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_DEX2OAT_LINKER_ELF_WRITER_H_
18 #define ART_DEX2OAT_LINKER_ELF_WRITER_H_
19 
20 #include <stdint.h>
21 #include <cstddef>
22 #include <string>
23 #include <vector>
24 
25 #include "base/array_ref.h"
26 #include "base/macros.h"
27 #include "base/mutex.h"
28 #include "base/os.h"
29 #include "debug/debug_info.h"
30 
31 namespace art {
32 
33 class ElfFile;
34 
35 namespace debug {
36 struct MethodDebugInfo;
37 }  // namespace debug
38 
39 namespace linker {
40 
41 class OutputStream;
42 
43 class ElfWriter {
44  public:
45   // Looks up information about location of oat file in elf file container.
46   // Used for ImageWriter to perform memory layout.
47   static void GetOatElfInformation(File* file,
48                                    size_t* oat_loaded_size,
49                                    size_t* oat_data_offset);
50 
51   // Returns runtime oat_data runtime address for an opened ElfFile.
52   static uintptr_t GetOatDataAddress(ElfFile* elf_file);
53 
54   static bool Fixup(File* file, uintptr_t oat_data_begin);
55 
~ElfWriter()56   virtual ~ElfWriter() {}
57 
58   virtual void Start() = 0;
59   // Prepares memory layout of the whole ELF file, and creates dynamic symbols
60   // which point to specific areas of interest (usually section begin and end).
61   // This is needed as multi-image needs to know the memory layout of all ELF
62   // files, before starting to write them.
63   // This method must be called before calling GetLoadedSize().
64   virtual void PrepareDynamicSection(size_t rodata_size,
65                                      size_t text_size,
66                                      size_t bss_size,
67                                      size_t bss_methods_offset,
68                                      size_t bss_roots_offset,
69                                      size_t dex_section_size) = 0;
70   virtual void PrepareDebugInfo(const debug::DebugInfo& debug_info) = 0;
71   virtual OutputStream* StartRoData() = 0;
72   virtual void EndRoData(OutputStream* rodata) = 0;
73   virtual OutputStream* StartText() = 0;
74   virtual void EndText(OutputStream* text) = 0;
75   virtual void WriteDynamicSection() = 0;
76   virtual void WriteDebugInfo(const debug::DebugInfo& debug_info) = 0;
77   virtual bool End() = 0;
78 
79   // Get the ELF writer's stream. This stream can be used for writing data directly
80   // to a section after the section has been finished. When that's done, the user
81   // should Seek() back to the position where the stream was before this operation.
82   virtual OutputStream* GetStream() = 0;
83 
84   // Get the size that the loaded ELF file will occupy in memory.
85   virtual size_t GetLoadedSize() = 0;
86 
87  protected:
88   ElfWriter() = default;
89 };
90 
91 }  // namespace linker
92 }  // namespace art
93 
94 #endif  // ART_DEX2OAT_LINKER_ELF_WRITER_H_
95