-fstack-protector and STL string

[Florian Weimer]

On 03/24/2016 12:32 PM, Martin Richtarsky wrote:

> we are using the -fstack-protector compiler option with gcc 5.x to detect
> stack smashing. While analyzing a performance regression resulting from
> this I found the instrumentation is also done for our STL string
> implementation which has an interned buffer for short strings. So
> basically a function having an object of that string class on the stack
> would incur some performance overhead due to checking, although it can be
> argued that the string class is pretty safe.

I don't think this is true.  If your implementation matches typical 
std::string classes (I assume it does because of “STL string”), it has 
iterators which allow easy out-of-bounds write access.

Florian