215             if (mem->in(i) != NULL) {
2216               n->add_prec(mem->in(i));
2217             }
2218           }
2219           // Everything above this point has been processed.
2220           done = true;
2221         }
2222         // Eliminate the previous StoreCM
2223         prev->set_req(MemNode::Memory, mem->in(MemNode::Memory));
2224         assert(mem->outcnt() == 0, "should be dead");
2225         mem->disconnect_inputs(NULL, this);
2226       } else {
2227         prev = mem;
2228       }
2229       mem = prev->in(MemNode::Memory);
2230     }
2231   }
2232 }
2233 
2234 //------------------------------final_graph_reshaping_impl----------------------
2235 // Implement items 1-5 from final_graph_reshaping below.
2236 void Compile::final_graph_reshaping_impl( Node *n, Final_Reshape_Counts &frc) {
2237 
2238   if ( n->outcnt() == 0 ) return; // dead node
2239   uint nop = n->Opcode();
2240 
2241   // Check for 2-input instruction with "last use" on right input.
2242   // Swap to left input.  Implements item (2).
2243   if( n->req() == 3 &&          // two-input instruction
2244       n->in(1)->outcnt() > 1 && // left use is NOT a last use
2245       (!n->in(1)->is_Phi() || n->in(1)->in(2) != n) && // it is not data loop
2246       n->in(2)->outcnt() == 1 &&// right use IS a last use
2247       !n->in(2)->is_Con() ) {   // right use is not a constant
2248     // Check for commutative opcode
2249     switch( nop ) {
2250     case Op_AddI:  case Op_AddF:  case Op_AddD:  case Op_AddL:
2251     case Op_MaxI:  case Op_MinI:
2252     case Op_MulI:  case Op_MulF:  case Op_MulD:  case Op_MulL:
2253     case Op_AndL:  case Op_XorL:  case Op_OrL:
2254     case Op_AndI:  case Op_XorI:  case Op_OrI: {
2255       // Move "last use" input to left by swapping inputs
2256       n->swap_edges(1, 2);
2257       break;
2258     }
2259     default:
2260       break;
2261     }
2262   }
2263 
2264 #ifdef ASSERT
2265   if( n->is_Mem() ) {
2266     int alias_idx = get_alias_index(n->as_Mem()->adr_type());
2267     assert( n->in(0) != NULL || alias_idx != Compile::AliasIdxRaw ||
2268             // oop will be recorded in oop map if load crosses safepoint
2269             n->is_Load() && (n->as_Load()->bottom_type()->isa_oopptr() ||
2270                              LoadNode::is_immutable_value(n->in(MemNode::Address))),
2271             "raw memory operations should have control edge");
2272   }
2273 #endif
2274   // Count FPU ops and common calls, implements item (3)
2275   switch( nop ) {
2276   // Count all float operations that may use FPU
2277   case Op_AddF:
2278   case Op_SubF:
2279   case Op_MulF:
2280   case Op_DivF:
2281   case Op_NegF:
2282   case Op_ModF:
2283   case Op_ConvI2F:
2284   case Op_ConF:
2285   case Op_CmpF:
2286   case Op_CmpF3:
2287   // case Op_ConvL2F: // longs are split into 32-bit halves
2288     frc.inc_float_count();
2289     break;
2290 
2291   case Op_ConvF2D:
2292   case Op_ConvD2F:
2293     frc.inc_float_count();
2294     frc.inc_double_count();
2295     break;
2296 
2297   // Count all double operations that may use FPU
2298   case Op_AddD:
2299   case Op_SubD:
2300   case Op_MulD:
2301   case Op_DivD:
2302   case Op_NegD:
2303   case Op_ModD:
2304   case Op_ConvI2D:
2305   case Op_ConvD2I:
2306   // case Op_ConvL2D: // handled by leaf call
2307   // case Op_ConvD2L: // handled by leaf call
2308   case Op_ConD:
2309   case Op_CmpD:
2310   case Op_CmpD3:
2311     frc.inc_double_count();
2312     break;
2313   case Op_Opaque1:              // Remove Opaque Nodes before matching
2314   case Op_Opaque2:              // Remove Opaque Nodes before matching
2315     n->subsume_by(n->in(1), this);
2316     break;
2317   case Op_CallStaticJava:
2318   case Op_CallJava:
2319   case Op_CallDynamicJava:
2320     frc.inc_java_call_count(); // Count java call site;
2321   case Op_CallRuntime:
2322   case Op_CallLeaf:
2323   case Op_CallLeafNoFP: {
2324     assert( n->is_Call(), "" );
2325     CallNode *call = n->as_Call();
2326     // Count call sites where the FP mode bit would have to be flipped.
2327     // Do not count uncommon runtime calls:
2328     // uncommon_trap, _complete_monitor_locking, _complete_monitor_unlocking,
2329     // _new_Java, _new_typeArray, _new_objArray, _rethrow_Java, ...
2330     if( !call->is_CallStaticJava() || !call->as_CallStaticJava()->_name ) {
2331       frc.inc_call_count();   // Count the call site
2332     } else {                  // See if uncommon argument is shared
2333       Node *n = call->in(TypeFunc::Parms);
2334       int nop = n->Opcode();
2335       // Clone shared simple arguments to uncommon calls, item (1).
2336       if( n->outcnt() > 1 &&
2337           !n->is_Proj() &&
2338           nop != Op_CreateEx &&
2339           nop != Op_CheckCastPP &&
2340           nop != Op_DecodeN &&
2341           nop != Op_DecodeNKlass &&
2342           !n->is_Mem() ) {
2343         Node *x = n->clone();
2344         call->set_req( TypeFunc::Parms, x );
2345       }
2346     }
2347     break;
2348   }
2349 
2350   case Op_StoreD:
2351   case Op_LoadD:
2352   case Op_LoadD_unaligned:
2353     frc.inc_double_count();
2354     goto handle_mem;
2355   case Op_StoreF:
2356   case Op_LoadF:
2357     frc.inc_float_count();
2358     goto handle_mem;
2359 
2360   case Op_StoreCM:
2361     {
2362       // Convert OopStore dependence into precedence edge
2363       Node* prec = n->in(MemNode::OopStore);
2364       n->del_req(MemNode::OopStore);
2365       n->add_prec(prec);
2366       eliminate_redundant_card_marks(n);
2367     }
2368 
2369     // fall through
2370 
2371   case Op_StoreB:
2372   case Op_StoreC:
2373   case Op_StorePConditional:
2374   case Op_StoreI:
2375   case Op_StoreL:
2376   case Op_StoreIConditional:
2377   case Op_StoreLConditional:
2378   case Op_CompareAndSwapI:
2379   case Op_CompareAndSwapL:
2380   case Op_CompareAndSwapP:
2381   case Op_CompareAndSwapN:
2382   case Op_GetAndAddI:
2383   case Op_GetAndAddL:
2384   case Op_GetAndSetI:
2385   case Op_GetAndSetL:
2386   case Op_GetAndSetP:
2387   case Op_GetAndSetN:
2388   case Op_StoreP:
2389   case Op_StoreN:
2390   case Op_StoreNKlass:
2391   case Op_LoadB:
2392   case Op_LoadUB:
2393   case Op_LoadUS:
2394   case Op_LoadI:
2395   case Op_LoadKlass:
2396   case Op_LoadNKlass:
2397   case Op_LoadL:
2398   case Op_LoadL_unaligned:
2399   case Op_LoadPLocked:
2400   case Op_LoadP:
2401   case Op_LoadN:
2402   case Op_LoadRange:
2403   case Op_LoadS: {
2404   handle_mem:
2405 #ifdef ASSERT
2406     if( VerifyOptoOopOffsets ) {
2407       assert( n->is_Mem(), "" );
2408       MemNode *mem  = (MemNode*)n;
2409       // Check to see if address types have grounded out somehow.
2410       const TypeInstPtr *tp = mem->in(MemNode::Address)->bottom_type()->isa_instptr();
2411       assert( !tp || oop_offset_is_sane(tp), "" );
2412     }
2413 #endif
2414     break;
2415   }
2416 
2417   case Op_AddP: {               // Assert sane base pointers
2418     Node *addp = n->in(AddPNode::Address);
2419     assert( !addp->is_AddP() ||
2420             addp->in(AddPNode::Base)->is_top() || // Top OK for allocation
2421             addp->in(AddPNode::Base) == n->in(AddPNode::Base),
2422             "Base pointers must match" );
2423 #ifdef _LP64
2424     if ((UseCompressedOops || UseCompressedKlassPointers) &&
2425         addp->Opcode() == Op_ConP &&
2426         addp == n->in(AddPNode::Base) &&
2427         n->in(AddPNode::Offset)->is_Con()) {
2428       // Use addressing with narrow klass to load with offset on x86.
2429       // On sparc loading 32-bits constant and decoding it have less
2430       // instructions (4) then load 64-bits constant (7).
2431       // Do this transformation here since IGVN will convert ConN back to ConP.
2432       const Type* t = addp->bottom_type();
2433       if (t->isa_oopptr() || t->isa_klassptr()) {
2434         Node* nn = NULL;
2435 
2436         int op = t->isa_oopptr() ? Op_ConN : Op_ConNKlass;
2437 
2438         // Look for existing ConN node of the same exact type.
2439         Node* r  = root();
2440         uint cnt = r->outcnt();
2441         for (uint i = 0; i < cnt; i++) {
2442           Node* m = r->raw_out(i);
2443           if (m!= NULL && m->Opcode() == op &&
2444               m->bottom_type()->make_ptr() == t) {
2445             nn = m;
2446             break;
2447           }
2448         }
2449         if (nn != NULL) {
2450           // Decode a narrow oop to match address
2451           // [R12 + narrow_oop_reg<<3 + offset]
2452           if (t->isa_oopptr()) {
2453             nn = new (this) DecodeNNode(nn, t);
2454           } else {
2455             nn = new (this) DecodeNKlassNode(nn, t);
2456           }
2457           n->set_req(AddPNode::Base, nn);
2458           n->set_req(AddPNode::Address, nn);
2459           if (addp->outcnt() == 0) {
2460             addp->disconnect_inputs(NULL, this);
2461           }
2462         }
2463       }
2464     }
2465 #endif
2466     break;
2467   }
2468 
2469 #ifdef _LP64
2470   case Op_CastPP:
2471     if (n->in(1)->is_DecodeN() && Matcher::gen_narrow_oop_implicit_null_checks()) {
2472       Node* in1 = n->in(1);
2473       const Type* t = n->bottom_type();
2474       Node* new_in1 = in1->clone();
2475       new_in1->as_DecodeN()->set_type(t);
2476 
2477       if (!Matcher::narrow_oop_use_complex_address()) {
2478         //
2479         // x86, ARM and friends can handle 2 adds in addressing mode
2480         // and Matcher can fold a DecodeN node into address by using
2481         // a narrow oop directly and do implicit NULL check in address:
2482         //
2483         // [R12 + narrow_oop_reg<<3 + offset]
2484         // NullCheck narrow_oop_reg
2485         //
2486         // On other platforms (Sparc) we have to keep new DecodeN node and
2487         // use it to do implicit NULL check in address:
2488         //
2489         // decode_not_null narrow_oop_reg, base_reg
2490         // [base_reg + offset]
2491         // NullCheck base_reg
2492         //
2493         // Pin the new DecodeN node to non-null path on these platform (Sparc)
2494         // to keep the information to which NULL check the new DecodeN node
2495         // corresponds to use it as value in implicit_null_check().
2496         //
2497         new_in1->set_req(0, n->in(0));
2498       }
2499 
2500       n->subsume_by(new_in1, this);
2501       if (in1->outcnt() == 0) {
2502         in1->disconnect_inputs(NULL, this);
2503       }
2504     }
2505     break;
2506 
2507   case Op_CmpP:
2508     // Do this transformation here to preserve CmpPNode::sub() and
2509     // other TypePtr related Ideal optimizations (for example, ptr nullness).
2510     if (n->in(1)->is_DecodeNarrowPtr() || n->in(2)->is_DecodeNarrowPtr()) {
2511       Node* in1 = n->in(1);
2512       Node* in2 = n->in(2);
2513       if (!in1->is_DecodeNarrowPtr()) {
2514         in2 = in1;
2515         in1 = n->in(2);
2516       }
2517       assert(in1->is_DecodeNarrowPtr(), "sanity");
2518 
2519       Node* new_in2 = NULL;
2520       if (in2->is_DecodeNarrowPtr()) {
2521         assert(in2->Opcode() == in1->Opcode(), "must be same node type");
2522         new_in2 = in2->in(1);
2523       } else if (in2->Opcode() == Op_ConP) {
2524         const Type* t = in2->bottom_type();
2525         if (t == TypePtr::NULL_PTR) {
2526           assert(in1->is_DecodeN(), "compare klass to null?");
2527           // Don't convert CmpP null check into CmpN if compressed
2528           // oops implicit null check is not generated.
2529           // This will allow to generate normal oop implicit null check.
2530           if (Matcher::gen_narrow_oop_implicit_null_checks())
2531             new_in2 = ConNode::make(this, TypeNarrowOop::NULL_PTR);
2532           //
2533           // This transformation together with CastPP transformation above
2534           // will generated code for implicit NULL checks for compressed oops.
2535           //
2536           // The original code after Optimize()
2537           //
2538           //    LoadN memory, narrow_oop_reg
2539           //    decode narrow_oop_reg, base_reg
2540           //    CmpP base_reg, NULL
2541           //    CastPP base_reg // NotNull
2542           //    Load [base_reg + offset], val_reg
2543           //
2544           // after these transformations will be
2545           //
2546           //    LoadN memory, narrow_oop_reg
2547           //    CmpN narrow_oop_reg, NULL
2548           //    decode_not_null narrow_oop_reg, base_reg
2549           //    Load [base_reg + offset], val_reg
2550           //
2551           // and the uncommon path (== NULL) will use narrow_oop_reg directly
2552           // since narrow oops can be used in debug info now (see the code in
2553           // final_graph_reshaping_walk()).
2554           //
2555           // At the end the code will be matched to
2556           // on x86:
2557           //
2558           //    Load_narrow_oop memory, narrow_oop_reg
2559           //    Load [R12 + narrow_oop_reg<<3 + offset], val_reg
2560           //    NullCheck narrow_oop_reg
2561           //
2562           // and on sparc:
2563           //
2564           //    Load_narrow_oop memory, narrow_oop_reg
2565           //    decode_not_null narrow_oop_reg, base_reg
2566           //    Load [base_reg + offset], val_reg
2567           //    NullCheck base_reg
2568           //
2569         } else if (t->isa_oopptr()) {
2570           new_in2 = ConNode::make(this, t->make_narrowoop());
2571         } else if (t->isa_klassptr()) {
2572           new_in2 = ConNode::make(this, t->make_narrowklass());
2573         }
2574       }
2575       if (new_in2 != NULL) {
2576         Node* cmpN = new (this) CmpNNode(in1->in(1), new_in2);
2577         n->subsume_by(cmpN, this);
2578         if (in1->outcnt() == 0) {
2579           in1->disconnect_inputs(NULL, this);
2580         }
2581         if (in2->outcnt() == 0) {
2582           in2->disconnect_inputs(NULL, this);
2583         }
2584       }
2585     }
2586     break;
2587 
2588   case Op_DecodeN:
2589   case Op_DecodeNKlass:
2590     assert(!n->in(1)->is_EncodeNarrowPtr(), "should be optimized out");
2591     // DecodeN could be pinned when it can't be fold into
2592     // an address expression, see the code for Op_CastPP above.
2593     assert(n->in(0) == NULL || (UseCompressedOops && !Matcher::narrow_oop_use_complex_address()), "no control");
2594     break;
2595 
2596   case Op_EncodeP:
2597   case Op_EncodePKlass: {
2598     Node* in1 = n->in(1);
2599     if (in1->is_DecodeNarrowPtr()) {
2600       n->subsume_by(in1->in(1), this);
2601     } else if (in1->Opcode() == Op_ConP) {
2602       const Type* t = in1->bottom_type();
2603       if (t == TypePtr::NULL_PTR) {
2604         assert(t->isa_oopptr(), "null klass?");
2605         n->subsume_by(ConNode::make(this, TypeNarrowOop::NULL_PTR), this);
2606       } else if (t->isa_oopptr()) {
2607         n->subsume_by(ConNode::make(this, t->make_narrowoop()), this);
2608       } else if (t->isa_klassptr()) {
2609         n->subsume_by(ConNode::make(this, t->make_narrowklass()), this);
2610       }
2611     }
2612     if (in1->outcnt() == 0) {
2613       in1->disconnect_inputs(NULL, this);
2614     }
2615     break;
2616   }
2617 
2618   case Op_Proj: {
2619     if (OptimizeStringConcat) {
2620       ProjNode* p = n->as_Proj();
2621       if (p->_is_io_use) {
2622         // Separate projections were used for the exception path which
2623         // are normally removed by a late inline.  If it wasn't inlined
2624         // then they will hang around and should just be replaced with
2625         // the original one.
2626         Node* proj = NULL;
2627         // Replace with just one
2628         for (SimpleDUIterator i(p->in(0)); i.has_next(); i.next()) {
2629           Node *use = i.get();
2630           if (use->is_Proj() && p != use && use->as_Proj()->_con == p->_con) {
2631             proj = use;
2632             break;
2633           }
2634         }
2635         assert(proj != NULL, "must be found");
2636         p->subsume_by(proj, this);
2637       }
2638     }
2639     break;
2640   }
2641 
2642   case Op_Phi:
2643     if (n->as_Phi()->bottom_type()->isa_narrowoop() || n->as_Phi()->bottom_type()->isa_narrowklass()) {
2644       // The EncodeP optimization may create Phi with the same edges
2645       // for all paths. It is not handled well by Register Allocator.
2646       Node* unique_in = n->in(1);
2647       assert(unique_in != NULL, "");
2648       uint cnt = n->req();
2649       for (uint i = 2; i < cnt; i++) {
2650         Node* m = n->in(i);
2651         assert(m != NULL, "");
2652         if (unique_in != m)
2653           unique_in = NULL;
2654       }
2655       if (unique_in != NULL) {
2656         n->subsume_by(unique_in, this);
2657       }
2658     }
2659     break;
2660 
2661 #endif
2662 
2663   case Op_ModI:
2664     if (UseDivMod) {
2665       // Check if a%b and a/b both exist
2666       Node* d = n->find_similar(Op_DivI);
2667       if (d) {
2668         // Replace them with a fused divmod if supported
2669         if (Matcher::has_match_rule(Op_DivModI)) {
2670           DivModINode* divmod = DivModINode::make(this, n);
2671           d->subsume_by(divmod->div_proj(), this);
2672           n->subsume_by(divmod->mod_proj(), this);
2673         } else {
2674           // replace a%b with a-((a/b)*b)
2675           Node* mult = new (this) MulINode(d, d->in(2));
2676           Node* sub  = new (this) SubINode(d->in(1), mult);
2677           n->subsume_by(sub, this);
2678         }
2679       }
2680     }
2681     break;
2682 
2683   case Op_ModL:
2684     if (UseDivMod) {
2685       // Check if a%b and a/b both exist
2686       Node* d = n->find_similar(Op_DivL);
2687       if (d) {
2688         // Replace them with a fused divmod if supported
2689         if (Matcher::has_match_rule(Op_DivModL)) {
2690           DivModLNode* divmod = DivModLNode::make(this, n);
2691           d->subsume_by(divmod->div_proj(), this);
2692           n->subsume_by(divmod->mod_proj(), this);
2693         } else {
2694           // replace a%b with a-((a/b)*b)
2695           Node* mult = new (this) MulLNode(d, d->in(2));
2696           Node* sub  = new (this) SubLNode(d->in(1), mult);
2697           n->subsume_by(sub, this);
2698         }
2699       }
2700     }
2701     break;
2702 
2703   case Op_LoadVector:
2704   case Op_StoreVector:
2705     break;
2706 
2707   case Op_PackB:
2708   case Op_PackS:
2709   case Op_PackI:
2710   case Op_PackF:
2711   case Op_PackL:
2712   case Op_PackD:
2713     if (n->req()-1 > 2) {
2714       // Replace many operand PackNodes with a binary tree for matching
2715       PackNode* p = (PackNode*) n;
2716       Node* btp = p->binary_tree_pack(this, 1, n->req());
2717       n->subsume_by(btp, this);
2718     }
2719     break;
2720   case Op_Loop:
2721   case Op_CountedLoop:
2722     if (n->as_Loop()->is_inner_loop()) {
2723       frc.inc_inner_loop_count();
2724     }
2725     break;
2726   case Op_LShiftI:
2727   case Op_RShiftI:
2728   case Op_URShiftI:
2729   case Op_LShiftL:
2730   case Op_RShiftL:
2731   case Op_URShiftL:
2732     if (Matcher::need_masked_shift_count) {
2733       // The cpu's shift instructions don't restrict the count to the
2734       // lower 5/6 bits. We need to do the masking ourselves.
2735       Node* in2 = n->in(2);
2736       juint mask = (n->bottom_type() == TypeInt::INT) ? (BitsPerInt - 1) : (BitsPerLong - 1);
2737       const TypeInt* t = in2->find_int_type();
2738       if (t != NULL && t->is_con()) {
2739         juint shift = t->get_con();
2740         if (shift > mask) { // Unsigned cmp
2741           n->set_req(2, ConNode::make(this, TypeInt::make(shift & mask)));
2742         }
2743       } else {
2744         if (t == NULL || t->_lo < 0 || t->_hi > (int)mask) {
2745           Node* shift = new (this) AndINode(in2, ConNode::make(this, TypeInt::make(mask)));
2746           n->set_req(2, shift);
2747         }
2748       }
2749       if (in2->outcnt() == 0) { // Remove dead node
2750         in2->disconnect_inputs(NULL, this);
2751       }
2752     }
2753     break;
2754   default:
2755     assert( !n->is_Call(), "" );
2756     assert( !n->is_Mem(), "" );
2757     break;
2758   }
2759 
2760   // Collect CFG split points
2761   if (n->is_MultiBranch())
2762     frc._tests.push(n);
2763 }
2764 
2765 //------------------------------final_graph_reshaping_walk---------------------
2766 // Replacing Opaque nodes with their input in final_graph_reshaping_impl(),
2767 // requires that the walk visits a node's inputs before visiting the node.
2768 void Compile::final_graph_reshaping_walk( Node_Stack &nstack, Node *root, Final_Reshape_Counts &frc ) {
2769   ResourceArea *area = Thread::current()->resource_area();
2770   Unique_Node_List sfpt(area);
2771 
2772   frc._visited.set(root->_idx); // first, mark node as visited
2773   uint cnt = root->req();
2774   Node *n = root;
2775   uint  i = 0;
2776   while (true) {
2777     if (i < cnt) {
2778       // Place all non-visited non-null inputs onto stack
2779       Node* m = n->in(i);
2780       ++i;
2781       if (m != NULL && !frc._visited.test_set(m->_idx)) {
2782         if (m->is_SafePoint() && m->as_SafePoint()->jvms() != NULL)
2783           sfpt.push(m);
2784         cnt = m->req();
2785         nstack.push(n, i); // put on stack parent and next input's index
2786         n = m;
2787         i = 0;
2788       }
2789     } else {
2790       // Now do post-visit work
2791       final_graph_reshaping_impl( n, frc );
2792       if (nstack.is_empty())
2793         break;             // finished
2794       n = nstack.node();   // Get node from stack
2795       cnt = n->req();
2796       i = nstack.index();
2797       nstack.pop();        // Shift to the next node on stack
2798     }
2799   }
2800 
2801   // Skip next transformation if compressed oops are not used.
2802   if ((UseCompressedOops && !Matcher::gen_narrow_oop_implicit_null_checks()) ||
2803       (!UseCompressedOops && !UseCompressedKlassPointers))
2804     return;
2805 
2806   // Go over safepoints nodes to skip DecodeN/DecodeNKlass nodes for debug edges.
2807   // It could be done for an uncommon traps or any safepoints/calls
2808   // if the DecodeN/DecodeNKlass node is referenced only in a debug info.
2809   while (sfpt.size() > 0) {
2810     n = sfpt.pop();
2811     JVMState *jvms = n->as_SafePoint()->jvms();
2812     assert(jvms != NULL, "sanity");
2813     int start = jvms->debug_start();
2814     int end   = n->req();
2815     bool is_uncommon = (n->is_CallStaticJava() &&
2816                         n->as_CallStaticJava()->uncommon_trap_request() != 0);
2817     for (int j = start; j < end; j++) {
2818       Node* in = n->in(j);
2819       if (in->is_DecodeNarrowPtr()) {
2820         bool safe_to_skip = true;
2821         if (!is_uncommon ) {
2822           // Is it safe to skip?
2823           for (uint i = 0; i < in->outcnt(); i++) {
2824             Node* u = in->raw_out(i);
2825             if (!u->is_SafePoint() ||
2826                  u->is_Call() && u->as_Call()->has_non_debug_use(n)) {
2827               safe_to_skip = false;
2828             }
2829           }
2830         }
2831         if (safe_to_skip) {
2832           n->set_req(j, in->in(1));
2833         }
2834         if (in->outcnt() == 0) {
2835           in->disconnect_inputs(NULL, this);
2836         }
2837       }
2838     }
2839   }
2840 }
2841 
2842 //------------------------------final_graph_reshaping--------------------------
2843 // Final Graph Reshaping.
2844 //
2845 // (1) Clone simple inputs to uncommon calls, so they can be scheduled late
2846 //     and not commoned up and forced early.  Must come after regular
2847 //     optimizations to avoid GVN undoing the cloning.  Clone constant
2848 //     inputs to Loop Phis; these will be split by the allocator anyways.
2849 //     Remove Opaque nodes.
2850 // (2) Move last-uses by commutative operations to the left input to encourage
2851 //     Intel update-in-place two-address operations and better register usage
2852 //     on RISCs.  Must come after regular optimizations to avoid GVN Ideal
2853 //     calls canonicalizing them back.
2854 // (3) Count the number of double-precision FP ops, single-precision FP ops
2855 //     and call sites.  On Intel, we can get correct rounding either by
2856 //     forcing singles to memory (requires extra stores and loads after each
2857 //     FP bytecode) or we can set a rounding mode bit (requires setting and
2858 //     clearing the mode bit around call sites).  The mode bit is only used
2859 //     if the relative frequency of single FP ops to calls is low enough.
2860 //     This is a key transform for SPEC mpeg_audio.
2861 // (4) Detect infinite loops; blobs of code reachable from above but not
2862 //     below.  Several of the Code_Gen algorithms fail on such code shapes,
2863 //     so we simply bail out.  Happens a lot in ZKM.jar, but also happens
2864 //     from time to time in other codes (such as -Xcomp finalizer loops, etc).
2865 //     Detection is by looking for IfNodes where only 1 projection is
2866 //     reachable from below or CatchNodes missing some targets.
2867 // (5) Assert for insane oop offsets in debug mode.
2868 
2869 bool Compile::final_graph_reshaping() {
2870   // an infinite loop may have been eliminated by the optimizer,
2871   // in which case the graph will be empty.
2872   if (root()->req() == 1) {
2873     record_method_not_compilable("trivial infinite loop");
2874     return true;
2875   }
2876 
2877   Final_Reshape_Counts frc;
2878 
2879   // Visit everybody reachable!
2880   // Allocate stack of size C->unique()/2 to avoid frequent realloc
2881   Node_Stack nstack(unique() >> 1);
2882   final_graph_reshaping_walk(nstack, root(), frc);
2883 
2884   // Check for unreachable (from below) code (i.e., infinite loops).
2885   for( uint i = 0; i < frc._tests.size(); i++ ) {
2886     MultiBranchNode *n = frc._tests[i]->as_MultiBranch();
2887     // Get number of CFG targets.
2888     // Note that PCTables include exception targets after calls.
2889     uint required_outcnt = n->required_outcnt();
2890     if (n->outcnt() != required_outcnt) {
2891       // Check for a few special cases.  Rethrow Nodes never take the
2892       // 'fall-thru' path, so expected kids is 1 less.
2893       if (n->is_PCTable() && n->in(0) && n->in(0)->in(0)) {
2894         if (n->in(0)->in(0)->is_Call()) {
2895           CallNode *call = n->in(0)->in(0)->as_Call();
2896           if (call->entry_point() == OptoRuntime::rethrow_stub()) {
2897             required_outcnt--;      // Rethrow always has 1 less kid
2898           } else if (call->req() > TypeFunc::Parms &&
2899                      call->is_CallDynamicJava()) {
2900             // Check for null receiver. In such case, the optimizer has
2901             // detected that the virtual call will always result in a null
2902             // pointer exception. The fall-through projection of this CatchNode
2903             // will not be populated.
2904             Node *arg0 = call->in(TypeFunc::Parms);
2905             if (arg0->is_Type() &&
2906                 arg0->as_Type()->type()->higher_equal(TypePtr::NULL_PTR)) {
2907               required_outcnt--;
2908             }
2909           } else if (call->entry_point() == OptoRuntime::new_array_Java() &&
2910                      call->req() > TypeFunc::Parms+1 &&
2911                      call->is_CallStaticJava()) {
2912             // Check for negative array length. In such case, the optimizer has
2913             // detected that the allocation attempt will always result in an
2914             // exception. There is no fall-through projection of this CatchNode .
2915             Node *arg1 = call->in(TypeFunc::Parms+1);
2916             if (arg1->is_Type() &&
2917                 arg1->as_Type()->type()->join(TypeInt::POS)->empty()) {
2918               required_outcnt--;
2919             }
2920           }
2921         }
2922       }
2923       // Recheck with a better notion of 'required_outcnt'
2924       if (n->outcnt() != required_outcnt) {
2925         record_method_not_compilable("malformed control flow");
2926         return true;            // Not all targets reachable!
2927       }
2928     }
2929     // Check that I actually visited all kids.  Unreached kids
2930     // must be infinite loops.
2931     for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++)
2932       if (!frc._visited.test(n->fast_out(j)->_idx)) {
2933         record_method_not_compilable("infinite loop");
2934         return true;            // Found unvisited kid; must be unreach
2935       }
2936   }
2937 
2938   // If original bytecodes contained a mixture of floats and doubles
2939   // check if the optimizer has made it homogenous, item (3).
2940   if( Use24BitFPMode && Use24BitFP && UseSSE == 0 &&
2941       frc.get_float_count() > 32 &&
2942       frc.get_double_count() == 0 &&
2943       (10 * frc.get_call_count() < frc.get_float_count()) ) {
2944     set_24_bit_selection_and_mode( false,  true );
2945   }
2946 
2947   set_java_calls(frc.get_java_call_count());
2948   set_inner_loops(frc.get_inner_loop_count());
2949 
2950   // No infinite loops, no reason to bail out.
2951   return false;
2952 }
2953 
2954 //-----------------------------too_many_traps----------------------------------
2955 // Report if there are too many traps at the current method and bci.
2956 // Return true if there was a trap, and/or PerMethodTrapLimit is exceeded.
2957 bool Compile::too_many_traps(ciMethod* method,
2958                              int bci,
2959                              Deoptimization::DeoptReason reason) {
2960   ciMethodData* md = method->method_data();
2961   if (md->is_empty()) {
2962     // Assume the trap has not occurred, or that it occurred only
2963     // because of a transient condition during start-up in the interpreter.
2964     return false;
2965   }
2966   if (md->has_trap_at(bci, reason) != 0) {
2967     // Assume PerBytecodeTrapLimit==0, for a more conservative heuristic.
2968     // Also, if there are multiple reasons, or if there is no per-BCI record,
2969     // assume the worst.
2970     if (log())
2971       log()->elem("observe trap='%s' count='%d'",
2972                   Deoptimization::trap_reason_name(reason),
2973                   md->trap_count(reason));
2974     return true;
2975   } else {
2976     // Ignore method/bci and see if there have been too many globally.
2977     return too_many_traps(reason, md);
2978   }
2979 }
2980 
2981 // Less-accurate variant which does not require a method and bci.
2982 bool Compile::too_many_traps(Deoptimization::DeoptReason reason,
2983                              ciMethodData* logmd) {
2984  if (trap_count(reason) >= (uint)PerMethodTrapLimit) {
2985     // Too many traps globally.
2986     // Note that we use cumulative trap_count, not just md->trap_count.
2987     if (log()) {
2988       int mcount = (logmd == NULL)? -1: (int)logmd->trap_count(reason);
2989       log()->elem("observe trap='%s' count='0' mcount='%d' ccount='%d'",
2990                   Deoptimization::trap_reason_name(reason),
2991                   mcount, trap_count(reason));
2992     }
2993     return true;
2994   } else {
2995     // The coast is clear.
2996     return false;
2997   }
2998 }
2999 
3000 //--------------------------too_many_recompiles--------------------------------
3001 // Report if there are too many recompiles at the current method and bci.
3002 // Consults PerBytecodeRecompilationCutoff and PerMethodRecompilationCutoff.
3003 // Is not eager to return true, since this will cause the compiler to use
3004 // Action_none for a trap point, to avoid too many recompilations.
3005 bool Compile::too_many_recompiles(ciMethod* method,
3006                                   int bci,
3007                                   Deoptimization::DeoptReason reason) {
3008   ciMethodData* md = method->method_data();
3009   if (md->is_empty()) {
3010     // Assume the trap has not occurred, or that it occurred only
3011     // because of a transient condition during start-up in the interpreter.
3012     return false;
3013   }
3014   // Pick a cutoff point well within PerBytecodeRecompilationCutoff.
3015   uint bc_cutoff = (uint) PerBytecodeRecompilationCutoff / 8;
3016   uint m_cutoff  = (uint) PerMethodRecompilationCutoff / 2 + 1;  // not zero
3017   Deoptimization::DeoptReason per_bc_reason
3018     = Deoptimization::reason_recorded_per_bytecode_if_any(reason);
3019   if ((per_bc_reason == Deoptimization::Reason_none
3020        || md->has_trap_at(bci, reason) != 0)
3021       // The trap frequency measure we care about is the recompile count:
3022       && md->trap_recompiled_at(bci)
3023       && md->overflow_recompile_count() >= bc_cutoff) {
3024     // Do not emit a trap here if it has already caused recompilations.
3025     // Also, if there are multiple reasons, or if there is no per-BCI record,
3026     // assume the worst.
3027     if (log())
3028       log()->elem("observe trap='%s recompiled' count='%d' recompiles2='%d'",
3029                   Deoptimization::trap_reason_name(reason),
3030                   md->trap_count(reason),
3031                   md->overflow_recompile_count());
3032     return true;
3033   } else if (trap_count(reason) != 0
3034              && decompile_count() >= m_cutoff) {
3035     // Too many recompiles globally, and we have seen this sort of trap.
3036     // Use cumulative decompile_count, not just md->decompile_count.
3037     if (log())
3038       log()->elem("observe trap='%s' count='%d' mcount='%d' decompiles='%d' mdecompiles='%d'",
3039                   Deoptimization::trap_reason_name(reason),
3040                   md->trap_count(reason), trap_count(reason),
3041                   md->decompile_count(), decompile_count());
3042     return true;
3043   } else {
3044     // The coast is clear.
3045     return false;
3046   }
3047 }
3048 
3049 
3050 #ifndef PRODUCT
3051 //------------------------------verify_graph_edges---------------------------
3052 // Walk the Graph and verify that there is a one-to-one correspondence
3053 // between Use-Def edges and Def-Use edges in the graph.
3054 void Compile::verify_graph_edges(bool no_dead_code) {
3055   if (VerifyGraphEdges) {
3056     ResourceArea *area = Thread::current()->resource_area();
3057     Unique_Node_List visited(area);
3058     // Call recursive graph walk to check edges
3059     _root->verify_edges(visited);
3060     if (no_dead_code) {
3061       // Now make sure that no visited node is used by an unvisited node.
3062       bool dead_nodes = 0;
3063       Unique_Node_List checked(area);
3064       while (visited.size() > 0) {
3065         Node* n = visited.pop();
3066         checked.push(n);
3067         for (uint i = 0; i < n->outcnt(); i++) {
3068           Node* use = n->raw_out(i);
3069           if (checked.member(use))  continue;  // already checked
3070           if (visited.member(use))  continue;  // already in the graph
3071           if (use->is_Con())        continue;  // a dead ConNode is OK
3072           // At this point, we have found a dead node which is DU-reachable.
3073           if (dead_nodes++ == 0)
3074             tty->print_cr("*** Dead nodes reachable via DU edges:");
3075           use->dump(2);
3076           tty->print_cr("---");
3077           checked.push(use);  // No repeats; pretend it is now checked.
3078         }
3079       }
3080       assert(dead_nodes == 0, "using nodes must be reachable from root");
3081     }
3082   }
3083 }
3084 #endif
3085 
3086 // The Compile object keeps track of failure reasons separately from the ciEnv.
3087 // This is required because there is not quite a 1-1 relation between the
3088 // ciEnv and its compilation task and the Compile object.  Note that one
3089 // ciEnv might use two Compile objects, if C2Compiler::compile_method decides
3090 // to backtrack and retry without subsuming loads.  Other than this backtracking
3091 // behavior, the Compile's failure reason is quietly copied up to the ciEnv
3092 // by the logic in C2Compiler.
3093 void Compile::record_failure(const char* reason) {
3094   if (log() != NULL) {
3095     log()->elem("failure reason='%s' phase='compile'", reason);
3096   }
3097   if (_failure_reason == NULL) {
3098     // Record the first failure reason.
3099     _failure_reason = reason;
3100   }
3101   if (!C->failure_reason_is(C2Compiler::retry_no_subsuming_loads())) {
3102     C->print_method(_failure_reason);
3103   }
3104   _root = NULL;  // flush the graph, too
3105 }
3106 
3107 Compile::TracePhase::TracePhase(const char* name, elapsedTimer* accumulator, bool dolog)
3108   : TraceTime(NULL, accumulator, false NOT_PRODUCT( || TimeCompiler ), false),
3109     _phase_name(name), _dolog(dolog)
3110 {
3111   if (dolog) {
3112     C = Compile::current();
3113     _log = C->log();
3114   } else {
3115     C = NULL;
3116     _log = NULL;
3117   }
3118   if (_log != NULL) {
3119     _log->begin_head("phase name='%s' nodes='%d' live='%d'", _phase_name, C->unique(), C->live_nodes());
3120     _log->stamp();
3121     _log->end_head();
3122   }
3123 }
3124 
3125 Compile::TracePhase::~TracePhase() {
3126 
3127   C = Compile::current();
3128   if (_dolog) {
3129     _log = C->log();
3130   } else {
3131     _log = NULL;
3132   }
3133 
3134 #ifdef ASSERT
3135   if (PrintIdealNodeCount) {
3136     tty->print_cr("phase name='%s' nodes='%d' live='%d' live_graph_walk='%d'",
3137                   _phase_name, C->unique(), C->live_nodes(), C->count_live_nodes_by_graph_walk());
3138   }
3139 
3140   if (VerifyIdealNodeCount) {
3141     Compile::current()->print_missing_nodes();
3142   }
3143 #endif
3144 
3145   if (_log != NULL) {
3146     _log->done("phase name='%s' nodes='%d' live='%d'", _phase_name, C->unique(), C->live_nodes());
3147   }
3148 }
3149 
3150 //=============================================================================
3151 // Two Constant's are equal when the type and the value are equal.
3152 bool Compile::Constant::operator==(const Constant& other) {
3153   if (type()          != other.type()         )  return false;
3154   if (can_be_reused() != other.can_be_reused())  return false;
3155   // For floating point values we compare the bit pattern.
3156   switch (type()) {
3157   case T_FLOAT:   return (_v._value.i == other._v._value.i);
3158   case T_LONG:
3159   case T_DOUBLE:  return (_v._value.j == other._v._value.j);
3160   case T_OBJECT:
3161   case T_ADDRESS: return (_v._value.l == other._v._value.l);
3162   case T_VOID:    return (_v._value.l == other._v._value.l);  // jump-table entries
3163   case T_METADATA: return (_v._metadata == other._v._metadata);
3164   default: ShouldNotReachHere();
3165   }
3166   return false;
3167 }
3168 
3169 static int type_to_size_in_bytes(BasicType t) {
3170   switch (t) {
3171   case T_LONG:    return sizeof(jlong  );
3172   case T_FLOAT:   return sizeof(jfloat );
3173   case T_DOUBLE:  return sizeof(jdouble);
3174   case T_METADATA: return sizeof(Metadata*);
3175     // We use T_VOID as marker for jump-table entries (labels) which
3176     // need an internal word relocation.
3177   case T_VOID:
3178   case T_ADDRESS:
3179   case T_OBJECT:  return sizeof(jobject);
3180   }
3181 
3182   ShouldNotReachHere();
3183   return -1;
3184 }
3185 
3186 int Compile::ConstantTable::qsort_comparator(Constant* a, Constant* b) {
3187   // sort descending
3188   if (a->freq() > b->freq())  return -1;
3189   if (a->freq() < b->freq())  return  1;
3190   return 0;
3191 }
3192 
3193 void Compile::ConstantTable::calculate_offsets_and_size() {
3194   // First, sort the array by frequencies.
3195   _constants.sort(qsort_comparator);
3196 
3197 #ifdef ASSERT
3198   // Make sure all jump-table entries were sorted to the end of the
3199   // array (they have a negative frequency).
3200   bool found_void = false;
3201   for (int i = 0; i < _constants.length(); i++) {
3202     Constant con = _constants.at(i);
3203     if (con.type() == T_VOID)
3204       found_void = true;  // jump-tables
3205     else
3206       assert(!found_void, "wrong sorting");
3207   }
3208 #endif
3209 
3210   int offset = 0;
3211   for (int i = 0; i < _constants.length(); i++) {
3212     Constant* con = _constants.adr_at(i);
3213 
3214     // Align offset for type.
3215     int typesize = type_to_size_in_bytes(con->type());
3216     offset = align_size_up(offset, typesize);
3217     con->set_offset(offset);   // set constant's offset
3218 
3219     if (con->type() == T_VOID) {
3220       MachConstantNode* n = (MachConstantNode*) con->get_jobject();
3221       offset = offset + typesize * n->outcnt();  // expand jump-table
3222     } else {
3223       offset = offset + typesize;
3224     }
3225   }
3226 
3227   // Align size up to the next section start (which is insts; see
3228   // CodeBuffer::align_at_start).
3229   assert(_size == -1, "already set?");
3230   _size = align_size_up(offset, CodeEntryAlignment);
3231 }
3232 
3233 void Compile::ConstantTable::emit(CodeBuffer& cb) {
3234   MacroAssembler _masm(&cb);
3235   for (int i = 0; i < _constants.length(); i++) {
3236     Constant con = _constants.at(i);
3237     address constant_addr;
3238     switch (con.type()) {
3239     case T_LONG:   constant_addr = _masm.long_constant(  con.get_jlong()  ); break;
3240     case T_FLOAT:  constant_addr = _masm.float_constant( con.get_jfloat() ); break;
3241     case T_DOUBLE: constant_addr = _masm.double_constant(con.get_jdouble()); break;
3242     case T_OBJECT: {
3243       jobject obj = con.get_jobject();
3244       int oop_index = _masm.oop_recorder()->find_index(obj);
3245       constant_addr = _masm.address_constant((address) obj, oop_Relocation::spec(oop_index));
3246       break;
3247     }
3248     case T_ADDRESS: {
3249       address addr = (address) con.get_jobject();
3250       constant_addr = _masm.address_constant(addr);
3251       break;
3252     }
3253     // We use T_VOID as marker for jump-table entries (labels) which
3254     // need an internal word relocation.
3255     case T_VOID: {
3256       MachConstantNode* n = (MachConstantNode*) con.get_jobject();
3257       // Fill the jump-table with a dummy word.  The real value is
3258       // filled in later in fill_jump_table.
3259       address dummy = (address) n;
3260       constant_addr = _masm.address_constant(dummy);
3261       // Expand jump-table
3262       for (uint i = 1; i < n->outcnt(); i++) {
3263         address temp_addr = _masm.address_constant(dummy + i);
3264         assert(temp_addr, "consts section too small");
3265       }
3266       break;
3267     }
3268     case T_METADATA: {
3269       Metadata* obj = con.get_metadata();
3270       int metadata_index = _masm.oop_recorder()->find_index(obj);
3271       constant_addr = _masm.address_constant((address) obj, metadata_Relocation::spec(metadata_index));
3272       break;
3273     }
3274     default: ShouldNotReachHere();
3275     }
3276     assert(constant_addr, "consts section too small");
3277     assert((constant_addr - _masm.code()->consts()->start()) == con.offset(), err_msg_res("must be: %d == %d", constant_addr - _masm.code()->consts()->start(), con.offset()));
3278   }
3279 }
3280 
3281 int Compile::ConstantTable::find_offset(Constant& con) const {
3282   int idx = _constants.find(con);
3283   assert(idx != -1, "constant must be in constant table");
3284   int offset = _constants.at(idx).offset();
3285   assert(offset != -1, "constant table not emitted yet?");
3286   return offset;
3287 }
3288 
3289 void Compile::ConstantTable::add(Constant& con) {
3290   if (con.can_be_reused()) {
3291     int idx = _constants.find(con);
3292     if (idx != -1 && _constants.at(idx).can_be_reused()) {
3293       _constants.adr_at(idx)->inc_freq(con.freq());  // increase the frequency by the current value
3294       return;
3295     }
3296   }
3297   (void) _constants.append(con);
3298 }
3299 
3300 Compile::Constant Compile::ConstantTable::add(MachConstantNode* n, BasicType type, jvalue value) {
3301   Block* b = Compile::current()->cfg()->_bbs[n->_idx];
3302   Constant con(type, value, b->_freq);
3303   add(con);
3304   return con;
3305 }
3306 
3307 Compile::Constant Compile::ConstantTable::add(Metadata* metadata) {
3308   Constant con(metadata);
3309   add(con);
3310   return con;
3311 }
3312 
3313 Compile::Constant Compile::ConstantTable::add(MachConstantNode* n, MachOper* oper) {
3314   jvalue value;
3315   BasicType type = oper->type()->basic_type();
3316   switch (type) {
3317   case T_LONG:    value.j = oper->constantL(); break;
3318   case T_FLOAT:   value.f = oper->constantF(); break;
3319   case T_DOUBLE:  value.d = oper->constantD(); break;
3320   case T_OBJECT:
3321   case T_ADDRESS: value.l = (jobject) oper->constant(); break;
3322   case T_METADATA: return add((Metadata*)oper->constant()); break;
3323   default: guarantee(false, err_msg_res("unhandled type: %s", type2name(type)));
3324   }
3325   return add(n, type, value);
3326 }
3327 
3328 Compile::Constant Compile::ConstantTable::add_jump_table(MachConstantNode* n) {
3329   jvalue value;
3330   // We can use the node pointer here to identify the right jump-table
3331   // as this method is called from Compile::Fill_buffer right before
3332   // the MachNodes are emitted and the jump-table is filled (means the
3333   // MachNode pointers do not change anymore).
3334   value.l = (jobject) n;
3335   Constant con(T_VOID, value, next_jump_table_freq(), false);  // Labels of a jump-table cannot be reused.
3336   add(con);
3337   return con;
3338 }
3339 
3340 void Compile::ConstantTable::fill_jump_table(CodeBuffer& cb, MachConstantNode* n, GrowableArray<Label*> labels) const {
3341   // If called from Compile::scratch_emit_size do nothing.
3342   if (Compile::current()->in_scratch_emit_size())  return;
3343 
3344   assert(labels.is_nonempty(), "must be");
3345   assert((uint) labels.length() == n->outcnt(), err_msg_res("must be equal: %d == %d", labels.length(), n->outcnt()));
3346 
3347   // Since MachConstantNode::constant_offset() also contains
3348   // table_base_offset() we need to subtract the table_base_offset()
3349   // to get the plain offset into the constant table.
3350   int offset = n->constant_offset() - table_base_offset();
3351 
3352   MacroAssembler _masm(&cb);
3353   address* jump_table_base = (address*) (_masm.code()->consts()->start() + offset);
3354 
3355   for (uint i = 0; i < n->outcnt(); i++) {
3356     address* constant_addr = &jump_table_base[i];
3357     assert(*constant_addr == (((address) n) + i), err_msg_res("all jump-table entries must contain adjusted node pointer: " INTPTR_FORMAT " == " INTPTR_FORMAT, *constant_addr, (((address) n) + i)));
3358     *constant_addr = cb.consts()->target(*labels.at(i), (address) constant_addr);
3359     cb.consts()->relocate((address) constant_addr, relocInfo::internal_word_type);
3360   }
3361 }
3362 
3363 void Compile::dump_inlining() {
3364   if (PrintInlining) {
3365     for (int i = 0; i < _print_inlining_list->length(); i++) {
3366       tty->print(_print_inlining_list->at(i).ss()->as_string());
3367     }
3368   }
3369 }
--- EOF ---