Re: [PATCH 0/4] Makefile: micro-optimize light non-test builds

On Tue, Jan 26, 2021 at 05:07:04PM +0100, Ævar Arnfjörð Bjarmason wrote:

This small series speeds up builds where you just want to get to a
working "git" binary, but don't care about running git's own tests, or
about making/installing fallbacks for "git svn" et al (which we do
even with NO_PERL).

I have to wonder if you really care about non-builtins here. If not,
then doesn't "make git" do what you want?

I recently did something similar, but a bit more extreme. I have a
100-patch series introducing annotations/fixes for -Wunused-parameter. I
rebased it on master, and the end result had a compile error (a
previously unused and annotated parameter became used). So I wanted not
just to fix it, but to put the fix in the right commit.

Doing:

  git rebase -x 'make -j16'

builds each commit and stops when we hit the breakage, which is nice.
But it takes a while to build, and a non-trivial bit of time is spent
generating libgit.a, running the linker, making builtin hardlinks, etc.

I ended up putting:

  objects: $(LIB_OBJS) $(BUILTIN_OBJS) git.o

into my config.mak, and then "make objects" is quite fast. Probably too
gross a hack to carry in our Makefile, but I was tempted to send it.

-Peff