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1 /*
2  * Copyright (C) 2014 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_QUICK_RESOURCE_MASK_H_
18 #define ART_COMPILER_DEX_QUICK_RESOURCE_MASK_H_
19 
20 #include <stdint.h>
21 
22 #include "base/logging.h"
23 #include "base/value_object.h"
24 #include "dex/reg_storage.h"
25 
26 namespace art {
27 
28 class ArenaAllocator;
29 
30 /**
31  * @brief Resource mask for LIR insn uses or defs.
32  * @detail Def/Use mask used for checking dependencies between LIR insns in local
33  * optimizations such as load hoisting.
34  */
35 class ResourceMask {
36  private:
ResourceMask(uint64_t mask1,uint64_t mask2)37   constexpr ResourceMask(uint64_t mask1, uint64_t mask2)
38       : masks_{ mask1, mask2 } {  // NOLINT
39   }
40 
41  public:
42   /*
43    * Def/Use encoding in 128-bit use_mask/def_mask.  Low positions used for target-specific
44    * registers (and typically use the register number as the position).  High positions
45    * reserved for common and abstract resources.
46    */
47   enum ResourceBit {
48     kMustNotAlias = 127,
49     kHeapRef = 126,         // Default memory reference type.
50     kLiteral = 125,         // Literal pool memory reference.
51     kDalvikReg = 124,       // Dalvik v_reg memory reference.
52     kFPStatus = 123,
53     kCCode = 122,
54     kLowestCommonResource = kCCode,
55     kHighestCommonResource = kMustNotAlias
56   };
57 
58   // Default-constructible.
ResourceMask()59   constexpr ResourceMask()
60     : masks_ { 0u, 0u } {
61   }
62 
63   // Copy-constructible and copyable.
64   ResourceMask(const ResourceMask& other) = default;
65   ResourceMask& operator=(const ResourceMask& other) = default;
66 
67   // Comparable by content.
68   bool operator==(const ResourceMask& other) {
69     return masks_[0] == other.masks_[0] && masks_[1] == other.masks_[1];
70   }
71 
RawMask(uint64_t mask1,uint64_t mask2)72   static constexpr ResourceMask RawMask(uint64_t mask1, uint64_t mask2) {
73     return ResourceMask(mask1, mask2);
74   }
75 
Bit(size_t bit)76   static constexpr ResourceMask Bit(size_t bit) {
77     return ResourceMask(bit >= 64u ? 0u : UINT64_C(1) << bit,
78                         bit >= 64u ? UINT64_C(1) << (bit - 64u) : 0u);
79   }
80 
81   // Two consecutive bits. The start_bit must be even.
TwoBits(size_t start_bit)82   static constexpr ResourceMask TwoBits(size_t start_bit) {
83     return
84         DCHECK_CONSTEXPR((start_bit & 1u) == 0u, << start_bit << " isn't even", Bit(0))
85         ResourceMask(start_bit >= 64u ? 0u : UINT64_C(3) << start_bit,
86                      start_bit >= 64u ? UINT64_C(3) << (start_bit - 64u) : 0u);
87   }
88 
NoBits()89   static constexpr ResourceMask NoBits() {
90     return ResourceMask(UINT64_C(0), UINT64_C(0));
91   }
92 
AllBits()93   static constexpr ResourceMask AllBits() {
94     return ResourceMask(~UINT64_C(0), ~UINT64_C(0));
95   }
96 
Union(const ResourceMask & other)97   constexpr ResourceMask Union(const ResourceMask& other) const {
98     return ResourceMask(masks_[0] | other.masks_[0], masks_[1] | other.masks_[1]);
99   }
100 
Intersection(const ResourceMask & other)101   constexpr ResourceMask Intersection(const ResourceMask& other) const {
102     return ResourceMask(masks_[0] & other.masks_[0], masks_[1] & other.masks_[1]);
103   }
104 
Without(const ResourceMask & other)105   constexpr ResourceMask Without(const ResourceMask& other) const {
106     return ResourceMask(masks_[0] & ~other.masks_[0], masks_[1] & ~other.masks_[1]);
107   }
108 
Equals(const ResourceMask & other)109   constexpr bool Equals(const ResourceMask& other) const {
110     return masks_[0] == other.masks_[0] && masks_[1] == other.masks_[1];
111   }
112 
Intersects(const ResourceMask & other)113   constexpr bool Intersects(const ResourceMask& other) const {
114     return (masks_[0] & other.masks_[0]) != 0u || (masks_[1] & other.masks_[1]) != 0u;
115   }
116 
117   void SetBit(size_t bit);
118 
HasBit(size_t bit)119   constexpr bool HasBit(size_t bit) const {
120     return (masks_[bit / 64u] & (UINT64_C(1) << (bit & 63u))) != 0u;
121   }
122 
SetBits(const ResourceMask & other)123   ResourceMask& SetBits(const ResourceMask& other) {
124     masks_[0] |= other.masks_[0];
125     masks_[1] |= other.masks_[1];
126     return *this;
127   }
128 
ClearBits(const ResourceMask & other)129   ResourceMask& ClearBits(const ResourceMask& other) {
130     masks_[0] &= ~other.masks_[0];
131     masks_[1] &= ~other.masks_[1];
132     return *this;
133   }
134 
135  private:
136   uint64_t masks_[2];
137 
138   friend class ResourceMaskCache;
139 };
140 std::ostream& operator<<(std::ostream& os, const ResourceMask::ResourceBit& rhs);
141 
SetBit(size_t bit)142 inline void ResourceMask::SetBit(size_t bit) {
143   DCHECK_LE(bit, kHighestCommonResource);
144   masks_[bit / 64u] |= UINT64_C(1) << (bit & 63u);
145 }
146 
147 constexpr ResourceMask kEncodeNone = ResourceMask::NoBits();
148 constexpr ResourceMask kEncodeAll = ResourceMask::AllBits();
149 constexpr ResourceMask kEncodeHeapRef = ResourceMask::Bit(ResourceMask::kHeapRef);
150 constexpr ResourceMask kEncodeLiteral = ResourceMask::Bit(ResourceMask::kLiteral);
151 constexpr ResourceMask kEncodeDalvikReg = ResourceMask::Bit(ResourceMask::kDalvikReg);
152 constexpr ResourceMask kEncodeMem = kEncodeLiteral.Union(kEncodeDalvikReg).Union(
153     kEncodeHeapRef).Union(ResourceMask::Bit(ResourceMask::kMustNotAlias));
154 
155 class ResourceMaskCache {
156  public:
ResourceMaskCache(ArenaAllocator * allocator)157   explicit ResourceMaskCache(ArenaAllocator* allocator)
158       : allocator_(allocator) {
159   }
160 
161   const ResourceMask* GetMask(const ResourceMask& mask);
162 
163  private:
164   ArenaAllocator* allocator_;
165 };
166 
167 }  // namespace art
168 
169 #endif  // ART_COMPILER_DEX_QUICK_RESOURCE_MASK_H_
170