[PATCH] D26649: [CMake] Support lld with LTO bootstrap

[Mehdi AMINI via cfe-commits]

mehdi_amini added a comment.

In https://reviews.llvm.org/D26649#595361, @phosek wrote:

> In https://reviews.llvm.org/D26649#595356, @mehdi_amini wrote:
>
> > In https://reviews.llvm.org/D26649#595296, @phosek wrote:
> >
> > > It's sufficient, I just tested it.
> >
> >
> > How did you check it? I don't understand how LLVM_ENABLE_LLD is propagated to stage-2?
>
>
> Sufficient as in Clang looks for lld in the same directory where `clang`/`clang++` binary is first so we don't need to explicitly pass the path to lld to later stages.


OK, but still, LLVM_ENABLE_LLD needs to be passed to stage-2, so it needs to be actually BOOTSTRAP_LLVM_ENABLE_LLD. 
I looked at all the CMake `_PASSTHROUGH` and didn't find it mentioned anywhere. We could make it auto-forwarded in this case maybe, @beanz is best to answer this.

Have you looked into turning `if(LLVM_ENABLE_LLD)` into `if(BOOTSTRAP_LLVM_ENABLE_LLD)`?
Technically we may want to have the stage-2 linked with lld even if lld is not on the system and not available during stage1.


Repository:
  rL LLVM

https://reviews.llvm.org/D26649