On 4/8/24 5:04 PM, Iain Sandoe wrote:
Hi
PR 109627 is about functions that have had their bodies completely elided, but
still have the wrappers for EH frames (either .cfi_xxx or LFSxx/LFExx).
These are causing issues for some linkers because such functions result in FDEs
with a 0 code extent.
The simplest representation of this is (from PR109527)
void foo () { __builtin_unreachable (); }
With the possibility of sounding like a broken record, I think
__builtin_unreachable is fundamentally flawed. It generates no code
and just lets the program continue if ever "reached". This is a
security risk and (IMHO) just plain silly. We're in a situation that is
never supposed to happen, so continuing to execute code is just asking
for problems.
If it were up to me, I'd have __builtin_unreachable emit a trap or
similar construct that should (in general) halt execution.
Jeff
