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 /*

  * Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

  * or visit www.oracle.com if you need additional information or have any

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 #ifndef SHARE_VM_C1_C1_RANGECHECKELIMINATION_HPP

 #define SHARE_VM_C1_C1_RANGECHECKELIMINATION_HPP

 #include "c1/c1_Instruction.hpp"

 // Base class for range check elimination

 class RangeCheckElimination : AllStatic {

 public:

   static void eliminate(IR *ir);

 };

 // Implementation

 class RangeCheckEliminator VALUE_OBJ_CLASS_SPEC {

 private:

   int _number_of_instructions;

   bool _optimistic; // Insert predicates and deoptimize when they fail

   IR *_ir;

   define_array(BlockBeginArray, BlockBegin*)

   define_stack(BlockBeginList, BlockBeginArray)

   define_stack(IntegerStack, intArray)

   define_array(IntegerMap, IntegerStack*)

   class Verification : public _ValueObj /*VALUE_OBJ_CLASS_SPEC*/, public BlockClosure {

   private:

     IR *_ir;

     boolArray _used;

     BlockBeginList _current;

     BlockBeginList _successors;

   public:

     Verification(IR *ir);

     virtual void block_do(BlockBegin *block);

     bool can_reach(BlockBegin *start, BlockBegin *end, BlockBegin *dont_use = NULL);

     bool dominates(BlockBegin *dominator, BlockBegin *block);

   };

 public:

   // Bounds for an instruction in the form x + c which c integer

   // constant and x another instruction

   class Bound : public CompilationResourceObj {

   private:

     int _upper;

     Value _upper_instr;

     int _lower;

     Value _lower_instr;

   public:

     Bound();

     Bound(Value v);

     Bound(Instruction::Condition cond, Value v, int constant = 0);

     Bound(int lower, Value lower_instr, int upper, Value upper_instr);

     ~Bound();

 #ifdef ASSERT

     void add_assertion(Instruction *instruction, Instruction *position, int i, Value instr, Instruction::Condition cond);

 #endif

     int upper();

     Value upper_instr();

     int lower();

     Value lower_instr();

     void print();

     bool check_no_overflow(int const_value);

     void or_op(Bound *b);

     void and_op(Bound *b);

     bool has_upper();

     bool has_lower();

     void set_upper(int upper, Value upper_instr);

     void set_lower(int lower, Value lower_instr);

     bool is_smaller(Bound *b);

     void remove_upper();

     void remove_lower();

     void add_constant(int value);

     Bound *copy();

   private:

     void init();

   };

   class Visitor : public InstructionVisitor {

   private:

     Bound *_bound;

     RangeCheckEliminator *_rce;

   public:

     void set_range_check_eliminator(RangeCheckEliminator *rce) { _rce = rce; }

     Bound *bound() const { return _bound; }

     void clear_bound() { _bound = NULL; }

   protected:

     // visitor functions

     void do_Constant       (Constant*        x);

     void do_IfOp           (IfOp*            x);

     void do_LogicOp        (LogicOp*         x);

     void do_ArithmeticOp   (ArithmeticOp*    x);

     void do_Phi            (Phi*             x);

     void do_StoreField     (StoreField*      x) { /* nothing to do */ };

     void do_StoreIndexed   (StoreIndexed*    x) { /* nothing to do */ };

     void do_MonitorEnter   (MonitorEnter*    x) { /* nothing to do */ };

     void do_MonitorExit    (MonitorExit*     x) { /* nothing to do */ };

     void do_Invoke         (Invoke*          x) { /* nothing to do */ };

     void do_UnsafePutRaw   (UnsafePutRaw*    x) { /* nothing to do */ };

     void do_UnsafePutObject(UnsafePutObject* x) { /* nothing to do */ };

     void do_Intrinsic      (Intrinsic*       x) { /* nothing to do */ };

     void do_Local          (Local*           x) { /* nothing to do */ };

     void do_LoadField      (LoadField*       x) { /* nothing to do */ };

     void do_ArrayLength    (ArrayLength*     x) { /* nothing to do */ };

     void do_LoadIndexed    (LoadIndexed*     x) { /* nothing to do */ };

     void do_NegateOp       (NegateOp*        x) { /* nothing to do */ };

     void do_ShiftOp        (ShiftOp*         x) { /* nothing to do */ };

     void do_CompareOp      (CompareOp*       x) { /* nothing to do */ };

     void do_Convert        (Convert*         x) { /* nothing to do */ };

     void do_NullCheck      (NullCheck*       x) { /* nothing to do */ };

     void do_TypeCast       (TypeCast*        x) { /* nothing to do */ };

     void do_NewInstance    (NewInstance*     x) { /* nothing to do */ };

     void do_NewTypeArray   (NewTypeArray*    x) { /* nothing to do */ };

     void do_NewObjectArray (NewObjectArray*  x) { /* nothing to do */ };

     void do_NewMultiArray  (NewMultiArray*   x) { /* nothing to do */ };

     void do_CheckCast      (CheckCast*       x) { /* nothing to do */ };

     void do_InstanceOf     (InstanceOf*      x) { /* nothing to do */ };

     void do_BlockBegin     (BlockBegin*      x) { /* nothing to do */ };

     void do_Goto           (Goto*            x) { /* nothing to do */ };

     void do_If             (If*              x) { /* nothing to do */ };

     void do_IfInstanceOf   (IfInstanceOf*    x) { /* nothing to do */ };

     void do_TableSwitch    (TableSwitch*     x) { /* nothing to do */ };

     void do_LookupSwitch   (LookupSwitch*    x) { /* nothing to do */ };

     void do_Return         (Return*          x) { /* nothing to do */ };

     void do_Throw          (Throw*           x) { /* nothing to do */ };

     void do_Base           (Base*            x) { /* nothing to do */ };

     void do_OsrEntry       (OsrEntry*        x) { /* nothing to do */ };

     void do_ExceptionObject(ExceptionObject* x) { /* nothing to do */ };

     void do_RoundFP        (RoundFP*         x) { /* nothing to do */ };

     void do_UnsafeGetRaw   (UnsafeGetRaw*    x) { /* nothing to do */ };

     void do_UnsafeGetObject(UnsafeGetObject* x) { /* nothing to do */ };

     void do_UnsafeGetAndSetObject(UnsafeGetAndSetObject* x) { /* nothing to do */ };

     void do_UnsafePrefetchRead (UnsafePrefetchRead*  x) { /* nothing to do */ };

     void do_UnsafePrefetchWrite(UnsafePrefetchWrite* x) { /* nothing to do */ };

     void do_ProfileCall    (ProfileCall*     x) { /* nothing to do */ };

     void do_ProfileReturnType (ProfileReturnType*  x) { /* nothing to do */ };

     void do_ProfileInvoke  (ProfileInvoke*   x) { /* nothing to do */ };

     void do_RuntimeCall    (RuntimeCall*     x) { /* nothing to do */ };

     void do_MemBar         (MemBar*          x) { /* nothing to do */ };

     void do_RangeCheckPredicate(RangeCheckPredicate* x) { /* nothing to do */ };

 #ifdef ASSERT

     void do_Assert         (Assert*          x) { /* nothing to do */ };

 #endif

   };

 #ifdef ASSERT

   void add_assertions(Bound *bound, Instruction *instruction, Instruction *position);

 #endif

   define_array(BoundArray, Bound *)

   define_stack(BoundStack, BoundArray)

   define_array(BoundMap, BoundStack *)

   define_array(AccessIndexedArray, AccessIndexed *)

   define_stack(AccessIndexedList, AccessIndexedArray)

   define_array(InstructionArray, Instruction *)

   define_stack(InstructionList, InstructionArray)

   class AccessIndexedInfo : public CompilationResourceObj  {

   public:

     AccessIndexedList *_list;

     int _min;

     int _max;

   };

   define_array(AccessIndexedInfoArray, AccessIndexedInfo *)

   BoundMap _bounds; // Mapping from Instruction's id to current bound

   AccessIndexedInfoArray _access_indexed_info; // Mapping from Instruction's id to AccessIndexedInfo for in block motion

   Visitor _visitor;

 public:

   RangeCheckEliminator(IR *ir);

   IR *ir() const { return _ir; }

   // Pass over the dominator tree to identify blocks where there's an oppportunity for optimization

   bool set_process_block_flags(BlockBegin *block);

   // The core of the optimization work: pass over the dominator tree

   // to propagate bound information, insert predicate out of loops,

   // eliminate bound checks when possible and perform in block motion

   void calc_bounds(BlockBegin *block, BlockBegin *loop_header);

   // reorder bound checks within a block in order to eliminate some of them

   void in_block_motion(BlockBegin *block, AccessIndexedList &accessIndexed, InstructionList &arrays);

   // update/access current bound

   void update_bound(IntegerStack &pushed, Value v, Instruction::Condition cond, Value value, int constant);

   void update_bound(IntegerStack &pushed, Value v, Bound *bound);

   Bound *get_bound(Value v);

   bool loop_invariant(BlockBegin *loop_header, Instruction *instruction);                                    // check for loop invariance

   void add_access_indexed_info(InstructionList &indices, int i, Value instruction, AccessIndexed *ai); // record indexed access for in block motion

   void remove_range_check(AccessIndexed *ai);                                                                // Mark this instructions as not needing a range check

   void add_if_condition(IntegerStack &pushed, Value x, Value y, Instruction::Condition condition);           // Update bound for an If

   bool in_array_bound(Bound *bound, Value array);                                                            // Check whether bound is known to fall within array

   // helper functions to work with predicates

   Instruction* insert_after(Instruction* insert_position, Instruction* instr, int bci);

   Instruction* predicate(Instruction* left, Instruction::Condition cond, Instruction* right, ValueStack* state, Instruction *insert_position, int bci=-1);

   Instruction* predicate_cmp_with_const(Instruction* instr, Instruction::Condition cond, int constant, ValueStack* state, Instruction *insert_position, int bci=1);

   Instruction* predicate_add(Instruction* left, int left_const, Instruction::Condition cond, Instruction* right, ValueStack* state, Instruction *insert_position, int bci=-1);

   Instruction* predicate_add_cmp_with_const(Instruction* left, int left_const, Instruction::Condition cond, int constant, ValueStack* state, Instruction *insert_position, int bci=-1);

   void insert_deoptimization(ValueStack *state, Instruction *insert_position, Instruction *array_instr,      // Add predicate

                              Instruction *length_instruction, Instruction *lower_instr, int lower,

                              Instruction *upper_instr, int upper, AccessIndexed *ai);

   bool is_ok_for_deoptimization(Instruction *insert_position, Instruction *array_instr,                      // Can we safely add a predicate?

                                 Instruction *length_instr, Instruction *lower_instr,

                                 int lower, Instruction *upper_instr, int upper);

   void process_if(IntegerStack &pushed, BlockBegin *block, If *cond);                                        // process If Instruction

   void process_access_indexed(BlockBegin *loop_header, BlockBegin *block, AccessIndexed *ai);                // process indexed access

   void dump_condition_stack(BlockBegin *cur_block);

   static void print_statistics();

 };

 #endif // SHARE_VM_C1_C1_RANGECHECKELIMINATION_HPP