Faster linking (-gsplit-dwarf, gold/lld, --gdb-index)

[Luboš Luňák]

On Wednesday 10 of October 2018, Stephan Bergmann wrote:
> The underlying issue is that the internals of Clang's UBSan use the
> Itanium ABI's notion of type equality (checking for RTTI pointer
> equivalence), not GCC's weaker notion (checking for RTTI string
> equivalence).  That requires some adjustments when building LO for
> UBSan, to make sure RTTI for types used across library boundaries gets
> exported from libraries.  I don't think we are doing anything inherently
> "right" or "wrong" here.

 I get that, but what I'm saying is that if we do need to pass obscure 
seemingly unrelated options to the compiler to make UBSan work, then we are 
either working around problems that UBSan should be responsible for, or we 
are doing something wrong. And maybe what we do is realistically the best 
choice, but we should at least stop for a moment before adding a workaround 
for a workaround for a workaround.

> If you plan to make choice of --enable-ld=... implicit in configure.ac,
> then yes, please do so in a way that verifies that the implicitly chosen
> linker supports --dynamic-list-cpp-typeinfo if that will be needed by
> the build's solenv/gbuild/platform/unxgcc.mk.

 It's a corner case, but fair enough.

-- 
 Luboš Luňák
 l.lunak at collabora.com