Memories of an old bug

Long ago, when I was working on my toy compiler, I hit a strange bug that caused compiled programs to crash when they called into libc functions via the runtime. I traced it back to an ABI requirement that I was not aware of: stack frames on Linux must be aligned to 16 bytes, apparently for the sake of SSE instructions.

Years later I was tickled to discover I was not the only one to write the same bug.

See also

• "Notes on (memory) alignment" (Sep 2025)
• "A subtle garbage collector bug" (Jul 2020)