r218063 - Patch to check at compile time for overflow when

[jahanian]

On Sep 18, 2014, at 1:03 PM, Nico Weber <thakis at chromium.org> wrote:

> On Thu, Sep 18, 2014 at 11:38 AM, jahanian <fjahanian at apple.com> wrote:
> 
> On Sep 18, 2014, at 11:33 AM, Reid Kleckner <rnk at google.com> wrote:
> 
> > Cool! Do these warnings fire on plain memcpy if the system headers don't arrange for memcpy to route to __builtin__memcpy_chk? If so, can you add tests for plain prototyped memcpy as you did for strlcpy in the previous test?
> >
> 
> No they don’t. Note that __builtin__memcpy_chk, etc. will have an added argument,  __builtin_object_size,  which will have
> the size of destination buffer and is needed to do the checking.
> 
> But you can just call the code that does the computation that __builtin_object_size does when checking memcpy, right?

I am not sure what you mean. memcpy does not do any checking for overflow. You may do the checking for overflow before calling
memcpy yourself (essentially do what __builtin_memcpy_chk does).

- Fariborz



>  
> 
> - Fariborz
> 
> 
> 
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