1 /*
   2  * Copyright (c) 2005, 2020, 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 #ifndef SHARE_C1_C1_LIRGENERATOR_HPP
  26 #define SHARE_C1_C1_LIRGENERATOR_HPP
  27 
  28 #include "c1/c1_Decorators.hpp"
  29 #include "c1/c1_Instruction.hpp"
  30 #include "c1/c1_LIR.hpp"
  31 #include "ci/ciMethodData.hpp"
  32 #include "gc/shared/barrierSet.hpp"
  33 #include "jfr/support/jfrIntrinsics.hpp"
  34 #include "utilities/macros.hpp"
  35 #include "utilities/sizes.hpp"
  36 
  37 class BarrierSetC1;
  38 
  39 // The classes responsible for code emission and register allocation
  40 
  41 
  42 class LIRGenerator;
  43 class LIREmitter;
  44 class Invoke;
  45 class LIRItem;
  46 
  47 typedef GrowableArray<LIRItem*> LIRItemList;
  48 
  49 class C1SwitchRange: public CompilationResourceObj {
  50  private:
  51   int _low_key;
  52   int _high_key;
  53   BlockBegin* _sux;
  54  public:
  55   C1SwitchRange(int start_key, BlockBegin* sux): _low_key(start_key), _high_key(start_key), _sux(sux) {}
  56   void set_high_key(int key) { _high_key = key; }
  57 
  58   int high_key() const { return _high_key; }
  59   int low_key() const { return _low_key; }
  60   BlockBegin* sux() const { return _sux; }
  61 };
  62 
  63 typedef GrowableArray<C1SwitchRange*> SwitchRangeArray;
  64 typedef GrowableArray<C1SwitchRange*> SwitchRangeList;
  65 
  66 class ResolveNode;
  67 
  68 typedef GrowableArray<ResolveNode*> NodeList;
  69 
  70 // Node objects form a directed graph of LIR_Opr
  71 // Edges between Nodes represent moves from one Node to its destinations
  72 class ResolveNode: public CompilationResourceObj {
  73  private:
  74   LIR_Opr    _operand;       // the source or destinaton
  75   NodeList   _destinations;  // for the operand
  76   bool       _assigned;      // Value assigned to this Node?
  77   bool       _visited;       // Node already visited?
  78   bool       _start_node;    // Start node already visited?
  79 
  80  public:
  81   ResolveNode(LIR_Opr operand)
  82     : _operand(operand)
  83     , _assigned(false)
  84     , _visited(false)
  85     , _start_node(false) {};
  86 
  87   // accessors
  88   LIR_Opr operand() const           { return _operand; }
  89   int no_of_destinations() const    { return _destinations.length(); }
  90   ResolveNode* destination_at(int i)     { return _destinations.at(i); }
  91   bool assigned() const             { return _assigned; }
  92   bool visited() const              { return _visited; }
  93   bool start_node() const           { return _start_node; }
  94 
  95   // modifiers
  96   void append(ResolveNode* dest)         { _destinations.append(dest); }
  97   void set_assigned()               { _assigned = true; }
  98   void set_visited()                { _visited = true; }
  99   void set_start_node()             { _start_node = true; }
 100 };
 101 
 102 
 103 // This is shared state to be used by the PhiResolver so the operand
 104 // arrays don't have to be reallocated for each resolution.
 105 class PhiResolverState: public CompilationResourceObj {
 106   friend class PhiResolver;
 107 
 108  private:
 109   NodeList _virtual_operands; // Nodes where the operand is a virtual register
 110   NodeList _other_operands;   // Nodes where the operand is not a virtual register
 111   NodeList _vreg_table;       // Mapping from virtual register to Node
 112 
 113  public:
 114   PhiResolverState() {}
 115 
 116   void reset();
 117 };
 118 
 119 
 120 // class used to move value of phi operand to phi function
 121 class PhiResolver: public CompilationResourceObj {
 122  private:
 123   LIRGenerator*     _gen;
 124   PhiResolverState& _state; // temporary state cached by LIRGenerator
 125 
 126   ResolveNode*   _loop;
 127   LIR_Opr _temp;
 128 
 129   // access to shared state arrays
 130   NodeList& virtual_operands() { return _state._virtual_operands; }
 131   NodeList& other_operands()   { return _state._other_operands;   }
 132   NodeList& vreg_table()       { return _state._vreg_table;       }
 133 
 134   ResolveNode* create_node(LIR_Opr opr, bool source);
 135   ResolveNode* source_node(LIR_Opr opr)      { return create_node(opr, true); }
 136   ResolveNode* destination_node(LIR_Opr opr) { return create_node(opr, false); }
 137 
 138   void emit_move(LIR_Opr src, LIR_Opr dest);
 139   void move_to_temp(LIR_Opr src);
 140   void move_temp_to(LIR_Opr dest);
 141   void move(ResolveNode* src, ResolveNode* dest);
 142 
 143   LIRGenerator* gen() {
 144     return _gen;
 145   }
 146 
 147  public:
 148   PhiResolver(LIRGenerator* _lir_gen);
 149   ~PhiResolver();
 150 
 151   void move(LIR_Opr src, LIR_Opr dest);
 152 };
 153 
 154 
 155 // only the classes below belong in the same file
 156 class LIRGenerator: public InstructionVisitor, public BlockClosure {
 157  // LIRGenerator should never get instatiated on the heap.
 158  private:
 159   void* operator new(size_t size) throw();
 160   void* operator new[](size_t size) throw();
 161   void operator delete(void* p) { ShouldNotReachHere(); }
 162   void operator delete[](void* p) { ShouldNotReachHere(); }
 163 
 164   Compilation*  _compilation;
 165   ciMethod*     _method;    // method that we are compiling
 166   PhiResolverState  _resolver_state;
 167   BlockBegin*   _block;
 168   int           _virtual_register_number;
 169   Values        _instruction_for_operand;
 170   BitMap2D      _vreg_flags; // flags which can be set on a per-vreg basis
 171   LIR_List*     _lir;
 172 
 173   LIRGenerator* gen() {
 174     return this;
 175   }
 176 
 177   void print_if_not_loaded(const NewInstance* new_instance) PRODUCT_RETURN;
 178 
 179  public:
 180 #ifdef ASSERT
 181   LIR_List* lir(const char * file, int line) const {
 182     _lir->set_file_and_line(file, line);
 183     return _lir;
 184   }
 185 #endif
 186   LIR_List* lir() const {
 187     return _lir;
 188   }
 189 
 190  private:
 191   // a simple cache of constants used within a block
 192   GrowableArray<LIR_Const*>       _constants;
 193   LIR_OprList                     _reg_for_constants;
 194   Values                          _unpinned_constants;
 195 
 196   friend class PhiResolver;
 197 
 198  public:
 199   // unified bailout support
 200   void bailout(const char* msg) const            { compilation()->bailout(msg); }
 201   bool bailed_out() const                        { return compilation()->bailed_out(); }
 202 
 203   void block_do_prolog(BlockBegin* block);
 204   void block_do_epilog(BlockBegin* block);
 205 
 206   // register allocation
 207   LIR_Opr rlock(Value instr);                      // lock a free register
 208   LIR_Opr rlock_result(Value instr);
 209   LIR_Opr rlock_result(Value instr, BasicType type);
 210   LIR_Opr rlock_byte(BasicType type);
 211   LIR_Opr rlock_callee_saved(BasicType type);
 212 
 213   // get a constant into a register and get track of what register was used
 214   LIR_Opr load_constant(Constant* x);
 215   LIR_Opr load_constant(LIR_Const* constant);
 216 
 217   // Given an immediate value, return an operand usable in logical ops.
 218   LIR_Opr load_immediate(int x, BasicType type);
 219 
 220   void  set_result(Value x, LIR_Opr opr)           {
 221     assert(opr->is_valid(), "must set to valid value");
 222     assert(x->operand()->is_illegal(), "operand should never change");
 223     assert(!opr->is_register() || opr->is_virtual(), "should never set result to a physical register");
 224     x->set_operand(opr);
 225     assert(opr == x->operand(), "must be");
 226     if (opr->is_virtual()) {
 227       _instruction_for_operand.at_put_grow(opr->vreg_number(), x, NULL);
 228     }
 229   }
 230   void  set_no_result(Value x)                     { assert(!x->has_uses(), "can't have use"); x->clear_operand(); }
 231 
 232   friend class LIRItem;
 233 
 234   LIR_Opr round_item(LIR_Opr opr);
 235   LIR_Opr force_to_spill(LIR_Opr value, BasicType t);
 236 
 237   PhiResolverState& resolver_state() { return _resolver_state; }
 238 
 239   void  move_to_phi(PhiResolver* resolver, Value cur_val, Value sux_val);
 240   void  move_to_phi(ValueStack* cur_state);
 241 
 242   // platform dependent
 243   LIR_Opr getThreadPointer();
 244 
 245  private:
 246   // code emission
 247   void do_ArithmeticOp_Long(ArithmeticOp* x);
 248   void do_ArithmeticOp_Int (ArithmeticOp* x);
 249   void do_ArithmeticOp_FPU (ArithmeticOp* x);
 250 
 251   void do_RegisterFinalizer(Intrinsic* x);
 252   void do_isInstance(Intrinsic* x);
 253   void do_isPrimitive(Intrinsic* x);
 254   void do_getClass(Intrinsic* x);
 255   void do_currentThread(Intrinsic* x);
 256   void do_FmaIntrinsic(Intrinsic* x);
 257   void do_MathIntrinsic(Intrinsic* x);
 258   void do_LibmIntrinsic(Intrinsic* x);
 259   void do_ArrayCopy(Intrinsic* x);
 260   void do_CompareAndSwap(Intrinsic* x, ValueType* type);
 261   void do_NIOCheckIndex(Intrinsic* x);
 262   void do_FPIntrinsics(Intrinsic* x);
 263   void do_Reference_get(Intrinsic* x);
 264   void do_update_CRC32(Intrinsic* x);
 265   void do_update_CRC32C(Intrinsic* x);
 266   void do_vectorizedMismatch(Intrinsic* x);
 267 
 268  public:
 269   LIR_Opr call_runtime(BasicTypeArray* signature, LIRItemList* args, address entry, ValueType* result_type, CodeEmitInfo* info);
 270   LIR_Opr call_runtime(BasicTypeArray* signature, LIR_OprList* args, address entry, ValueType* result_type, CodeEmitInfo* info);
 271 
 272   // convenience functions
 273   LIR_Opr call_runtime(Value arg1, address entry, ValueType* result_type, CodeEmitInfo* info);
 274   LIR_Opr call_runtime(Value arg1, Value arg2, address entry, ValueType* result_type, CodeEmitInfo* info);
 275 
 276   // Access API
 277 
 278  private:
 279   BarrierSetC1 *_barrier_set;
 280 
 281  public:
 282   void access_store_at(DecoratorSet decorators, BasicType type,
 283                        LIRItem& base, LIR_Opr offset, LIR_Opr value,
 284                        CodeEmitInfo* patch_info = NULL, CodeEmitInfo* store_emit_info = NULL);
 285 
 286   void access_load_at(DecoratorSet decorators, BasicType type,
 287                       LIRItem& base, LIR_Opr offset, LIR_Opr result,
 288                       CodeEmitInfo* patch_info = NULL, CodeEmitInfo* load_emit_info = NULL);
 289 
 290   void access_load(DecoratorSet decorators, BasicType type,
 291                    LIR_Opr addr, LIR_Opr result);
 292 
 293   LIR_Opr access_atomic_cmpxchg_at(DecoratorSet decorators, BasicType type,
 294                                    LIRItem& base, LIRItem& offset, LIRItem& cmp_value, LIRItem& new_value);
 295 
 296   LIR_Opr access_atomic_xchg_at(DecoratorSet decorators, BasicType type,
 297                                 LIRItem& base, LIRItem& offset, LIRItem& value);
 298 
 299   LIR_Opr access_atomic_add_at(DecoratorSet decorators, BasicType type,
 300                                LIRItem& base, LIRItem& offset, LIRItem& value);
 301 
 302   LIR_Opr access_resolve(DecoratorSet decorators, LIR_Opr obj);
 303 
 304   // These need to guarantee JMM volatile semantics are preserved on each platform
 305   // and requires one implementation per architecture.
 306   LIR_Opr atomic_cmpxchg(BasicType type, LIR_Opr addr, LIRItem& cmp_value, LIRItem& new_value);
 307   LIR_Opr atomic_xchg(BasicType type, LIR_Opr addr, LIRItem& new_value);
 308   LIR_Opr atomic_add(BasicType type, LIR_Opr addr, LIRItem& new_value);
 309 
 310 #ifdef CARDTABLEBARRIERSET_POST_BARRIER_HELPER
 311   virtual void CardTableBarrierSet_post_barrier_helper(LIR_OprDesc* addr, LIR_Const* card_table_base);
 312 #endif
 313 
 314   // specific implementations
 315   void array_store_check(LIR_Opr value, LIR_Opr array, CodeEmitInfo* store_check_info, ciMethod* profiled_method, int profiled_bci);
 316 
 317   static LIR_Opr result_register_for(ValueType* type, bool callee = false);
 318 
 319   ciObject* get_jobject_constant(Value value);
 320 
 321   LIRItemList* invoke_visit_arguments(Invoke* x);
 322   void invoke_load_arguments(Invoke* x, LIRItemList* args, const LIR_OprList* arg_list);
 323 
 324   void trace_block_entry(BlockBegin* block);
 325 
 326   // volatile field operations are never patchable because a klass
 327   // must be loaded to know it's volatile which means that the offset
 328   // it always known as well.
 329   void volatile_field_store(LIR_Opr value, LIR_Address* address, CodeEmitInfo* info);
 330   void volatile_field_load(LIR_Address* address, LIR_Opr result, CodeEmitInfo* info);
 331 
 332   void put_Object_unsafe(LIR_Opr src, LIR_Opr offset, LIR_Opr data, BasicType type, bool is_volatile);
 333   void get_Object_unsafe(LIR_Opr dest, LIR_Opr src, LIR_Opr offset, BasicType type, bool is_volatile);
 334 
 335   void arithmetic_call_op (Bytecodes::Code code, LIR_Opr result, LIR_OprList* args);
 336 
 337   void increment_counter(address counter, BasicType type, int step = 1);
 338   void increment_counter(LIR_Address* addr, int step = 1);
 339 
 340   // is_strictfp is only needed for mul and div (and only generates different code on i486)
 341   void arithmetic_op(Bytecodes::Code code, LIR_Opr result, LIR_Opr left, LIR_Opr right, bool is_strictfp, LIR_Opr tmp, CodeEmitInfo* info = NULL);
 342   // machine dependent.  returns true if it emitted code for the multiply
 343   bool strength_reduce_multiply(LIR_Opr left, jint constant, LIR_Opr result, LIR_Opr tmp);
 344 
 345   void store_stack_parameter (LIR_Opr opr, ByteSize offset_from_sp_in_bytes);
 346 
 347   void klass2reg_with_patching(LIR_Opr r, ciMetadata* obj, CodeEmitInfo* info, bool need_resolve = false);
 348 
 349   // this loads the length and compares against the index
 350   void array_range_check          (LIR_Opr array, LIR_Opr index, CodeEmitInfo* null_check_info, CodeEmitInfo* range_check_info);
 351   // For java.nio.Buffer.checkIndex
 352   void nio_range_check            (LIR_Opr buffer, LIR_Opr index, LIR_Opr result, CodeEmitInfo* info);
 353 
 354   void arithmetic_op_int  (Bytecodes::Code code, LIR_Opr result, LIR_Opr left, LIR_Opr right, LIR_Opr tmp);
 355   void arithmetic_op_long (Bytecodes::Code code, LIR_Opr result, LIR_Opr left, LIR_Opr right, CodeEmitInfo* info = NULL);
 356   void arithmetic_op_fpu  (Bytecodes::Code code, LIR_Opr result, LIR_Opr left, LIR_Opr right, bool is_strictfp, LIR_Opr tmp = LIR_OprFact::illegalOpr);
 357 
 358   void shift_op   (Bytecodes::Code code, LIR_Opr dst_reg, LIR_Opr value, LIR_Opr count, LIR_Opr tmp);
 359 
 360   void logic_op   (Bytecodes::Code code, LIR_Opr dst_reg, LIR_Opr left, LIR_Opr right);
 361 
 362   void monitor_enter (LIR_Opr object, LIR_Opr lock, LIR_Opr hdr, LIR_Opr scratch, int monitor_no, CodeEmitInfo* info_for_exception, CodeEmitInfo* info);
 363   void monitor_exit  (LIR_Opr object, LIR_Opr lock, LIR_Opr hdr, LIR_Opr scratch, int monitor_no);
 364 
 365   void new_instance    (LIR_Opr  dst, ciInstanceKlass* klass, bool is_unresolved, LIR_Opr  scratch1, LIR_Opr  scratch2, LIR_Opr  scratch3,  LIR_Opr scratch4, LIR_Opr  klass_reg, CodeEmitInfo* info);
 366 
 367   // machine dependent
 368   void cmp_mem_int(LIR_Condition condition, LIR_Opr base, int disp, int c, CodeEmitInfo* info);
 369   void cmp_reg_mem(LIR_Condition condition, LIR_Opr reg, LIR_Opr base, int disp, BasicType type, CodeEmitInfo* info);
 370 
 371   void arraycopy_helper(Intrinsic* x, int* flags, ciArrayKlass** expected_type);
 372 
 373   // returns a LIR_Address to address an array location.  May also
 374   // emit some code as part of address calculation.  If
 375   // needs_card_mark is true then compute the full address for use by
 376   // both the store and the card mark.
 377   LIR_Address* generate_address(LIR_Opr base,
 378                                 LIR_Opr index, int shift,
 379                                 int disp,
 380                                 BasicType type);
 381   LIR_Address* generate_address(LIR_Opr base, int disp, BasicType type) {
 382     return generate_address(base, LIR_OprFact::illegalOpr, 0, disp, type);
 383   }
 384   LIR_Address* emit_array_address(LIR_Opr array_opr, LIR_Opr index_opr, BasicType type);
 385 
 386   // the helper for generate_address
 387   void add_large_constant(LIR_Opr src, int c, LIR_Opr dest);
 388 
 389   // machine preferences and characteristics
 390   bool can_inline_as_constant(Value i S390_ONLY(COMMA int bits = 20)) const;
 391   bool can_inline_as_constant(LIR_Const* c) const;
 392   bool can_store_as_constant(Value i, BasicType type) const;
 393 
 394   LIR_Opr safepoint_poll_register();
 395 
 396   void profile_branch(If* if_instr, If::Condition cond);
 397   void increment_event_counter_impl(CodeEmitInfo* info,
 398                                     ciMethod *method, LIR_Opr step, int frequency,
 399                                     int bci, bool backedge, bool notify);
 400   void increment_event_counter(CodeEmitInfo* info, LIR_Opr step, int bci, bool backedge);
 401   void increment_invocation_counter(CodeEmitInfo *info) {
 402     if (compilation()->count_invocations()) {
 403       increment_event_counter(info, LIR_OprFact::intConst(InvocationCounter::count_increment), InvocationEntryBci, false);
 404     }
 405   }
 406   void increment_backedge_counter(CodeEmitInfo* info, int bci) {
 407     if (compilation()->count_backedges()) {
 408       increment_event_counter(info, LIR_OprFact::intConst(InvocationCounter::count_increment), bci, true);
 409     }
 410   }
 411   void increment_backedge_counter_conditionally(LIR_Condition cond, LIR_Opr left, LIR_Opr right, CodeEmitInfo* info, int left_bci, int right_bci, int bci);
 412   void increment_backedge_counter(CodeEmitInfo* info, LIR_Opr step, int bci) {
 413     if (compilation()->count_backedges()) {
 414       increment_event_counter(info, step, bci, true);
 415     }
 416   }
 417   void decrement_age(CodeEmitInfo* info);
 418   CodeEmitInfo* state_for(Instruction* x, ValueStack* state, bool ignore_xhandler = false);
 419   CodeEmitInfo* state_for(Instruction* x);
 420 
 421   // allocates a virtual register for this instruction if
 422   // one isn't already allocated.  Only for Phi and Local.
 423   LIR_Opr operand_for_instruction(Instruction *x);
 424 
 425   void set_block(BlockBegin* block)              { _block = block; }
 426 
 427   void block_prolog(BlockBegin* block);
 428   void block_epilog(BlockBegin* block);
 429 
 430   void do_root (Instruction* instr);
 431   void walk    (Instruction* instr);
 432 
 433   void bind_block_entry(BlockBegin* block);
 434   void start_block(BlockBegin* block);
 435 
 436   LIR_Opr new_register(BasicType type);
 437   LIR_Opr new_register(Value value)              { return new_register(as_BasicType(value->type())); }
 438   LIR_Opr new_register(ValueType* type)          { return new_register(as_BasicType(type)); }
 439 
 440   // returns a register suitable for doing pointer math
 441   LIR_Opr new_pointer_register() {
 442 #ifdef _LP64
 443     return new_register(T_LONG);
 444 #else
 445     return new_register(T_INT);
 446 #endif
 447   }
 448 
 449   static LIR_Condition lir_cond(If::Condition cond) {
 450     LIR_Condition l = lir_cond_unknown;
 451     switch (cond) {
 452     case If::eql: l = lir_cond_equal;        break;
 453     case If::neq: l = lir_cond_notEqual;     break;
 454     case If::lss: l = lir_cond_less;         break;
 455     case If::leq: l = lir_cond_lessEqual;    break;
 456     case If::geq: l = lir_cond_greaterEqual; break;
 457     case If::gtr: l = lir_cond_greater;      break;
 458     case If::aeq: l = lir_cond_aboveEqual;   break;
 459     case If::beq: l = lir_cond_belowEqual;   break;
 460     default: fatal("You must pass valid If::Condition");
 461     };
 462     return l;
 463   }
 464 
 465 #ifdef __SOFTFP__
 466   void do_soft_float_compare(If *x);
 467 #endif // __SOFTFP__
 468 
 469   SwitchRangeArray* create_lookup_ranges(TableSwitch* x);
 470   SwitchRangeArray* create_lookup_ranges(LookupSwitch* x);
 471   void do_SwitchRanges(SwitchRangeArray* x, LIR_Opr value, BlockBegin* default_sux);
 472 
 473 #ifdef JFR_HAVE_INTRINSICS
 474   void do_ClassIDIntrinsic(Intrinsic* x);
 475   void do_getEventWriter(Intrinsic* x);
 476 #endif
 477 
 478   void do_RuntimeCall(address routine, Intrinsic* x);
 479 
 480   ciKlass* profile_type(ciMethodData* md, int md_first_offset, int md_offset, intptr_t profiled_k,
 481                         Value arg, LIR_Opr& mdp, bool not_null, ciKlass* signature_at_call_k,
 482                         ciKlass* callee_signature_k);
 483   void profile_arguments(ProfileCall* x);
 484   void profile_parameters(Base* x);
 485   void profile_parameters_at_call(ProfileCall* x);
 486   LIR_Opr mask_boolean(LIR_Opr array, LIR_Opr value, CodeEmitInfo*& null_check_info);
 487   LIR_Opr maybe_mask_boolean(StoreIndexed* x, LIR_Opr array, LIR_Opr value, CodeEmitInfo*& null_check_info);
 488 
 489  public:
 490   Compilation*  compilation() const              { return _compilation; }
 491   FrameMap*     frame_map() const                { return _compilation->frame_map(); }
 492   ciMethod*     method() const                   { return _method; }
 493   BlockBegin*   block() const                    { return _block; }
 494   IRScope*      scope() const                    { return block()->scope(); }
 495 
 496   int max_virtual_register_number() const        { return _virtual_register_number; }
 497 
 498   void block_do(BlockBegin* block);
 499 
 500   // Flags that can be set on vregs
 501   enum VregFlag {
 502       must_start_in_memory = 0  // needs to be assigned a memory location at beginning, but may then be loaded in a register
 503     , callee_saved     = 1    // must be in a callee saved register
 504     , byte_reg         = 2    // must be in a byte register
 505     , num_vreg_flags
 506 
 507   };
 508 
 509   LIRGenerator(Compilation* compilation, ciMethod* method)
 510     : _compilation(compilation)
 511     , _method(method)
 512     , _virtual_register_number(LIR_OprDesc::vreg_base)
 513     , _vreg_flags(num_vreg_flags)
 514     , _barrier_set(BarrierSet::barrier_set()->barrier_set_c1()) {
 515   }
 516 
 517   // for virtual registers, maps them back to Phi's or Local's
 518   Instruction* instruction_for_opr(LIR_Opr opr);
 519   Instruction* instruction_for_vreg(int reg_num);
 520 
 521   void set_vreg_flag   (int vreg_num, VregFlag f);
 522   bool is_vreg_flag_set(int vreg_num, VregFlag f);
 523   void set_vreg_flag   (LIR_Opr opr,  VregFlag f) { set_vreg_flag(opr->vreg_number(), f); }
 524   bool is_vreg_flag_set(LIR_Opr opr,  VregFlag f) { return is_vreg_flag_set(opr->vreg_number(), f); }
 525 
 526   // statics
 527   static LIR_Opr exceptionOopOpr();
 528   static LIR_Opr exceptionPcOpr();
 529   static LIR_Opr divInOpr();
 530   static LIR_Opr divOutOpr();
 531   static LIR_Opr remOutOpr();
 532 #ifdef S390
 533   // On S390 we can do ldiv, lrem without RT call.
 534   static LIR_Opr ldivInOpr();
 535   static LIR_Opr ldivOutOpr();
 536   static LIR_Opr lremOutOpr();
 537 #endif
 538   static LIR_Opr shiftCountOpr();
 539   LIR_Opr syncLockOpr();
 540   LIR_Opr syncTempOpr();
 541   LIR_Opr atomicLockOpr();
 542 
 543   // returns a register suitable for saving the thread in a
 544   // call_runtime_leaf if one is needed.
 545   LIR_Opr getThreadTemp();
 546 
 547   // visitor functionality
 548   virtual void do_Phi            (Phi*             x);
 549   virtual void do_Local          (Local*           x);
 550   virtual void do_Constant       (Constant*        x);
 551   virtual void do_LoadField      (LoadField*       x);
 552   virtual void do_StoreField     (StoreField*      x);
 553   virtual void do_ArrayLength    (ArrayLength*     x);
 554   virtual void do_LoadIndexed    (LoadIndexed*     x);
 555   virtual void do_StoreIndexed   (StoreIndexed*    x);
 556   virtual void do_NegateOp       (NegateOp*        x);
 557   virtual void do_ArithmeticOp   (ArithmeticOp*    x);
 558   virtual void do_ShiftOp        (ShiftOp*         x);
 559   virtual void do_LogicOp        (LogicOp*         x);
 560   virtual void do_CompareOp      (CompareOp*       x);
 561   virtual void do_IfOp           (IfOp*            x);
 562   virtual void do_Convert        (Convert*         x);
 563   virtual void do_NullCheck      (NullCheck*       x);
 564   virtual void do_TypeCast       (TypeCast*        x);
 565   virtual void do_Invoke         (Invoke*          x);
 566   virtual void do_NewInstance    (NewInstance*     x);
 567   virtual void do_NewTypeArray   (NewTypeArray*    x);
 568   virtual void do_NewObjectArray (NewObjectArray*  x);
 569   virtual void do_NewMultiArray  (NewMultiArray*   x);
 570   virtual void do_CheckCast      (CheckCast*       x);
 571   virtual void do_InstanceOf     (InstanceOf*      x);
 572   virtual void do_MonitorEnter   (MonitorEnter*    x);
 573   virtual void do_MonitorExit    (MonitorExit*     x);
 574   virtual void do_Intrinsic      (Intrinsic*       x);
 575   virtual void do_BlockBegin     (BlockBegin*      x);
 576   virtual void do_Goto           (Goto*            x);
 577   virtual void do_If             (If*              x);
 578   virtual void do_IfInstanceOf   (IfInstanceOf*    x);
 579   virtual void do_TableSwitch    (TableSwitch*     x);
 580   virtual void do_LookupSwitch   (LookupSwitch*    x);
 581   virtual void do_Return         (Return*          x);
 582   virtual void do_Throw          (Throw*           x);
 583   virtual void do_Base           (Base*            x);
 584   virtual void do_OsrEntry       (OsrEntry*        x);
 585   virtual void do_ExceptionObject(ExceptionObject* x);
 586   virtual void do_RoundFP        (RoundFP*         x);
 587   virtual void do_UnsafeGetRaw   (UnsafeGetRaw*    x);
 588   virtual void do_UnsafePutRaw   (UnsafePutRaw*    x);
 589   virtual void do_UnsafeGetObject(UnsafeGetObject* x);
 590   virtual void do_UnsafePutObject(UnsafePutObject* x);
 591   virtual void do_UnsafeGetAndSetObject(UnsafeGetAndSetObject* x);
 592   virtual void do_ProfileCall    (ProfileCall*     x);
 593   virtual void do_ProfileReturnType (ProfileReturnType* x);
 594   virtual void do_ProfileInvoke  (ProfileInvoke*   x);
 595   virtual void do_RuntimeCall    (RuntimeCall*     x);
 596   virtual void do_MemBar         (MemBar*          x);
 597   virtual void do_RangeCheckPredicate(RangeCheckPredicate* x);
 598 #ifdef ASSERT
 599   virtual void do_Assert         (Assert*          x);
 600 #endif
 601 
 602 #ifdef C1_LIRGENERATOR_MD_HPP
 603 #include C1_LIRGENERATOR_MD_HPP
 604 #endif
 605 };
 606 
 607 
 608 class LIRItem: public CompilationResourceObj {
 609  private:
 610   Value         _value;
 611   LIRGenerator* _gen;
 612   LIR_Opr       _result;
 613   bool          _destroys_register;
 614   LIR_Opr       _new_result;
 615 
 616   LIRGenerator* gen() const { return _gen; }
 617 
 618  public:
 619   LIRItem(Value value, LIRGenerator* gen) {
 620     _destroys_register = false;
 621     _gen = gen;
 622     set_instruction(value);
 623   }
 624 
 625   LIRItem(LIRGenerator* gen) {
 626     _destroys_register = false;
 627     _gen = gen;
 628     _result = LIR_OprFact::illegalOpr;
 629     set_instruction(NULL);
 630   }
 631 
 632   void set_instruction(Value value) {
 633     _value = value;
 634     _result = LIR_OprFact::illegalOpr;
 635     if (_value != NULL) {
 636       _gen->walk(_value);
 637       _result = _value->operand();
 638     }
 639     _new_result = LIR_OprFact::illegalOpr;
 640   }
 641 
 642   Value value() const          { return _value;          }
 643   ValueType* type() const      { return value()->type(); }
 644   LIR_Opr result()             {
 645     assert(!_destroys_register || (!_result->is_register() || _result->is_virtual()),
 646            "shouldn't use set_destroys_register with physical regsiters");
 647     if (_destroys_register && _result->is_register()) {
 648       if (_new_result->is_illegal()) {
 649         _new_result = _gen->new_register(type());
 650         gen()->lir()->move(_result, _new_result);
 651       }
 652       return _new_result;
 653     } else {
 654       return _result;
 655     }
 656     return _result;
 657   }
 658 
 659   void set_result(LIR_Opr opr);
 660 
 661   void load_item();
 662   void load_byte_item();
 663   void load_nonconstant(S390_ONLY(int bits = 20));
 664   // load any values which can't be expressed as part of a single store instruction
 665   void load_for_store(BasicType store_type);
 666   void load_item_force(LIR_Opr reg);
 667 
 668   void dont_load_item() {
 669     // do nothing
 670   }
 671 
 672   void set_destroys_register() {
 673     _destroys_register = true;
 674   }
 675 
 676   bool is_constant() const { return value()->as_Constant() != NULL; }
 677   bool is_stack()          { return result()->is_stack(); }
 678   bool is_register()       { return result()->is_register(); }
 679 
 680   ciObject* get_jobject_constant() const;
 681   jint      get_jint_constant() const;
 682   jlong     get_jlong_constant() const;
 683   jfloat    get_jfloat_constant() const;
 684   jdouble   get_jdouble_constant() const;
 685   jint      get_address_constant() const;
 686 };
 687 
 688 #endif // SHARE_C1_C1_LIRGENERATOR_HPP