[RFC] Sanitizers difference in between GCC and LLVM

[Martin Liška]

Hi.

I would like to use this thread to slightly describe differences in GCC and LLVM.
I compared options support by both and:

UBSAN:

1)
gcc: error: unrecognized argument to -fsanitize= option: ‘nullability-arg’
gcc: error: unrecognized argument to -fsanitize= option: ‘nullability-assign’
gcc: error: unrecognized argument to -fsanitize= option: ‘nullability-return’

I guess it's covered by -fsanitize=nonnull-attribute and -fsanitize=returns-nonnull-attribute.
One can't have in GCC a local variable with non-null attribute (nullability-assign), right?

2) unsigned-integer-overflow

As documented, not being a real UBSAN. Do we want that or seen as not useful?

3) function

Indirect function pointer comparison using RTTI in C++. Would it be useful? Ideas?

ASAN:

For ASAN, there's quite up-to-date page: https://github.com/google/sanitizers/wiki/AddressSanitizerClangVsGCC-(5.0-vs-7.1)

The page is quite up-to-date. Currently we should cover all what LLVM supports. Am I right? Or is there any interesting
feature we miss?

Thanks for ideas,
Martin