Where do I find the assembly that creates a static variable in the .data section of my C program?

Question

First time poster. 2nd year CS student.

I am exploring the creation of static variables in the .data section of the Virtual Address Space in the context of a C sourc

Answer 1

My executable format is limited to old formats that aren't used anymore, but I'm pretty sure the code you're looking for does not exist in the ELF executable itself.

Executable files define sections that are copied/mapped to your process's memory verbatim. Just like your executable doesn't include code to populate the instruction stream of the functions it defines, it does not include code to populate static non-executable data. To that end, remember that there isn't any fundamental difference between data symbols and executable symbols: as far as storage is concerned, they're both data.

Some languages, like C++, will allow you to use dynamic initializers. Dynamic initializers are run before the entry point of your executable and populate data symbols with information that couldn't be inferred at compile-time. In that case, yes, there will be code for it. However, statically-initialized symbols don't need that, they can be copied or mapped straight to your process's address space.

Look at the data for staticVar closer. Forget the instructions for a bit; what happens if you put all the bytes next to one another?

01 00 00 00
02 00 00 00
03 00 00 00
04 00 00 00
05 00 00 00
06 00 00 00
07 00 00 00
08 00 00 00
09 00 00 00
ff ff ff ff

This is the hexadecimal representation of the sequence of little-endian integers {1, 2, 3, 4, 5, 6, 7, 8, 9, -1}, laid out in group of 4 bytes to make it easier to spot.