On May 5, 2014, at 3:21 PM, David Chisnall <thera...@freebsd.org> wrote:
> On 5 May 2014, at 20:49, Pedro Giffuni <p...@freebsd.org> wrote:
>
>> Yes, but I reverted it because there are other ways to check for overflows
>> without the performance hit.
>
> Do we have a good reusable routine for doing this somewhere? Clang and gcc
> both have some idiom recognisers that try to spot when people are attempting
> to do this. Clang also has a builtin, which would be good to use when
> available. Overflow checking is very cheap on modern CPUs (add, branch on
> carry), so it would be nice if we could start looking for this malloc() and
> realloc() pattern and replacing the multiply with something that checks for
> the error.
reallocf():
The reallocf() function is identical to the realloc() function, except
that it will free the passed pointer when the requested memory cannot be
allocated. This is a FreeBSD specific API designed to ease the problems
with traditional coding styles for realloc() causing memory leaks in
libraries.
...
The reallocf() function first appeared in FreeBSD 3.0.
Warner
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