Tiny C Compiler, also known as TCC, is a small C compiler (hence, the name) that also outputs teeny, tiny binaries.

To install on linux, use: sudo apt install tcc

TCC uses a lot of size optimization flags by default. However, we can shrink the binary even more.

tcc -Os -m32 -ffunction-sections -fdata-sections

-Os tells TCC to optimize for file size, rather then performance.

-m32 tells TCC to compile for 32-bit, which frees up more space.

To see how much space we are saving, we will compare TCC to GCC.

Sample code:

#include <stdlib.h>
int main() {
  printf("HI!\n");
  return 0;
}

Flags: -m32 -Wall -Os -ffunction-sections -fdata-sections

Results: GCC: 15540 bytes TCC: 2404 bytes

TCC binaries are small enough to fit into QR codes.