Warnings have been added for three cases (PR41905): (1) missing debug info, (2)
the source file cannot be found, (3) the debug info points at a line beyond the
end of the file.
(1) as it stands is confusing (when there is no debug info it should not error for failed to parse).
This was brought up once on http://lists.llvm.org/pipermail/llvm-dev/2020-April/141264.html and an internal
user mentioned it to me that it was annoying. (I personally ignore the warning.)
This patch changes the warning to only fire when LLVMSymbolizer::symbolizeCode returns an Error
(There is currently no test for an Error return value.
The only code path is probably a broken symbol table, but we probably already emit a warning
in that case)
If we still need a warning for a binary with no debug info, we should do it properly.