[LLVMdev] [RFC] Removing static initializers for command line options

[Rafael Espíndola]

> I strongly feel this is the wrong decision. If you have a single process using two LLVM clients (say WebKit and Mesa), and they both are using an opt pass with different settings. If the storage is global this will not work.

That is only an issue if they can set the option at all.

To summarize, the point is that there are two *very* different types of options

* Nobs for which there is not a single right answer for all users.
There are very few of these currently and we expect it to remain like
that. These should not use cl::opt or static storage at all. They
should be an option passed to the constructor of the pass.  It may
also involve exposing it to the C api and the PassManagerBuilder.

* Options that we use during development of llvm. They are useful for
testing, tracking a bug or enabling/disabling a feature that is still
under development. These can use a static storage since external
clients like webkit will never change them. We do have to avoid these
options requiring static constructors, since otherwise the client is
paying for something it will never use.

Cheers,
Rafael