Driver options taking a value typically use `=` as the separator, instead of a
space. Unfortunately many older driver options do not stick with the rule, but I
find -Xclang used a lot and will be convenient if -Xclang= exists.
For build systems using a string array instead of a string to indicate compiler options,
`["-Xclang=-foo"]` is more convenient than `["-Xclang", "-foo"]`.
If a tool wants to filter out -Xclang=-foo, it is trivial for the `=` form, but
complex for the space separated form.
Reviewed By: jhuber6
Differential Revision: https://reviews.llvm.org/D131455
- Don't break using '-mllvm -disable-llvm-optzns' (yet).
- Don't add support for '-mllvm -disable-llvm-passes'.
This is important for LLVM 4 as we haven't yet really told folks this is
coming. I'll add release notes about this.
I've also added some explicit testing of this so its more obvious what
is happening here.
llvm-svn: 291850
Fangrui Song