isra is the suffix added to the function name when gcc option -fipa-sra compiler optimization being carried out.

从gcc manual开始：

-fipa-sra

Perform interprocedural scalar replacement of aggregates,removal of unused
parameters and replacement of parameters passed by reference by parameters passed
by value.

Enabled at levels -O2,-O3 and -Os.

在此选项下优化的所有函数都会在其名称后附加isra.我深入研究了gcc代码并找到了附加字符串的函数.

tree
clone_function_name (tree decl,const char *suffix)
{
  tree name = DECL_ASSEMBLER_NAME (decl);
  size_t len = IDENTIFIER_LENGTH (name);
  char *tmp_name,*prefix;

  prefix = XALLOCAVEC (char,len + strlen (suffix) + 2);
  memcpy (prefix,IDENTIFIER_POINTER (name),len);
  strcpy (prefix + len + 1,suffix);
#ifndef NO_DOT_IN_LABEL
  prefix[len] = '.';
#elif !defined NO_DOLLAR_IN_LABEL
  prefix[len] = '$';
#else
  prefix[len] = '_';
#endif
  ASM_FORMAT_PRIVATE_NAME (tmp_name,prefix,clone_fn_id_num++);
  return get_identifier (tmp_name);
}

这里,参数2,const char *后缀是“isra”,并注意函数宏ASM_FORMAT_PRIVATE_NAME的底部,它将clone_fn_id_num作为其第三个参数.这是在“isra”之后找到的任意数字.其名称是在此编译器选项下克隆的函数计数(或者可以是跟踪所有克隆函数的全局计数器).

如果你想了解更多,请在文件gcc / tree-sra.c中搜索modify_function,然后调用cgraph_function_versioning(),它将“isra”作为最后一个参数.