1 /*
2  * Copyright (C) 2017 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_RUNTIME_ARCH_CODE_OFFSET_H_
18 #define ART_RUNTIME_ARCH_CODE_OFFSET_H_
19 
20 #include <iosfwd>
21 
22 #include "base/bit_utils.h"
23 #include "base/logging.h"
24 #include "instruction_set.h"
25 
26 namespace art {
27 
28 // CodeOffset is a holder for compressed code offsets. Since some architectures have alignment
29 // requirements it is possible to compress code offsets to reduce stack map sizes.
30 class CodeOffset {
31  public:
32   ALWAYS_INLINE static CodeOffset FromOffset(uint32_t offset, InstructionSet isa = kRuntimeISA) {
33     return CodeOffset(offset / GetInstructionSetInstructionAlignment(isa));
34   }
35 
FromCompressedOffset(uint32_t offset)36   ALWAYS_INLINE static CodeOffset FromCompressedOffset(uint32_t offset) {
37     return CodeOffset(offset);
38   }
39 
40   ALWAYS_INLINE uint32_t Uint32Value(InstructionSet isa = kRuntimeISA) const {
41     uint32_t decoded = value_ * GetInstructionSetInstructionAlignment(isa);
42     DCHECK_GE(decoded, value_) << "Integer overflow";
43     return decoded;
44   }
45 
46   // Return compressed internal value.
CompressedValue()47   ALWAYS_INLINE uint32_t CompressedValue() const {
48     return value_;
49   }
50 
51   ALWAYS_INLINE CodeOffset() = default;
52   ALWAYS_INLINE CodeOffset(const CodeOffset&) = default;
53   ALWAYS_INLINE CodeOffset& operator=(const CodeOffset&) = default;
54   ALWAYS_INLINE CodeOffset& operator=(CodeOffset&&) = default;
55 
56  private:
CodeOffset(uint32_t value)57   ALWAYS_INLINE explicit CodeOffset(uint32_t value) : value_(value) {}
58 
59   uint32_t value_ = 0u;
60 };
61 
62 inline bool operator==(const CodeOffset& a, const CodeOffset& b) {
63   return a.CompressedValue() == b.CompressedValue();
64 }
65 
66 inline bool operator!=(const CodeOffset& a, const CodeOffset& b) {
67   return !(a == b);
68 }
69 
70 inline bool operator<(const CodeOffset& a, const CodeOffset& b) {
71   return a.CompressedValue() < b.CompressedValue();
72 }
73 
74 inline bool operator<=(const CodeOffset& a, const CodeOffset& b) {
75   return a.CompressedValue() <= b.CompressedValue();
76 }
77 
78 inline bool operator>(const CodeOffset& a, const CodeOffset& b) {
79   return a.CompressedValue() > b.CompressedValue();
80 }
81 
82 inline bool operator>=(const CodeOffset& a, const CodeOffset& b) {
83   return a.CompressedValue() >= b.CompressedValue();
84 }
85 
86 inline std::ostream& operator<<(std::ostream& os, const CodeOffset& offset) {
87   return os << offset.Uint32Value();
88 }
89 
90 }  // namespace art
91 
92 #endif  // ART_RUNTIME_ARCH_CODE_OFFSET_H_
93