1 /*
2  * Copyright (C) 2015 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_LIBELFFILE_DWARF_WRITER_H_
18 #define ART_LIBELFFILE_DWARF_WRITER_H_
19 
20 #include <type_traits>
21 #include <vector>
22 
23 #include <android-base/logging.h>
24 
25 #include "base/bit_utils.h"
26 #include "base/leb128.h"
27 
28 namespace art {
29 namespace dwarf {
30 
31 // The base class for all DWARF writers.
32 template <typename Vector = std::vector<uint8_t>>
33 class Writer {
34   static_assert(std::is_same<typename Vector::value_type, uint8_t>::value, "Invalid value type");
35 
36  public:
PushUint8(int value)37   void PushUint8(int value) {
38     DCHECK_GE(value, 0);
39     DCHECK_LE(value, UINT8_MAX);
40     data_->push_back(value & 0xff);
41   }
42 
PushUint16(int value)43   void PushUint16(int value) {
44     DCHECK_GE(value, 0);
45     DCHECK_LE(value, UINT16_MAX);
46     data_->push_back((value >> 0) & 0xff);
47     data_->push_back((value >> 8) & 0xff);
48   }
49 
PushUint32(uint32_t value)50   void PushUint32(uint32_t value) {
51     data_->push_back((value >> 0) & 0xff);
52     data_->push_back((value >> 8) & 0xff);
53     data_->push_back((value >> 16) & 0xff);
54     data_->push_back((value >> 24) & 0xff);
55   }
56 
PushUint32(int value)57   void PushUint32(int value) {
58     DCHECK_GE(value, 0);
59     PushUint32(static_cast<uint32_t>(value));
60   }
61 
PushUint32(uint64_t value)62   void PushUint32(uint64_t value) {
63     DCHECK_LE(value, UINT32_MAX);
64     PushUint32(static_cast<uint32_t>(value));
65   }
66 
PushUint64(uint64_t value)67   void PushUint64(uint64_t value) {
68     data_->push_back((value >> 0) & 0xff);
69     data_->push_back((value >> 8) & 0xff);
70     data_->push_back((value >> 16) & 0xff);
71     data_->push_back((value >> 24) & 0xff);
72     data_->push_back((value >> 32) & 0xff);
73     data_->push_back((value >> 40) & 0xff);
74     data_->push_back((value >> 48) & 0xff);
75     data_->push_back((value >> 56) & 0xff);
76   }
77 
PushInt8(int value)78   void PushInt8(int value) {
79     DCHECK_GE(value, INT8_MIN);
80     DCHECK_LE(value, INT8_MAX);
81     PushUint8(static_cast<uint8_t>(value));
82   }
83 
PushInt16(int value)84   void PushInt16(int value) {
85     DCHECK_GE(value, INT16_MIN);
86     DCHECK_LE(value, INT16_MAX);
87     PushUint16(static_cast<uint16_t>(value));
88   }
89 
PushInt32(int value)90   void PushInt32(int value) {
91     PushUint32(static_cast<uint32_t>(value));
92   }
93 
PushInt64(int64_t value)94   void PushInt64(int64_t value) {
95     PushUint64(static_cast<uint64_t>(value));
96   }
97 
98   // Variable-length encoders.
99 
PushUleb128(uint32_t value)100   void PushUleb128(uint32_t value) {
101     EncodeUnsignedLeb128(data_, value);
102   }
103 
PushUleb128(int value)104   void PushUleb128(int value) {
105     DCHECK_GE(value, 0);
106     EncodeUnsignedLeb128(data_, value);
107   }
108 
PushSleb128(int value)109   void PushSleb128(int value) {
110     EncodeSignedLeb128(data_, value);
111   }
112 
113   // Miscellaneous functions.
114 
PushString(const char * value)115   void PushString(const char* value) {
116     data_->insert(data_->end(), value, value + strlen(value) + 1);
117   }
118 
PushData(const uint8_t * ptr,size_t num_bytes)119   void PushData(const uint8_t* ptr, size_t num_bytes) {
120     data_->insert(data_->end(), ptr, ptr + num_bytes);
121   }
122 
PushData(const char * ptr,size_t num_bytes)123   void PushData(const char* ptr, size_t num_bytes) {
124     data_->insert(data_->end(), ptr, ptr + num_bytes);
125   }
126 
PushData(const Vector * buffer)127   void PushData(const Vector* buffer) {
128     data_->insert(data_->end(), buffer->begin(), buffer->end());
129   }
130 
UpdateUint32(size_t offset,uint32_t value)131   void UpdateUint32(size_t offset, uint32_t value) {
132     DCHECK_LT(offset + 3, data_->size());
133     (*data_)[offset + 0] = (value >> 0) & 0xFF;
134     (*data_)[offset + 1] = (value >> 8) & 0xFF;
135     (*data_)[offset + 2] = (value >> 16) & 0xFF;
136     (*data_)[offset + 3] = (value >> 24) & 0xFF;
137   }
138 
UpdateUint64(size_t offset,uint64_t value)139   void UpdateUint64(size_t offset, uint64_t value) {
140     DCHECK_LT(offset + 7, data_->size());
141     (*data_)[offset + 0] = (value >> 0) & 0xFF;
142     (*data_)[offset + 1] = (value >> 8) & 0xFF;
143     (*data_)[offset + 2] = (value >> 16) & 0xFF;
144     (*data_)[offset + 3] = (value >> 24) & 0xFF;
145     (*data_)[offset + 4] = (value >> 32) & 0xFF;
146     (*data_)[offset + 5] = (value >> 40) & 0xFF;
147     (*data_)[offset + 6] = (value >> 48) & 0xFF;
148     (*data_)[offset + 7] = (value >> 56) & 0xFF;
149   }
150 
UpdateUleb128(size_t offset,uint32_t value)151   void UpdateUleb128(size_t offset, uint32_t value) {
152     DCHECK_LE(offset + UnsignedLeb128Size(value), data_->size());
153     UpdateUnsignedLeb128(data_->data() + offset, value);
154   }
155 
Pop()156   void Pop() {
157     return data_->pop_back();
158   }
159 
Pad(int alignment)160   void Pad(int alignment) {
161     DCHECK_NE(alignment, 0);
162     data_->resize(RoundUp(data_->size(), alignment), 0);
163   }
164 
data()165   const Vector* data() const {
166     return data_;
167   }
168 
size()169   size_t size() const {
170     return data_->size();
171   }
172 
Writer(Vector * buffer)173   explicit Writer(Vector* buffer) : data_(buffer) { }
174 
175  private:
176   Vector* const data_;
177 
178   DISALLOW_COPY_AND_ASSIGN(Writer);
179 };
180 
181 }  // namespace dwarf
182 }  // namespace art
183 
184 #endif  // ART_LIBELFFILE_DWARF_WRITER_H_
185