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      1 /*
      2  * Copyright (C) 2012 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #ifndef ART_COMPILER_DEX_LOCAL_VALUE_NUMBERING_H_
     18 #define ART_COMPILER_DEX_LOCAL_VALUE_NUMBERING_H_
     19 
     20 #include "compiler_internals.h"
     21 
     22 #define NO_VALUE 0xffff
     23 #define ARRAY_REF 0xfffe
     24 
     25 namespace art {
     26 
     27 // Key is s_reg, value is value name.
     28 typedef SafeMap<uint16_t, uint16_t> SregValueMap;
     29 // Key is concatenation of quad, value is value name.
     30 typedef SafeMap<uint64_t, uint16_t> ValueMap;
     31 // Key represents a memory address, value is generation.
     32 typedef SafeMap<uint32_t, uint16_t> MemoryVersionMap;
     33 
     34 class LocalValueNumbering {
     35  public:
     36   explicit LocalValueNumbering(CompilationUnit* cu) : cu_(cu) {}
     37 
     38   static uint64_t BuildKey(uint16_t op, uint16_t operand1, uint16_t operand2, uint16_t modifier) {
     39     return (static_cast<uint64_t>(op) << 48 | static_cast<uint64_t>(operand1) << 32 |
     40             static_cast<uint64_t>(operand2) << 16 | static_cast<uint64_t>(modifier));
     41   };
     42 
     43   uint16_t LookupValue(uint16_t op, uint16_t operand1, uint16_t operand2, uint16_t modifier) {
     44     uint16_t res;
     45     uint64_t key = BuildKey(op, operand1, operand2, modifier);
     46     ValueMap::iterator it = value_map_.find(key);
     47     if (it != value_map_.end()) {
     48       res = it->second;
     49     } else {
     50       res = value_map_.size() + 1;
     51       value_map_.Put(key, res);
     52     }
     53     return res;
     54   };
     55 
     56   bool ValueExists(uint16_t op, uint16_t operand1, uint16_t operand2, uint16_t modifier) const {
     57     uint64_t key = BuildKey(op, operand1, operand2, modifier);
     58     ValueMap::const_iterator it = value_map_.find(key);
     59     return (it != value_map_.end());
     60   };
     61 
     62   uint16_t GetMemoryVersion(uint16_t base, uint16_t field) {
     63     uint32_t key = (base << 16) | field;
     64     uint16_t res;
     65     MemoryVersionMap::iterator it = memory_version_map_.find(key);
     66     if (it == memory_version_map_.end()) {
     67       res = 0;
     68       memory_version_map_.Put(key, res);
     69     } else {
     70       res = it->second;
     71     }
     72     return res;
     73   };
     74 
     75   void AdvanceMemoryVersion(uint16_t base, uint16_t field) {
     76     uint32_t key = (base << 16) | field;
     77     MemoryVersionMap::iterator it = memory_version_map_.find(key);
     78     if (it == memory_version_map_.end()) {
     79       memory_version_map_.Put(key, 0);
     80     } else {
     81       it->second++;
     82     }
     83   };
     84 
     85   void SetOperandValue(uint16_t s_reg, uint16_t value) {
     86     SregValueMap::iterator it = sreg_value_map_.find(s_reg);
     87     if (it != sreg_value_map_.end()) {
     88       DCHECK_EQ(it->second, value);
     89     } else {
     90       sreg_value_map_.Put(s_reg, value);
     91     }
     92   };
     93 
     94   uint16_t GetOperandValue(int s_reg) {
     95     uint16_t res = NO_VALUE;
     96     SregValueMap::iterator it = sreg_value_map_.find(s_reg);
     97     if (it != sreg_value_map_.end()) {
     98       res = it->second;
     99     } else {
    100       // First use
    101       res = LookupValue(NO_VALUE, s_reg, NO_VALUE, NO_VALUE);
    102       sreg_value_map_.Put(s_reg, res);
    103     }
    104     return res;
    105   };
    106 
    107   void SetOperandValueWide(uint16_t s_reg, uint16_t value) {
    108     SregValueMap::iterator it = sreg_wide_value_map_.find(s_reg);
    109     if (it != sreg_wide_value_map_.end()) {
    110       DCHECK_EQ(it->second, value);
    111     } else {
    112       sreg_wide_value_map_.Put(s_reg, value);
    113     }
    114   };
    115 
    116   uint16_t GetOperandValueWide(int s_reg) {
    117     uint16_t res = NO_VALUE;
    118     SregValueMap::iterator it = sreg_wide_value_map_.find(s_reg);
    119     if (it != sreg_wide_value_map_.end()) {
    120       res = it->second;
    121     } else {
    122       // First use
    123       res = LookupValue(NO_VALUE, s_reg, NO_VALUE, NO_VALUE);
    124       sreg_wide_value_map_.Put(s_reg, res);
    125     }
    126     return res;
    127   };
    128 
    129   uint16_t GetValueNumber(MIR* mir);
    130 
    131  private:
    132   CompilationUnit* const cu_;
    133   SregValueMap sreg_value_map_;
    134   SregValueMap sreg_wide_value_map_;
    135   ValueMap value_map_;
    136   MemoryVersionMap memory_version_map_;
    137   std::set<uint16_t> null_checked_;
    138 };
    139 
    140 }  // namespace art
    141 
    142 #endif  // ART_COMPILER_DEX_LOCAL_VALUE_NUMBERING_H_
    143