How can I create an executable .exe PE file manually?

Question

All texts on how to create a compiler stop after explaining lexers and parsers. They don\'t explain how to create the machine code. I want to understand the end-to-end process.<

Answer 1

Executable file format is dependent on the OS. For windows it is PE32(32 bit) or PE32+(64 bit).

The way the final executable look like depends on the ABI (application binary interface) of the OS. The ABI tells how the OS loader should load the exe and how it should relocate it, whether it is dll or plain executable etc..

Every object file(executable or dll or driver) contains a part called sections. This is where all of our code, data, jump tables etc.. are situated.

Now, to create an object file, which is what a compiler does, you should not just create the executable machine code, but also the headers, symbol table, relocation records, import/export tables etc..

The pure machine code generation part is completely dependent on how much optimized you want your code to be. But to actually run the code in the PC, you must have to create a file with all of the headers and related data(check MSDN for precise PE32+ format) and then put all of the executable machine code(which your compiler generated) into one of the sections(usually code resides in section called .text). If you have created the file conforming to the PE32+ format, then you have now successfully created an executable in windows.