On Tue, Mar 22, 2022 at 12:44 AM Masahiro Yamada <masahiroy@xxxxxxxxxx> wrote: > > On Wed, Mar 16, 2022 at 11:51 AM Chun-Tse Shao <ctshao@xxxxxxxxxx> wrote: > > > > Tue, Mar 08, 2022 at 01:01:45PM +0900, Masahiro Yamada wrote: > > > On Tue, Mar 8, 2022 at 7:50 AM Chun-Tse Shao <ctshao@xxxxxxxxxx> wrote: > > > > > > > > On Mon, Mar 07, 2022 at 10:17:17AM -0800, Nick Desaulniers wrote: > > > > > On Sun, Mar 6, 2022 at 2:39 PM Chun-Tse Shao <ctshao@xxxxxxxxxx> wrote: > > > > > > > > > > > > Add HOSTPKG_CONFIG to allow tooling that builds the kernel to override > > > > > > what pkg-config and parameters are used. > > > > > > > > > > Sorry, kind a late thought here for v4, but we don't seem to prefix > > > > > many other host side tools with HOST_, i.e. LEX, YACC, AWK, PERL, > > > > > PYTHON3, etc. Maybe just having the variable identifier be simply > > > > > PKGCONFIG rather than HOSTPKG_CONFIG then put it at the end of the > > > > > list in the top level Makefile after ZSTD (i.e. the list of host > > > > > tools)? There's HOST_ prefixes when there's more than one tool > > > > > involved (i.e. host compiler vs target compiler), but I suspect > > > > > there's no such distinction for the existing uses of pkg-config? > > > > > > > > > Thanks for your suggestion, Nick! Yes I think it makes sense with PKGCONFIG > > > > instead of HOSTPKG_CONFIG since there is only one tool involved. I will > > > > work on it and submit a new patch. > > > > > > > > > > Please hold on. > > > > > > I was also wondering what to do with the "HOST" prefix. > > > > > > Libraries are usually arch-dependent. > > > (in other words, pkg-config should return different library paths > > > for $(CC) and $(HOSTCC) ) > > > > > > You already understood this, so you added "HOST" prefix. > > > > > > > > > Please let me take time for further discussion. > > > I will come back to this when I get some time. > > > > > > > > > > Hi Mashiro, > > > > I was wondering if you were able to look more into this. > > > > Thank you! > > > > -CT > > > > > In the meantime, > > > a8a5cd8b472ca20e5b8fa649c43b3756867322f8 > > > as reference info if you have not seen it. > > > > > > > > > How many distros support something like > > > "aarch64-linux-gnu-pkg-config" ? > > > > > > Ubuntu 18.04 and 20.04 seem to support it. > > > I do not know for others. > > > > > > > > > > > > > > > > Sorry for the delay. > I am OK with the idea of allowing users to override the pkg-config command, > but I tend to take time before making a decision. > > > > > Does anybody have any insight / thoughts about the following points? > > > > > > > [Q1] with/without "HOST" prefix > > > Apparently, "pkg-config" should return different libs/cflags > for $(CC) and $(HOSTCC). > > I think the non-prefixed macro name "PKG_CONFIG" should be > reserved for $(CC) (building for the target system). Ok. I retract my comment on v4 about removing the HOST prefix then. > > "HOSTPKG_CONFIG" looks unbalanced > due to the underscore. > > Perhaps, "HOST_PKG_CONFIG" might be better? I'm fine with HOSTPKG_CONFIG (what's in v4); follows the style of HOSTCC and HOSTCXX. > > > > > [Q2] "pkg-config" vs "pkgconf" > > The traditional pkg-config implementation [1] is not actively > maintained these days. > The last commit was more than one year ago. > > The alternative one 'pkgconf' [2] is more active. > > In fact, Fedora already switched to 'pkgconf' [3]. > Now 'pkg-config' is just a wrapper of 'pkgconf'. > Many distributions already support pkgconf. > > > I considered the shorter macro name "HOSTPKGCONF" and > > HOSTPKGCONF = pkgconf > > but I am not sure if this is the right decision. > Maybe we should stick to "PKG_CONFIG" / "HOST_PKG_CONFIG" > for the macro names. > > > [1] https://gitlab.freedesktop.org/pkg-config/pkg-config.git > [2] https://github.com/pkgconf/pkgconf.git > [3] https://fedoraproject.org/wiki/Changes/pkgconf_as_system_pkg-config_implementation If the folks sending this are working on CrOS, better find what's in their build system. Chun-Tse? (I feel like I'm behind the times again, like when `apt-get install` became old news in favor of `apt install`...) > > > > > > [Q3] What is the trend of handling cross-compile by pkg-config (or pkgconf). > > > By default, pkg-config returns the libs/cflags for native builds. > > For cross builds, the search paths for the *.pc files must be changed > via the "PKG_CONFIG_LIBDIR" environment variable. > > To ease this, some distributions provide <triplet>-pkg-config > (for example, aarch64-linux-gnu-pkg-config). > This became the nationale for tools/build/feature/Makefile defining: > > PKG_CONFIG ?= $(CROSS_COMPILE)pkg-config > > But, this wrapper shell script is not always available. > I do not know how to do it with the LLVM tool suite. > I am not quite sure if this is the global solution. > > > These days, pkgconf supports another way, .personality file [4] > to specify the .pc search paths for cross builds. > > Is it reasonable to use an option to distinguish native / cross builds > and use the same macro "PKG_CONFIG = pkg-config" everywhere ? > > > [4] http://manpages.ubuntu.com/manpages/focal/en/man5/pkgconf-personality.5.html I'm not sure, but do we need to cross that bridge for this patch if it's just adding support for the HOST? No cross pkg-config necessary, yet. (Famous last words). -- Thanks, ~Nick Desaulniers
