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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_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 
     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