> -----Original Message----- > From: Thomas Monjalon <tho...@monjalon.net> > Sent: Wednesday, January 20, 2021 11:35 AM > To: Juraj Linkeš <juraj.lin...@pantheon.tech> > Cc: david.march...@redhat.com; acon...@redhat.com; > maicolgabr...@hotmail.com; jerinjac...@gmail.com; ferruh.yi...@intel.com; > ruifeng.w...@arm.com; dev@dpdk.org; bruce.richard...@intel.com > Subject: Re: [dpdk-dev] [PATCH v4 1/3] build: add aarch64 clang to meson > cross- > compile > > 20/01/2021 11:30, Juraj Linkeš: > > From: Thomas Monjalon <tho...@monjalon.net> > > > 20/01/2021 09:24, Juraj Linkeš: > > > > From: Thomas Monjalon <tho...@monjalon.net> > > > > > 19/01/2021 09:33, Juraj Linkeš: > > > > > > Create meson cross-file arm64_armv8_linux_clang_ubuntu1804. > > > > > > > > > > Why is it specific to Ubuntu 18.04? > > > > > I don't want to add specifc cross files per distributions. > > > > > > > > > > > Use clang/LLVM toolchain with sysroot pointing to gcc cross stdlib. > > > > > > > > > > > > The sysroot path must be in the cross-file so that Clang can > > > > > > find the proper headers: > > > > > > * setting CFLAGS, LDFLAGS or -Dc_args, -Dc_link_args doesn't > > > > > > affect cross builds (only native builds). Support added in 0.51.0. > > > > > > * setting pkg-config vars only affects lib searching, not > > > > > > includes > > > > > > * splitting the cross-file into two (one with clang info, one > > > > > > with > > > > > > paths) doesn't work. Support added in 0.52.0. > > > > > > > > > > I don't understand the explanations above. > > > > > Please explain what is the bug and how it is fixed. > > > > > > > > > > > > > I guess the missing piece is that the sysroot path is the ubuntu > > > > specific part. > > > The explanations illustrate why we can't have a generic cross file > > > with the current meson version - there's no way to pass the paths to > > > cross builds. Now that I think about it, the commit message needs a > > > rewrite - I should've mentioned that clang/llvm doesn't provide it's > > > own standard c lib, so that has to come from elsewhere (such as gcc) and > thus we have to provide the paths. > > > > > > Can it be done with the option -Dc_args? > > > > > > > Not in Meson 0.47.1, it's explained in the commit msg: > > * setting CFLAGS, LDFLAGS or -Dc_args, -Dc_link_args doesn't affect > > cross builds (only native builds). Support added in 0.51.0. > > So I suggest to make it clearer :) > One proposal: > > * setting CFLAGS/LDFLAGS variables or using -Dc_args/-Dc_link_args options > do not work on cross builds until Meson 0.51.0. >
Ok, I'll reword the commit message to make it more clearer based on your feedback. > > > > > [...] > > > > > > +c_args = ['-target', 'aarch64-linux-gnu', '--sysroot', > > > > > > +'/usr/aarch64-linux-gnu'] c_link_args = ['-target', > > > > > > +'aarch64-linux-gnu', '-fuse-ld=lld', '--gcc-toolchain=/usr'] > > > > > > > > > > > > > > > > > >
