Re: [PATCH 1/2] git version --build-options: report the build platform, too

[Eric Sunshine <sunshine@sunshineco.com>]

On Fri, Dec 08, 2017 at 04:19:25PM -0500, Eric Sunshine wrote:
> On Fri, Dec 8, 2017 at 4:17 PM, Eric Sunshine <sunshine@sunshineco.com> wrote:
> > On Fri, Dec 8, 2017 at 12:43 PM, Junio C Hamano <gitster@pobox.com> wrote:
> >> Jonathan Nieder <jrnieder@gmail.com> writes:
> >>> Can this use GIT_BUILD_PLATFORM directly instead of going via the indirection
> >>> of a mutable static string?  That is, something like
> >>>
> >>>               printf("machine: %s\n", GIT_BUILD_PLATFORM);
> >>
> >> Good point.  And if this is externally identified as "machine",
> >> probably the macro should also use the same word, not "platform".
> >> We can go either way, as long as we are consistent, though.
> >
> > In Autoconf parlance, this would be called "host architecture" (GIT_HOST_ARCH).
> 
> My bad: "host cpu", rather (GIT_HOST_CPU).

Dscho, when you re-roll, perhaps replace the current patch with the
one below which determines the CPU type automatically rather than
having to manually maintain and augment a bunch of #ifdefs in help.h.

I took the liberty of renaming the #define to GIT_HOST_CPU to better
match Autoconf parlance since its conceivable that Git might some day
support cross-compilation officially via the configure script (which
doesn't yet work, though I have some patches which begin addressing
that, but that's a separate topic).

The original plan was to keep Adric Norris as author, but by the time
the patch was done and the commit message rewritten to match, I
realized that none of his work remained, thus ended up dropping his
authorship and both of your sign-offs. Sorry.

--- >8 ---
From: Eric Sunshine <sunshine@sunshineco.com>
Date: Sat, 9 Dec 2017 04:09:18 -0500
Subject: [PATCH] help: version --build-options: also report host CPU

It can be helpful for bug reports to include information about the
environment in which the bug occurs. "git version --build-options" can
help to supplement this information. In addition to the size of 'long'
already reported by --build-options, also report the host's CPU type.
Example output:

   $ git version --build-options
   git version 2.9.3.windows.2.826.g06c0f2f
   cpu: x86_64
   sizeof-long: 4

New Makefile variable HOST_CPU supports cross-compiling.

Suggested-by: Adric Norris <landstander668@gmail.com>
Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
---
 Makefile | 9 +++++++++
 help.c   | 1 +
 2 files changed, 10 insertions(+)

diff --git a/Makefile b/Makefile
index fef9c8d272..5587bccc93 100644
--- a/Makefile
+++ b/Makefile
@@ -425,6 +425,9 @@ all::
 #
 # to say "export LESS=FRX (and LV=-c) if the environment variable
 # LESS (and LV) is not set, respectively".
+#
+# When cross-compiling, define HOST_CPU as the canonical name of the CPU on
+# which the built Git will run (for instance "x86_64").
 
 GIT-VERSION-FILE: FORCE
 	@$(SHELL_PATH) ./GIT-VERSION-GEN
@@ -1095,6 +1098,12 @@ else
 BROKEN_PATH_FIX = '/^\# @@BROKEN_PATH_FIX@@$$/d'
 endif
 
+ifeq (,$(HOST_CPU))
+	BASIC_CFLAGS += -DGIT_HOST_CPU="\"$(firstword $(subst -, ,$(uname_M)))\""
+else
+	BASIC_CFLAGS += -DGIT_HOST_CPU="\"$(HOST_CPU)\""
+endif
+
 ifneq (,$(INLINE))
 	BASIC_CFLAGS += -Dinline=$(INLINE)
 endif
diff --git a/help.c b/help.c
index 88a3aeaeb9..cbcb159f36 100644
--- a/help.c
+++ b/help.c
@@ -412,6 +412,7 @@ int cmd_version(int argc, const char **argv, const char *prefix)
 	printf("git version %s\n", git_version_string);
 
 	if (build_options) {
+		printf("cpu: %s\n", GIT_HOST_CPU);
 		printf("sizeof-long: %d\n", (int)sizeof(long));
 		/* NEEDSWORK: also save and output GIT-BUILD_OPTIONS? */
 	}
-- 
2.15.1.502.gccaef8de57