On Monday, 17 November 2014 at 23:14:32 UTC, Vladimir Panteleev
wrote:
I proposed to build Phobos and Druntime with stack frames
enabled:
https://issues.dlang.org/show_bug.cgi?id=13726
Stack frames add three CPU instructions to each function (two
in the prolog, and one in the epilog). This creates a linked
list which debuggers, profilers, etc. can easily walk to find
which function called which. They would allow debugging certain
classes of bugs much more easily (e.g. the recurring
InvalidMemoryOperationError - there's a thread about it in
D.learn just today), and profiling your code with polling
(non-instrumenting) profilers.
Having run into that error myself on Android/x86
(https://github.com/D-Programming-Language/druntime/pull/784#issuecomment-42768642),
it would be nice if it was easier to trace. Losing 0.1%
performance certainly seems worth it, but you'd think anyone
tracking such an issue could recompile druntime/phobos
themselves. I was unaware that the "-gs" flag would help though,
and nobody seems to have mentioned it in the forums or github
until you just did.
I guess the main issue is whether we're sure it doesn't get much
worse than 0.1%, ie that there aren't degenerate cases where we
get worse performance declines. Also, there's the principle of
whether we want to force a small performance penalty, however
minute, onto release builds of druntime/phobos for better
debugging, which is what Walter and Martin seem to be against.
