[llvm] [llvm-dwp] turn duplicate dwo id into warning, continue to gen dwp (PR #121193)

[Jinjie Huang via llvm-commits]

Labman-001 wrote:

> Is there a case for it to be a warning, other then binutils does it?

One case is when multiple .a files in a project contain duplicate .o files. The linker can link them normally, but llvm-dwp reports an error during the process, which is somewhat counterintuitive. In such a scenario, it might be better to generate a DWP like binutils dwp does?

> One way of looking at it, this will produce incomplete, broken(?), debug information,

Those duplicate DWOs  seem to be redundant when generating DWP?
Regarding skipping duplicate DWO IDs, I tested the generated DWP with GDB (13.2) and LLDB (7.0), and they can consume the DWP normally.

And btw, it seems we don't need to add an option to control the behavior when encountering duplicate DWOs?

https://github.com/llvm/llvm-project/pull/121193