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

From: Jeff King <peff@peff.net>
Date: Jan 26, 2021, 21:16 UTC
Message-ID: <YBCGtd9if0qtuQxx@coredump.intra.peff.net>
In-Reply-To: <20210126160708.20903-1-avarab@gmail.com>

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