Debug prefix macro search paths

[rmaz]

Macro search paths are generally absolute paths which will cause non-deterministic output for build systems that build remotely. When the -prefix-serialized-debugging-options flag is set remap the macro search paths as well as the other debug paths.

[cachemeifyoucan]

I think the macro path in swift module is only used for debugging purpose. Remapping with -debug-prefix-map sounds reasonable to me.

However in long term, we should rethink how all the remapping options are done because the interaction between multiple remapping options are going to be interesting.

[rmaz]

@swift-ci Please smoke test

[rmaz]

I think the macro path in swift module is only used for debugging purpose. Remapping with -debug-prefix-map sounds reasonable to me.

I was also considering disabling this serialization if this is an explicit module build, but couldn't confirm that we didn't need the macro search path logic in the debugger in that case. If we already have the modules built, would we need the macro lookup logic still?

[cachemeifyoucan]

I was also considering disabling this serialization if this is an explicit module build, but couldn't confirm that we didn't need the macro search path logic in the debugger in that case. If we already have the modules built, would we need the macro lookup logic still?

@adrian-prantl probably knows better. The plugin search paths are definitely used to create expression evaluator even for explicit module build, but explicit module build on latest swift should used resolved macro option only. That probably means you can use macro in lldb expression evaluator so we still want them to be there.

[rmaz]

@swift-ci Please smoke test

[rmaz]

@swift-ci Please smoke test

[cachemeifyoucan]

@swift-ci please test

[cachemeifyoucan]

Trigger full run, since this is debugging related.