Committed with following changes:
- Rename --with-multilib-config to --with-multilib-generator.
- Check --with-multilib-generator and --with-multilib-list can't be
used at same time.
- Fix doc.
On Wed, Oct 28, 2020 at 3:01 AM Jim Wilson <j...@sifive.com> wrote:
>
> On Mon, Oct 19, 2020 at 2:35 AM Kito Cheng <kito.ch...@sifive.com> wrote:
>
> > - I was consider to implmenet this into `--with-multilib-list` option,
> > but I am not sure who will using that with riscv*-*-elf*, so I decide to
> > using another option name for that.
> >
>
> I believe that --with-multllib-list is only useful for linux targets. I
> added it to fix a problem with one of the distros. They needed to enable
> multilibs to get the right paths that they wanted at install time, but
> since we don't support native ilp32 builds on rv64 yet, they needed to be
> able to specify that only one multilib gets built. So that is what the
> RISC-V --with-multilib-list is for, and it only allows one multilib to be
> selected.
>
> Since you have these as separate options, I think using both
> --with-multilib-list and --with-multilib-config should be a configure
> error. At least for RISC-V this doesn't do anything meaningful, two t-*
> files get included, and the second one t-withmultilib overrides the first
> one t-withmultilib-config, so the --with-multilib-config option does
> nothing, regardless of what order you specify the two options. Note that
> t-withmultilib sets MULTILIB_OSDIRNAMES and t-withmultilib-config does not,
> so we would get a confused result if they were included in the other
> order. Linux targets need MULTILIB_OSDIRNAMES for embedded elf targets do
> not. Anyways, it is simpler to just not allow both configure options to be
> used at the same time.
>
> > - --with-multilib-config will pass arguments to multilib-generator, and
> > then using the generated multi-lib config file to build the toolchain.
> >
> > e.g. Build riscv gcc, default arch/abi is rv64gc/lp64, and build multilib
> > for rv32imafd/ilp32 and rv32i/ilp32; rv32ic/ilp32 will reuse
> > rv32i/ilp32.
> > $ <GCC-SRC>/configure \
> > --target=riscv64-elf \
> > --with-arch=rv64gc --with-abi=lp64 \
> > --with-multilib-config=rv32i-ilp32--c;rv32imafd-ilp32--
> >
>
> Overall looks OK to me, and very useful, though RISC-V specific, since the
> syntax used is specific to the RISC-V multilib generator. We do have a
> number of target dependent configure options though, like --with-lxc1-sxc1
> for MIPS and --with-aix-soname= for AIX, so I don't think this should be a
> problem. Unless maybe we want a clearer name, like maybe
> --with-multilib-generator, to indicate that it requires a script to
> generate the multilibs.
>
> diff --git a/gcc/doc/install.texi b/gcc/doc/install.texi
> > index 5330bf3bb293..2972dcad7c26 100644
> > --- a/gcc/doc/install.texi
> > +++ b/gcc/doc/install.texi
> > @@ -1252,6 +1252,36 @@ If @option{--with-multilib-list} is not given, then
> > only 32-bit and
> > 64-bit run-time libraries will be enabled.
> > @end table
> >
> > +@item --with-multilib-config=@var{config}
> > +Specify what multilibs to build. @var{config} is a semicolon separated
> > list of
> > +values, possibly consisting of a single value. Currently only implemented
> > +for riscv*-*-elf*. The accepted values and meaning is given below.
> >
>
> The accepted values and meanings are given below.
>
> > +
> > +Every config is construct with four components: architecture string, ABI,
> > +reuse rule with architecture string and reuse rule with sub-extension.
> >
>
> Every config is constructed with ...
>
> Other than the question of whether we maybe want to rename the configure
> option, and some minor english improvements, this is OK.
> Jim
