Normalizing Dependencies

Procedure

For a third-party library, compile its source code to generate library files. Create paths of different architectures (for example, xx/lib/aarch64 and xx/lib/x86_64) and then place the compiled library files in corresponding paths. In the compilation script, modify the paths for compilation and linking so that the library file in the corresponding architecture is automatically selected.

Example:

In the following code example, a libcrc32.so dynamic library is compiled for dependency normalization so that the library can run on both the Kunpeng and x86 platforms.

• Compile and generate Kunpeng and x86 dynamic libraries.

  Compile the following basic code on the Kunpeng and x86 platforms to generate libcrc32.so files, and save them to the xx/lib/x86_64 and xx/lib/aarch64 directories respectively.

  crc32.cpp

  #include "crc32.h" 
  #ifdef __x86_64__
  uint32_t crc32_u8(uint32_t crc, uint8_t value) 
  {
      __asm__("crc32b %1, %0" : "+r"(crc) : "rm"(value));
      return crc;
  }
  #endif
  #ifdef __aarch64__
  uint32_t crc32_u8(uint32_t crc, uint8_t value) 
  {
      __asm__("crc32cb %w[c], %w[c], %w[v]":[c]"+r"(crc):[v]"r"(value));
      return crc;
  }
  #endif

  crc32.h

  #ifndef CRC32__HHHH_HH
  #define CRC32__HHHH_HH
  #include <stdint.h>
  uint32_t crc32_u8(uint32_t crc, uint8_t v);
  #endif

  Compile the dynamic library:

  g++ crc32.cpp -I ./include -fPIC -shared -o libcrc32.so 

  

  For the Kunpeng platform, add the -march=armv8-a+crc compilation option. ./include indicates the actual path of the crc32.h file.

• Modify the compilation script.

  Modify the compilation script so that the target path is automatically selected based on the architecture during compilation and linking.

  #!/bin/bash
  ARCH_TYPE=`uname -m`
  if [ "$ARCH_TYPE" = "x86_64" ];then
  g++ main.cpp -I ./include/ -L ./lib/x86_64/ -lcrc32 -o main
  fi
  if [ "$ARCH_TYPE" = "aarch64" ];then
  g++ main.cpp -I ./include/ -L ./lib/aarch64/ -lcrc32 -o main
  fi

  The structure of the sample project file is as follows:

  crc32Project
  ├── build.sh
  ├── include
  │   └── crc32.h
  ├── lib
  │   ├── aarch64
  │   │   └── libcrc32.so
  │   └──x86_64
  │       └── libcrc32.so
  └── main.cpp