increase binary executable size

Question

Abstract problem: I have some code in C. After compilation the executable has 604 KB. I'd like it to be bigger, let's say 100 MB.

How to achieve this?

I could declare a string to increase binary size, but is there any more scalable solution. That is I'd like to increase compiled size by N bytes without increasing source code by N bytes.

 char* filler = "filler"; // increases compiled size only by few bytes

Use case: I'm developing firmware, and testing remote firmware upgrade feature. I'd like to see how it will behave when firmware is big and heavy.

Answer 1

This creates a 100MB executable when compiled with gcc:

#include <stdio.h>
#define SIZE 100000000

char dummy[SIZE] = {'a'};

int main(void){
    dummy[SIZE-1] = '\n';
    if(dummy[0] == 'a')printf("Hello, bloated world");
    return 0;
}

By defining the array outside of main you don't blow the stack. By using the array, gcc doesn't optimize it away.

Answer 2

GCC specific variant:

char dummy[100*1024*1024] __attribute__((used)) = { 77 };

Applying the attribute 'used', you do not need to touch it any more to prevent it from being optimised away. Still, an non-all-null initialiser must be applied as in John Coleman's solution.