1 /*

     2  * Copyright (c) 2012, 2016, 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_VM_C1_C1_RANGECHECKELIMINATION_HPP

    26 #define SHARE_VM_C1_C1_RANGECHECKELIMINATION_HPP

    27 

    28 #include "c1/c1_Instruction.hpp"

    29 

    30 // Base class for range check elimination

    31 class RangeCheckElimination : AllStatic {

    32 public:

    33   static void eliminate(IR *ir);

    34 };

    35 

    36 // Implementation

    37 class RangeCheckEliminator VALUE_OBJ_CLASS_SPEC {

    38 private:

    39   int _number_of_instructions;

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

    41   IR *_ir;

    42 

    43   typedef GrowableArray<BlockBegin*> BlockBeginList;

    44   typedef GrowableArray<int> IntegerStack;

    45 

    46   class Verification : public BlockClosure {

    47   // RangeCheckEliminator::Verification should never get instatiated on the heap.

    48   private:

    49     void* operator new(size_t size) throw();

    50     void* operator new[](size_t size) throw();

    51     void operator delete(void* p) { ShouldNotReachHere(); }

    52     void operator delete[](void* p) { ShouldNotReachHere(); }

    53 

    54     IR *_ir;

    55     boolArray _used;

    56     BlockBeginList _current;

    57     BlockBeginList _successors;

    58 

    59   public:

    60     Verification(IR *ir);

    61     virtual void block_do(BlockBegin *block);

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

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

    64   };

    65 

    66 public:

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

    68   // constant and x another instruction

    69   class Bound : public CompilationResourceObj {

    70   private:

    71     int _upper;

    72     Value _upper_instr;

    73     int _lower;

    74     Value _lower_instr;

    75 

    76   public:

    77     Bound();

    78     Bound(Value v);

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

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

    81     ~Bound();

    82 

    83 #ifdef ASSERT

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

    85 #endif

    86     int upper();

    87     Value upper_instr();

    88     int lower();

    89     Value lower_instr();

    90     void print();

    91     bool check_no_overflow(int const_value);

    92     void or_op(Bound *b);

    93     void and_op(Bound *b);

    94     bool has_upper();

    95     bool has_lower();

    96     void set_upper(int upper, Value upper_instr);

    97     void set_lower(int lower, Value lower_instr);

    98     bool is_smaller(Bound *b);

    99     void remove_upper();

   100     void remove_lower();

   101     void add_constant(int value);

   102     Bound *copy();

   103 

   104   private:

   105     void init();

   106   };

   107 

   108 

   109   class Visitor : public InstructionVisitor {

   110   private:

   111     Bound *_bound;

   112     RangeCheckEliminator *_rce;

   113 

   114   public:

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

   116     Bound *bound() const { return _bound; }

   117     void clear_bound() { _bound = NULL; }

   118 

   119   protected:

   120     // visitor functions

   121     void do_Constant       (Constant*        x);

   122     void do_IfOp           (IfOp*            x);

   123     void do_LogicOp        (LogicOp*         x);

   124     void do_ArithmeticOp   (ArithmeticOp*    x);

   125     void do_Phi            (Phi*             x);

   126 

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

   172 #ifdef ASSERT

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

   174 #endif

   175   };

   176 

   177 #ifdef ASSERT

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

   179 #endif

   180 

   181   typedef GrowableArray<Bound*> BoundStack;

   182   typedef GrowableArray<BoundStack*> BoundMap;

   183   typedef GrowableArray<AccessIndexed*> AccessIndexedList;

   184   typedef GrowableArray<Instruction*> InstructionList;

   185 

   186   class AccessIndexedInfo : public CompilationResourceObj  {

   187   public:

   188     AccessIndexedList *_list;

   189     int _min;

   190     int _max;

   191   };

   192 

   193   typedef GrowableArray<AccessIndexedInfo*> AccessIndexedInfoArray;

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

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

   196   Visitor _visitor;

   197 

   198 public:

   199   RangeCheckEliminator(IR *ir);

   200 

   201   IR *ir() const { return _ir; }

   202 

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

   204   bool set_process_block_flags(BlockBegin *block);

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

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

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

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

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

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

   211 

   212   // update/access current bound

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

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

   215   Bound *get_bound(Value v);

   216 

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

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

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

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

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

   222 

   223   // helper functions to work with predicates

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

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

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

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

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

   229 

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

   231                              Instruction *length_instruction, Instruction *lower_instr, int lower,

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

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

   234                                 Instruction *length_instr, Instruction *lower_instr,

   235                                 int lower, Instruction *upper_instr, int upper);

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

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

   238 

   239   void dump_condition_stack(BlockBegin *cur_block);

   240   static void print_statistics();

   241 };

   242 

   243 #endif // SHARE_VM_C1_C1_RANGECHECKELIMINATION_HPP