• =?UTF-8?B?Tm9yZGzDtnc=?= (5/5) May 13 2016 What role does the DMD flags -gs and -gx play?
• Rene Zwanenburg (12/14) May 13 2016 IIRC, not emitting a stack frame is an optimization which

=?UTF-8?B?Tm9yZGzDtnc=?= <per.nordlow gmail.com> writes:

What role does the DMD flags -gs and -gx play?

The documentation says

   -gs            always emit stack frame
   -gx            add stack stomp code

which I don't know what it means.

Rene Zwanenburg <renezwanenburg gmail.com> writes:

On Friday, 13 May 2016 at 10:19:04 UTC, Nordlöw wrote:
   -gs            always emit stack frame

IIRC, not emitting a stack frame is an optimization which 
confuses debuggers. So I think this can be used to make optimized 
builds a bit easier to debug.

   -gx            add stack stomp code

After a function returns the stack normally still contains the 
local variables of that function, but they can be overwritten at 
any time (which is why it's unsafe to escape references to stack 
variables from a function). Using this switch will cause the 
compiler to overwrite the stack with bogus values before 
returning, which will help with early detection of bugs like the 
above. It can also be useful in security contexts where a 
function operates on sensitive data.