--- old/src/share/vm/opto/parse3.cpp
          +++ new/src/share/vm/opto/parse3.cpp

   1    1  /*
   2    2   * Copyright (c) 1998, 2011, Oracle and/or its affiliates. All rights reserved.
   3    3   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4    4   *
   5    5   * This code is free software; you can redistribute it and/or modify it
   6    6   * under the terms of the GNU General Public License version 2 only, as
   7    7   * published by the Free Software Foundation.
   8    8   *
   9    9   * This code is distributed in the hope that it will be useful, but WITHOUT
  10   10   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11   11   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12   12   * version 2 for more details (a copy is included in the LICENSE file that
  13   13   * accompanied this code).
  14   14   *
  15   15   * You should have received a copy of the GNU General Public License version
  16   16   * 2 along with this work; if not, write to the Free Software Foundation,
  17   17   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18   18   *
  19   19   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20   20   * or visit www.oracle.com if you need additional information or have any
  21   21   * questions.
  22   22   *
  23   23   */
  24   24  
  25   25  #include "precompiled.hpp"
  26   26  #include "compiler/compileLog.hpp"
  27   27  #include "interpreter/linkResolver.hpp"
  28   28  #include "memory/universe.inline.hpp"
  29   29  #include "oops/objArrayKlass.hpp"
  30   30  #include "opto/addnode.hpp"
  31   31  #include "opto/memnode.hpp"
  32   32  #include "opto/parse.hpp"
  33   33  #include "opto/rootnode.hpp"
  34   34  #include "opto/runtime.hpp"
  35   35  #include "opto/subnode.hpp"
  36   36  #include "runtime/deoptimization.hpp"
  37   37  #include "runtime/handles.inline.hpp"
  38   38  
  39   39  //=============================================================================
  40   40  // Helper methods for _get* and _put* bytecodes
  41   41  //=============================================================================
  42   42  bool Parse::static_field_ok_in_clinit(ciField *field, ciMethod *method) {
  43   43    // Could be the field_holder's <clinit> method, or <clinit> for a subklass.
  44   44    // Better to check now than to Deoptimize as soon as we execute
  45   45    assert( field->is_static(), "Only check if field is static");
  46   46    // is_being_initialized() is too generous.  It allows access to statics
  47   47    // by threads that are not running the <clinit> before the <clinit> finishes.
  48   48    // return field->holder()->is_being_initialized();
  49   49  
  50   50    // The following restriction is correct but conservative.
  51   51    // It is also desirable to allow compilation of methods called from <clinit>
  52   52    // but this generated code will need to be made safe for execution by
  53   53    // other threads, or the transition from interpreted to compiled code would
  54   54    // need to be guarded.
  55   55    ciInstanceKlass *field_holder = field->holder();
  56   56  
  57   57    bool access_OK = false;
  58   58    if (method->holder()->is_subclass_of(field_holder)) {
  59   59      if (method->is_static()) {
  60   60        if (method->name() == ciSymbol::class_initializer_name()) {
  61   61          // OK to access static fields inside initializer
  62   62          access_OK = true;
  63   63        }
  64   64      } else {
  65   65        if (method->name() == ciSymbol::object_initializer_name()) {
  66   66          // It's also OK to access static fields inside a constructor,
  67   67          // because any thread calling the constructor must first have
  68   68          // synchronized on the class by executing a '_new' bytecode.
  69   69          access_OK = true;
  70   70        }
  71   71      }
  72   72    }
  73   73  
  74   74    return access_OK;
  75   75  
  76   76  }
  77   77  
  78   78  
  79   79  void Parse::do_field_access(bool is_get, bool is_field) {
  80   80    bool will_link;
  81   81    ciField* field = iter().get_field(will_link);
  82   82    assert(will_link, "getfield: typeflow responsibility");
  83   83  
  84   84    ciInstanceKlass* field_holder = field->holder();
  85   85  
  86   86    if (is_field == field->is_static()) {
  87   87      // Interpreter will throw java_lang_IncompatibleClassChangeError
  88   88      // Check this before allowing <clinit> methods to access static fields
  89   89      uncommon_trap(Deoptimization::Reason_unhandled,
  90   90                    Deoptimization::Action_none);
  91   91      return;
  92   92    }

  93   93  
  94   94    if (!is_field && !field_holder->is_initialized()) {
  95   95      if (!static_field_ok_in_clinit(field, method())) {
  96   96        uncommon_trap(Deoptimization::Reason_uninitialized,
  97   97                      Deoptimization::Action_reinterpret,
  98   98                      NULL, "!static_field_ok_in_clinit");
  99   99        return;
 100  100      }
 101  101    }
 102  102  
      103 +  // Deoptimize on putfield writes to CallSite.target
      104 +  if (!is_get && field->is_call_site_target()) {
      105 +    uncommon_trap(Deoptimization::Reason_unhandled,
      106 +                  Deoptimization::Action_reinterpret,
      107 +                  NULL, "put to CallSite.target field");
      108 +    return;
      109 +  }
      110 +
 103  111    assert(field->will_link(method()->holder(), bc()), "getfield: typeflow responsibility");
 104  112  
 105  113    // Note:  We do not check for an unloaded field type here any more.
 106  114  
 107  115    // Generate code for the object pointer.
 108  116    Node* obj;
 109  117    if (is_field) {
 110  118      int obj_depth = is_get ? 0 : field->type()->size();
 111  119      obj = do_null_check(peek(obj_depth), T_OBJECT);
 112  120      // Compile-time detect of null-exception?

 113  121      if (stopped())  return;
 114  122  
 115  123  #ifdef ASSERT
 116  124      const TypeInstPtr *tjp = TypeInstPtr::make(TypePtr::NotNull, iter().get_declared_field_holder());
 117  125      assert(_gvn.type(obj)->higher_equal(tjp), "cast_up is no longer needed");
 118  126  #endif
 119  127  
 120  128      if (is_get) {
 121  129        --_sp;  // pop receiver before getting
 122  130        do_get_xxx(obj, field, is_field);
 123  131      } else {
 124  132        do_put_xxx(obj, field, is_field);
 125  133        --_sp;  // pop receiver after putting
 126  134      }
 127  135    } else {
 128  136      const TypeInstPtr* tip = TypeInstPtr::make(field_holder->java_mirror());
 129  137      obj = _gvn.makecon(tip);
 130  138      if (is_get) {
 131  139        do_get_xxx(obj, field, is_field);
 132  140      } else {
 133  141        do_put_xxx(obj, field, is_field);
 134  142      }
 135  143    }
 136  144  }
 137  145  
 138  146  
 139  147  void Parse::do_get_xxx(Node* obj, ciField* field, bool is_field) {
 140  148    // Does this field have a constant value?  If so, just push the value.
 141  149    if (field->is_constant()) {
 142  150      if (field->is_static()) {
 143  151        // final static field
 144  152        if (push_constant(field->constant_value()))
 145  153          return;
 146  154      }
 147  155      else {
 148  156        // final non-static field of a trusted class (classes in
 149  157        // java.lang.invoke and sun.invoke packages and subpackages).
 150  158        if (obj->is_Con()) {
 151  159          const TypeOopPtr* oop_ptr = obj->bottom_type()->isa_oopptr();
 152  160          ciObject* constant_oop = oop_ptr->const_oop();
 153  161          ciConstant constant = field->constant_value_of(constant_oop);
 154  162  
 155  163          if (push_constant(constant, true))
 156  164            return;
 157  165        }
 158  166      }
 159  167    }
 160  168  
 161  169    ciType* field_klass = field->type();
 162  170    bool is_vol = field->is_volatile();
 163  171  
 164  172    // Compute address and memory type.
 165  173    int offset = field->offset_in_bytes();
 166  174    const TypePtr* adr_type = C->alias_type(field)->adr_type();
 167  175    Node *adr = basic_plus_adr(obj, obj, offset);
 168  176    BasicType bt = field->layout_type();
 169  177  
 170  178    // Build the resultant type of the load
 171  179    const Type *type;
 172  180  
 173  181    bool must_assert_null = false;
 174  182  
 175  183    if( bt == T_OBJECT ) {
 176  184      if (!field->type()->is_loaded()) {
 177  185        type = TypeInstPtr::BOTTOM;
 178  186        must_assert_null = true;
 179  187      } else if (field->is_constant() && field->is_static()) {
 180  188        // This can happen if the constant oop is non-perm.
 181  189        ciObject* con = field->constant_value().as_object();
 182  190        // Do not "join" in the previous type; it doesn't add value,
 183  191        // and may yield a vacuous result if the field is of interface type.
 184  192        type = TypeOopPtr::make_from_constant(con)->isa_oopptr();
 185  193        assert(type != NULL, "field singleton type must be consistent");
 186  194      } else {
 187  195        type = TypeOopPtr::make_from_klass(field_klass->as_klass());
 188  196      }
 189  197    } else {
 190  198      type = Type::get_const_basic_type(bt);
 191  199    }
 192  200    // Build the load.
 193  201    Node* ld = make_load(NULL, adr, type, bt, adr_type, is_vol);
 194  202  
 195  203    // Adjust Java stack
 196  204    if (type2size[bt] == 1)
 197  205      push(ld);
 198  206    else
 199  207      push_pair(ld);
 200  208  
 201  209    if (must_assert_null) {
 202  210      // Do not take a trap here.  It's possible that the program
 203  211      // will never load the field's class, and will happily see
 204  212      // null values in this field forever.  Don't stumble into a
 205  213      // trap for such a program, or we might get a long series
 206  214      // of useless recompilations.  (Or, we might load a class
 207  215      // which should not be loaded.)  If we ever see a non-null
 208  216      // value, we will then trap and recompile.  (The trap will
 209  217      // not need to mention the class index, since the class will
 210  218      // already have been loaded if we ever see a non-null value.)
 211  219      // uncommon_trap(iter().get_field_signature_index());
 212  220  #ifndef PRODUCT
 213  221      if (PrintOpto && (Verbose || WizardMode)) {
 214  222        method()->print_name(); tty->print_cr(" asserting nullness of field at bci: %d", bci());
 215  223      }
 216  224  #endif
 217  225      if (C->log() != NULL) {
 218  226        C->log()->elem("assert_null reason='field' klass='%d'",
 219  227                       C->log()->identify(field->type()));
 220  228      }
 221  229      // If there is going to be a trap, put it at the next bytecode:
 222  230      set_bci(iter().next_bci());
 223  231      do_null_assert(peek(), T_OBJECT);
 224  232      set_bci(iter().cur_bci()); // put it back
 225  233    }
 226  234  
 227  235    // If reference is volatile, prevent following memory ops from
 228  236    // floating up past the volatile read.  Also prevents commoning
 229  237    // another volatile read.
 230  238    if (field->is_volatile()) {
 231  239      // Memory barrier includes bogus read of value to force load BEFORE membar
 232  240      insert_mem_bar(Op_MemBarAcquire, ld);
 233  241    }
 234  242  }
 235  243  
 236  244  void Parse::do_put_xxx(Node* obj, ciField* field, bool is_field) {
 237  245    bool is_vol = field->is_volatile();
 238  246    // If reference is volatile, prevent following memory ops from
 239  247    // floating down past the volatile write.  Also prevents commoning
 240  248    // another volatile read.
 241  249    if (is_vol)  insert_mem_bar(Op_MemBarRelease);
 242  250  
 243  251    // Compute address and memory type.
 244  252    int offset = field->offset_in_bytes();
 245  253    const TypePtr* adr_type = C->alias_type(field)->adr_type();
 246  254    Node* adr = basic_plus_adr(obj, obj, offset);
 247  255    BasicType bt = field->layout_type();
 248  256    // Value to be stored
 249  257    Node* val = type2size[bt] == 1 ? pop() : pop_pair();
 250  258    // Round doubles before storing
 251  259    if (bt == T_DOUBLE)  val = dstore_rounding(val);
 252  260  
 253  261    // Store the value.
 254  262    Node* store;
 255  263    if (bt == T_OBJECT) {
 256  264      const TypeOopPtr* field_type;
 257  265      if (!field->type()->is_loaded()) {
 258  266        field_type = TypeInstPtr::BOTTOM;
 259  267      } else {
 260  268        field_type = TypeOopPtr::make_from_klass(field->type()->as_klass());
 261  269      }
 262  270      store = store_oop_to_object( control(), obj, adr, adr_type, val, field_type, bt);
 263  271    } else {
 264  272      store = store_to_memory( control(), adr, val, bt, adr_type, is_vol );
 265  273    }
 266  274  
 267  275    // If reference is volatile, prevent following volatiles ops from
 268  276    // floating up before the volatile write.
 269  277    if (is_vol) {
 270  278      // First place the specific membar for THIS volatile index. This first
 271  279      // membar is dependent on the store, keeping any other membars generated
 272  280      // below from floating up past the store.
 273  281      int adr_idx = C->get_alias_index(adr_type);
 274  282      insert_mem_bar_volatile(Op_MemBarVolatile, adr_idx, store);
 275  283  
 276  284      // Now place a membar for AliasIdxBot for the unknown yet-to-be-parsed
 277  285      // volatile alias indices. Skip this if the membar is redundant.
 278  286      if (adr_idx != Compile::AliasIdxBot) {
 279  287        insert_mem_bar_volatile(Op_MemBarVolatile, Compile::AliasIdxBot, store);
 280  288      }
 281  289  
 282  290      // Finally, place alias-index-specific membars for each volatile index
 283  291      // that isn't the adr_idx membar. Typically there's only 1 or 2.
 284  292      for( int i = Compile::AliasIdxRaw; i < C->num_alias_types(); i++ ) {
 285  293        if (i != adr_idx && C->alias_type(i)->is_volatile()) {
 286  294          insert_mem_bar_volatile(Op_MemBarVolatile, i, store);
 287  295        }
 288  296      }
 289  297    }
 290  298  
 291  299    // If the field is final, the rules of Java say we are in <init> or <clinit>.
 292  300    // Note the presence of writes to final non-static fields, so that we
 293  301    // can insert a memory barrier later on to keep the writes from floating
 294  302    // out of the constructor.
 295  303    if (is_field && field->is_final()) {
 296  304      set_wrote_final(true);
 297  305    }
 298  306  }
 299  307  
 300  308  
 301  309  bool Parse::push_constant(ciConstant constant, bool require_constant) {
 302  310    switch (constant.basic_type()) {
 303  311    case T_BOOLEAN:  push( intcon(constant.as_boolean()) ); break;
 304  312    case T_INT:      push( intcon(constant.as_int())     ); break;
 305  313    case T_CHAR:     push( intcon(constant.as_char())    ); break;
 306  314    case T_BYTE:     push( intcon(constant.as_byte())    ); break;
 307  315    case T_SHORT:    push( intcon(constant.as_short())   ); break;
 308  316    case T_FLOAT:    push( makecon(TypeF::make(constant.as_float())) );  break;
 309  317    case T_DOUBLE:   push_pair( makecon(TypeD::make(constant.as_double())) );  break;
 310  318    case T_LONG:     push_pair( longcon(constant.as_long()) ); break;
 311  319    case T_ARRAY:
 312  320    case T_OBJECT: {
 313  321      // cases:
 314  322      //   can_be_constant    = (oop not scavengable || ScavengeRootsInCode != 0)
 315  323      //   should_be_constant = (oop not scavengable || ScavengeRootsInCode >= 2)
 316  324      // An oop is not scavengable if it is in the perm gen.
 317  325      ciObject* oop_constant = constant.as_object();
 318  326      if (oop_constant->is_null_object()) {
 319  327        push( zerocon(T_OBJECT) );
 320  328        break;
 321  329      } else if (require_constant || oop_constant->should_be_constant()) {
 322  330        push( makecon(TypeOopPtr::make_from_constant(oop_constant, require_constant)) );
 323  331        break;
 324  332      } else {
 325  333        // we cannot inline the oop, but we can use it later to narrow a type
 326  334        return false;
 327  335      }
 328  336    }
 329  337    case T_ILLEGAL: {
 330  338      // Invalid ciConstant returned due to OutOfMemoryError in the CI
 331  339      assert(C->env()->failing(), "otherwise should not see this");
 332  340      // These always occur because of object types; we are going to
 333  341      // bail out anyway, so make the stack depths match up
 334  342      push( zerocon(T_OBJECT) );
 335  343      return false;
 336  344    }
 337  345    default:
 338  346      ShouldNotReachHere();
 339  347      return false;
 340  348    }
 341  349  
 342  350    // success
 343  351    return true;
 344  352  }
 345  353  
 346  354  
 347  355  
 348  356  //=============================================================================
 349  357  void Parse::do_anewarray() {
 350  358    bool will_link;
 351  359    ciKlass* klass = iter().get_klass(will_link);
 352  360  
 353  361    // Uncommon Trap when class that array contains is not loaded
 354  362    // we need the loaded class for the rest of graph; do not
 355  363    // initialize the container class (see Java spec)!!!
 356  364    assert(will_link, "anewarray: typeflow responsibility");
 357  365  
 358  366    ciObjArrayKlass* array_klass = ciObjArrayKlass::make(klass);
 359  367    // Check that array_klass object is loaded
 360  368    if (!array_klass->is_loaded()) {
 361  369      // Generate uncommon_trap for unloaded array_class
 362  370      uncommon_trap(Deoptimization::Reason_unloaded,
 363  371                    Deoptimization::Action_reinterpret,
 364  372                    array_klass);
 365  373      return;
 366  374    }
 367  375  
 368  376    kill_dead_locals();
 369  377  
 370  378    const TypeKlassPtr* array_klass_type = TypeKlassPtr::make(array_klass);
 371  379    Node* count_val = pop();
 372  380    Node* obj = new_array(makecon(array_klass_type), count_val, 1);
 373  381    push(obj);
 374  382  }
 375  383  
 376  384  
 377  385  void Parse::do_newarray(BasicType elem_type) {
 378  386    kill_dead_locals();
 379  387  
 380  388    Node*   count_val = pop();
 381  389    const TypeKlassPtr* array_klass = TypeKlassPtr::make(ciTypeArrayKlass::make(elem_type));
 382  390    Node*   obj = new_array(makecon(array_klass), count_val, 1);
 383  391    // Push resultant oop onto stack
 384  392    push(obj);
 385  393  }
 386  394  
 387  395  // Expand simple expressions like new int[3][5] and new Object[2][nonConLen].
 388  396  // Also handle the degenerate 1-dimensional case of anewarray.
 389  397  Node* Parse::expand_multianewarray(ciArrayKlass* array_klass, Node* *lengths, int ndimensions, int nargs) {
 390  398    Node* length = lengths[0];
 391  399    assert(length != NULL, "");
 392  400    Node* array = new_array(makecon(TypeKlassPtr::make(array_klass)), length, nargs);
 393  401    if (ndimensions > 1) {
 394  402      jint length_con = find_int_con(length, -1);
 395  403      guarantee(length_con >= 0, "non-constant multianewarray");
 396  404      ciArrayKlass* array_klass_1 = array_klass->as_obj_array_klass()->element_klass()->as_array_klass();
 397  405      const TypePtr* adr_type = TypeAryPtr::OOPS;
 398  406      const TypeOopPtr*    elemtype = _gvn.type(array)->is_aryptr()->elem()->make_oopptr();
 399  407      const intptr_t header   = arrayOopDesc::base_offset_in_bytes(T_OBJECT);
 400  408      for (jint i = 0; i < length_con; i++) {
 401  409        Node*    elem   = expand_multianewarray(array_klass_1, &lengths[1], ndimensions-1, nargs);
 402  410        intptr_t offset = header + ((intptr_t)i << LogBytesPerHeapOop);
 403  411        Node*    eaddr  = basic_plus_adr(array, offset);
 404  412        store_oop_to_array(control(), array, eaddr, adr_type, elem, elemtype, T_OBJECT);
 405  413      }
 406  414    }
 407  415    return array;
 408  416  }
 409  417  
 410  418  void Parse::do_multianewarray() {
 411  419    int ndimensions = iter().get_dimensions();
 412  420  
 413  421    // the m-dimensional array
 414  422    bool will_link;
 415  423    ciArrayKlass* array_klass = iter().get_klass(will_link)->as_array_klass();
 416  424    assert(will_link, "multianewarray: typeflow responsibility");
 417  425  
 418  426    // Note:  Array classes are always initialized; no is_initialized check.
 419  427  
 420  428    kill_dead_locals();
 421  429  
 422  430    // get the lengths from the stack (first dimension is on top)
 423  431    Node** length = NEW_RESOURCE_ARRAY(Node*, ndimensions + 1);
 424  432    length[ndimensions] = NULL;  // terminating null for make_runtime_call
 425  433    int j;
 426  434    for (j = ndimensions-1; j >= 0 ; j--) length[j] = pop();
 427  435  
 428  436    // The original expression was of this form: new T[length0][length1]...
 429  437    // It is often the case that the lengths are small (except the last).
 430  438    // If that happens, use the fast 1-d creator a constant number of times.
 431  439    const jint expand_limit = MIN2((juint)MultiArrayExpandLimit, (juint)100);
 432  440    jint expand_count = 1;        // count of allocations in the expansion
 433  441    jint expand_fanout = 1;       // running total fanout
 434  442    for (j = 0; j < ndimensions-1; j++) {
 435  443      jint dim_con = find_int_con(length[j], -1);
 436  444      expand_fanout *= dim_con;
 437  445      expand_count  += expand_fanout; // count the level-J sub-arrays
 438  446      if (dim_con <= 0
 439  447          || dim_con > expand_limit
 440  448          || expand_count > expand_limit) {
 441  449        expand_count = 0;
 442  450        break;
 443  451      }
 444  452    }
 445  453  
 446  454    // Can use multianewarray instead of [a]newarray if only one dimension,
 447  455    // or if all non-final dimensions are small constants.
 448  456    if (ndimensions == 1 || (1 <= expand_count && expand_count <= expand_limit)) {
 449  457      Node* obj = NULL;
 450  458      // Set the original stack and the reexecute bit for the interpreter
 451  459      // to reexecute the multianewarray bytecode if deoptimization happens.
 452  460      // Do it unconditionally even for one dimension multianewarray.
 453  461      // Note: the reexecute bit will be set in GraphKit::add_safepoint_edges()
 454  462      // when AllocateArray node for newarray is created.
 455  463      { PreserveReexecuteState preexecs(this);
 456  464        _sp += ndimensions;
 457  465        // Pass 0 as nargs since uncommon trap code does not need to restore stack.
 458  466        obj = expand_multianewarray(array_klass, &length[0], ndimensions, 0);
 459  467      } //original reexecute and sp are set back here
 460  468      push(obj);
 461  469      return;
 462  470    }
 463  471  
 464  472    address fun = NULL;
 465  473    switch (ndimensions) {
 466  474    case 1: ShouldNotReachHere(); break;
 467  475    case 2: fun = OptoRuntime::multianewarray2_Java(); break;
 468  476    case 3: fun = OptoRuntime::multianewarray3_Java(); break;
 469  477    case 4: fun = OptoRuntime::multianewarray4_Java(); break;
 470  478    case 5: fun = OptoRuntime::multianewarray5_Java(); break;
 471  479    };
 472  480    Node* c = NULL;
 473  481  
 474  482    if (fun != NULL) {
 475  483      c = make_runtime_call(RC_NO_LEAF | RC_NO_IO,
 476  484                            OptoRuntime::multianewarray_Type(ndimensions),
 477  485                            fun, NULL, TypeRawPtr::BOTTOM,
 478  486                            makecon(TypeKlassPtr::make(array_klass)),
 479  487                            length[0], length[1], length[2],
 480  488                            length[3], length[4]);
 481  489    } else {
 482  490      // Create a java array for dimension sizes
 483  491      Node* dims = NULL;
 484  492      { PreserveReexecuteState preexecs(this);
 485  493        _sp += ndimensions;
 486  494        Node* dims_array_klass = makecon(TypeKlassPtr::make(ciArrayKlass::make(ciType::make(T_INT))));
 487  495        dims = new_array(dims_array_klass, intcon(ndimensions), 0);
 488  496  
 489  497        // Fill-in it with values
 490  498        for (j = 0; j < ndimensions; j++) {
 491  499          Node *dims_elem = array_element_address(dims, intcon(j), T_INT);
 492  500          store_to_memory(control(), dims_elem, length[j], T_INT, TypeAryPtr::INTS);
 493  501        }
 494  502      }
 495  503  
 496  504      c = make_runtime_call(RC_NO_LEAF | RC_NO_IO,
 497  505                            OptoRuntime::multianewarrayN_Type(),
 498  506                            OptoRuntime::multianewarrayN_Java(), NULL, TypeRawPtr::BOTTOM,
 499  507                            makecon(TypeKlassPtr::make(array_klass)),
 500  508                            dims);
 501  509    }
 502  510  
 503  511    Node* res = _gvn.transform(new (C, 1) ProjNode(c, TypeFunc::Parms));
 504  512  
 505  513    const Type* type = TypeOopPtr::make_from_klass_raw(array_klass);
 506  514  
 507  515    // Improve the type:  We know it's not null, exact, and of a given length.
 508  516    type = type->is_ptr()->cast_to_ptr_type(TypePtr::NotNull);
 509  517    type = type->is_aryptr()->cast_to_exactness(true);
 510  518  
 511  519    const TypeInt* ltype = _gvn.find_int_type(length[0]);
 512  520    if (ltype != NULL)
 513  521      type = type->is_aryptr()->cast_to_size(ltype);
 514  522  
 515  523      // We cannot sharpen the nested sub-arrays, since the top level is mutable.
 516  524  
 517  525    Node* cast = _gvn.transform( new (C, 2) CheckCastPPNode(control(), res, type) );
 518  526    push(cast);
 519  527  
 520  528    // Possible improvements:
 521  529    // - Make a fast path for small multi-arrays.  (W/ implicit init. loops.)
 522  530    // - Issue CastII against length[*] values, to TypeInt::POS.
 523  531  }

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