Re: uninorm/composition.c:75:22: runtime error

[Paul Eggert]

On 3/13/22 00:04, Simon Josefsson wrote:
> Reading the ideas in your responses, I think gnulib could help
> developers to use ASan/UBSan in their project by assisting with these
> choices.  I'll see if I can come up with anything that is generally
> useful, once I get a couple of projects to build and self-test reliably
> with ASan/UBSan.

Something like --enable-gcc-warnings, but --enable-sanitizer? That would 
be helpful.

For what it's worth, I just now built GNU Emacs with 'clang 
-fsanitize=undefined' and it complained several times about adding 0 to 
a null pointer, due to code that's in Emacs not in Gnulib. I worked 
around the problem by compiling with '-fsanitize=undefined 
-fno-sanitize=pointer-overflow'. Of course this disables some useful checks.

It is a pain that Clang is wrongheadedly pedantic here. Adding 0 to a 
null pointer is well-defined in C++17, and there's no realistic 
possibility of Clang being ported to a platform where it's undefined 
behavior in C.