GNAT can generate code to zero-out hardware registers before returning from a subprogram.
It can be enabled with the -fzero-call-used-regs=`choice'
command-line option, to affect all subprograms in a compilation, and
with a Machine_Attribute pragma, to affect only specific
subprograms.
procedure Foo; pragma Machine_Attribute (Foo, "zero_call_used_regs", "used"); -- Before returning, Foo scrubs only call-clobbered registers -- that it uses itself. function Bar return Integer; pragma Machine_Attribute (Bar, "zero_call_used_regs", "all"); -- Before returning, Bar scrubs all call-clobbered registers.
For usage and more details on the command-line option, on the
zero_call_used_regs attribute, and on their use with other
programming languages, see Using the GNU Compiler Collection (GCC).