[llvm-dev] (Thin)LTO llvm build

[Carsten Mattner via llvm-dev]

On Fri, Sep 30, 2016 at 6:35 PM, Teresa Johnson <tejohnson at google.com> wrote:
> I just built a stage-1 compiler from the 3.9 release bits and built
> the lldb from head sources which worked fine. Let me try again using
> 3.9 build compiler to build 3.9 bits.

I had also started a build a few hours ago, what a coincidence. I had
to ditch both build and source trees because of cmake failing to
reconfigure due to some file it surprisingly had generated in the
source (not build) tree.

So, with -DBUILD_SHARED_LIBS=OFF, and a fresh checkout of the 3.9
release branch, I've run into the same error, this time only 39 (not a
typo, and not 3.9) ninja targets left.

Some parts finished, so here's a surprising size difference for clang-3.9.

LTO=OFF  stripped clang-3.9 is 44MB
LTO=Thin stripped clang-3.9 is 50MB

I would have expected more aggressive pruning or at least not an
increase, though I don't know if it can be caused by
-DBUILD_SHARED_LIBS=OFF.

FYI, -DLLVM_PARALLEL_LINK_JOBS=1 didn't seem to make any difference,
seeing how each LD stop was using all available cores.