Name Mangling

In compiler construction, name mangling (also called name decoration) is a technique used to solve various problems caused by the need to resolve unique names for programming entities in many modern programming languages.

It provides a way of encoding additional information in the name of a function, structure, class or another datatype in order to pass more semantic information from the compilers to linkers.

What is mangling? The C++ and Java languages provide function overloading, which means that you can write many functions with the same name, providing that each function takes parameters of different types. In order to be able to distinguish these similarly named functions C++ and Java encode them into a low-level assembler name which uniquely identifies each different version. This process is known as mangling.

参考：
Calling Conventions for different C++ compilers and operating systems: http://www.agner.org/optimize/calling_conventions.pdf
Name mangling demystified: http://www.int0x80.gr/papers/name_mangling.pdf
c++filt: https://sourceware.org/binutils/docs/binutils/c_002b_002bfilt.html#c_002b_002bfilt

The C++ language does not define a standard decoration scheme, so each compiler uses its own. Few linkers can link object code that was produced by different compilers.

不同 C++ 编译器使用的 Mangling 规则可能不一样，这里 How different compilers mangle the same functions 有不同编译器采用不同 Mangling 规则的例子。

$ cat 1.c
int fun1(char*, int, double, char, float)
{
    return 1;
}
$ g++ -c 1.c    # Use g++, rather than gcc.
$ nm 1.o | grep fun1
0000000000000000 T _Z4fun1Pcidcf