-wmo specifically is deliberately not visible because we didn't want people using it casually. It's too jargony, and not something we want people to add to their builds without at least knowing what it stands for. It's mostly for us compiler people to test things by modifying existing command lines.

Comment by Dmitry Shevchenko (JIRA)

Are there flags that have "public" short form variants? If not I think we can close this.

There are a few. -c is actually an alias for -emit-object because Past Jordan wanted consistency for outputs. You can see that in the help output, ad hoc:

  -emit-assembly         Emit assembly file(s) (-S)
  -emit-bc               Emit LLVM BC file(s)
  -emit-executable       Emit a linked executable
  -emit-imported-modules Emit a list of the imported modules
  -emit-ir               Emit LLVM IR file(s)
  -emit-library          Emit a linked library
  -emit-object           Emit object file(s) (-c)
  -emit-sibgen           Emit serialized AST + raw SIL file(s)
  -emit-sib              Emit serialized AST + canonical SIL file(s)
  -emit-silgen           Emit raw SIL file(s)
  -emit-sil              Emit canonical SIL file(s)

Looking at Options.td, I see

-### -driver-print-jobs
-h -help
-warn-swift3-objc-inference -warn-swift3-objc-inference-complete (mostly for compatibility while changing the name)
-c -emit-object
-S -emit-assembly

and a bunch of forms that allow equal signs instead of separate args. So maybe it's not worth it to do anything general.

Comment by Dmitry Shevchenko (JIRA)

Yep, having them in the description of the long options is good enough IMO