[PATCH v5 3/6] firmware: Explicitly pass -pie to the linker, not just the driver

[Bin Meng]

On Sun, Jul 11, 2021 at 9:06 PM Jessica Clarke <jrtc27 at jrtc27.com> wrote:
>
> On 11 Jul 2021, at 14:05, Bin Meng <bmeng.cn at gmail.com> wrote:
> >
> > On Sun, Jul 11, 2021 at 10:29 AM Jessica Clarke <jrtc27 at jrtc27.com> wrote:
> >>
> >> When using Clang with a bare-metal triple, -pie does not get passed to
> >> the linker as it's not normally a thing that makes sense, unlike GCC
> >> which will unconditionally forward it on and potentially result in a
> >
> > It seems GCC driver does not unconditionally forward it to the linker, see:
> >
> > $ riscv64-unknown-elf-gcc -fPIE -nostdlib -x c /dev/null -o /dev/null
> > 2>&1 && echo y
> > /opt/riscv-unknown-elf/lib/gcc/riscv64-unknown-elf/10.1.0/../../../../riscv64-unknown-elf/bin/ld:
> > warning: cannot find entry symbol _start; defaulting to
> > 0000000000010040
> > y
> >
> > But
> >
> > $ riscv64-unknown-elf-gcc -fPIE -nostdlib -Wl,-pie -x c /dev/null -o
> > /dev/null 2>&1 && echo y
> > /opt/riscv-unknown-elf/lib/gcc/riscv64-unknown-elf/10.1.0/../../../../riscv64-unknown-elf/bin/ld:
> > -pie not supported
> > collect2: error: ld returned 1 exit status
> >
> > So regarding bare-metal triple, GCC driver and  clang driver behave
> > the same way. It's just GNU bare-metal ld does not support PIE, while
> > LLD supports.
> >
> > So we need to revise the above commit message.
>
> You didn’t pass -pie, only -fPIE.

Ah, yes. Indeed -pie is the linker option. Then we are good.

Regards,
Bin