On Thursday, 31 July 2014 at 20:49:18 UTC, Timon Gehr wrote:
On 07/31/2014 09:37 PM, Jonathan M Davis wrote:
disable contracts, turn assert(0) into a halt
instruction, and disable bounds checking in @system and
@trusted code.
So, if you want to keep the assertions and contracts and
whatnot in,
Unfortunately, if used pervasively, assertions and contracts
and whatnot may actually hog the speed of a program in a way
that breaks the deal.
Disabling assertions (and whatnot), assuming assertions to be
true (and disabling whatnot) and leaving all assertions and
whatnot in are different trade-offs, of which assuming all
assertions to be true is the most dangerous one. Why hide this
behaviour in '-release'?
I'm afraid that I don't see the problem. If you want assertions
left in in your release/production builds, then don't use
-release. If you want them removed, then use -release. Are you
objecting to the fact that the compiler can do further
optimizations based on the fact that the assertions are presumed
to be true if they're removed? I really don't see any problem
with that. You're screwed regardless if the assertions would have
failed. By their very nature, if an assertion would have failed,
your program is an invalid state, so if you don't want to risk
having code run that would have failed an assertion, then just
don't compile with -release. And if you are willing to assume
that the assertions won't fail and have them disabled in your
release build, then you might as well gain any extra
optimizations that can be made from assuming that the assertion
is true. You're already making that assumption anyway and
potentially letting your program enter an invalid state.
just don't use -release and use -boundscheck=safe to get the
bounds
checking changes that -release does.
- Jonathan M Davis
This leaves assertions and contracts in though.
Which is precisely what Ary was looking to do. He wanted to use
-release but not have assertions removed, and using
-boundscheck=safe instead of -release does that (though further
posts by him seem to indicate that he doesn't want the @system
bounds checking removed either, which means that he should just
skip -release and all related flags entirely).
- Jonathan M Davis
