For
void f();
int main() { f(); }
`lld -demangle` now produces
ld64.lld: error: undefined symbol: f
>>> referenced by path/to/main.o:(symbol main+0x8)
instead of
ld64.lld: error: undefined symbol: _f
>>> referenced by path/to/main.o:(symbol _main+0x8)
previously. (Without `-demangle`, it still prints `_f` and `_main`.)
This does *not* match ld64's behavior, but it does match e.g. lld/COFF's
behaviour.
This is arguably easier to understand: clang prepends symbol names with `_`
on macOS, so it seems friendly if the linker removes it again in its
diagnostics. It also makes the `extern "C"` insertion diagnostics we added
recently look more self-consistent.
Differential Revision: https://reviews.llvm.org/D135189
062c660dbf