On Tue, Aug 24, 2021 at 01:08:58PM -0700, Nathan Chancellor wrote:
The LLVM developers are under the impression that this is an issue with
objtool; specifically quoting Eli Friedman:
"The backend can, in general, create basic blocks that don't contain any
instructions, and don't fall through to another block. A jump table entry
can refer to such a block. I guess certain tools could be confused by this.
If that's the issue, it should be possible to work around it using '-mllvm
So jump-tables are a weak point; ARM64 was having worse problems than
x86 there, they can't even locate them.
As to having a jump-table entry to an empty block and not falling
through; how are we supposed to know?
Emitting them is a waste of space, so I'd say it's a compiler bug :-))
It's been brought up before; but perhaps we should look at an 'informal'Not a bad idea, especially if this has come up before.
ABI for jump-tables ?