Re: [PATCH v2 01/15] RISC-V: Build Infastructure

[Joseph Myers <joseph at codesourcery dot com>]

On Tue, 19 Dec 2017, Palmer Dabbelt wrote:

> diff --git a/sysdeps/riscv/Makefile b/sysdeps/riscv/Makefile
> new file mode 100644
> index 000000000000..64060531a1d5
> --- /dev/null
> +++ b/sysdeps/riscv/Makefile
> @@ -0,0 +1,49 @@
> +ifneq ($(all-rtld-routines),)
> +CFLAGS-rtld.c += -mno-plt

My previous comments from 
<https://sourceware.org/ml/libc-alpha/2017-06/msg00645.html> still apply: 
this is too fragile (people won't think when making an 
architecture-independent change about whether it needs a RISC-V-specific 
change here) and completely lacking the required detailed explanatory 
comment of what the issue is and the logic for determining what files need 
this option (but really the logic should be implemented to avoid an 
architecture-specific list of architecture-independent files being needed 
at all).

> diff --git a/sysdeps/riscv/Versions b/sysdeps/riscv/Versions
> new file mode 100644
> index 000000000000..aafa348a2395
> --- /dev/null
> +++ b/sysdeps/riscv/Versions
> @@ -0,0 +1,4 @@
> +libc {
> +  GLIBC_2.27 {
> +  }
> +}

You shouldn't need this file at all when there aren't any versions to 
include in it.

> diff --git a/sysdeps/riscv/preconfigure b/sysdeps/riscv/preconfigure

Does your soft-float lack support for exceptions and rounding modes?  If 
so, I'd expect a setting of with_fp_cond, and a corresponding nofpu 
directory or directories with Implies files pointing to ieee754/soft-fp 
(arranged so that always comes before the other ieee754/ directories in 
the sysdeps directory ordering).  That's needed to get the soft-fp 
versions of fmaf/fma/fmal used instead of the default ones relying on 
exceptions and rounding modes, so its absence should show up as test 
failures for soft-float configurations.  In future it will also similarly 
be needed to get soft-fp versions of TS 18661-1 narrowing functions used.

Remark: it makes sense for ieee754/dbl-64/wordsize-64 to be used (before 
ieee754/dbl-64 in the sysdeps directory ordering) in configurations with 
64-bit registers (but that's just an optimization so you may wish to defer 
it).

> +abi-ilp32-options     := -D__SIZEOF_INT__=4

abi-* options variables are no longer used with the current bits/syscall.h 
generation mechanism, so you should remove all settings of such variables 
from the patch.

> diff --git a/sysdeps/unix/sysv/linux/riscv/rv64/Makefile b/sysdeps/unix/sysv/linux/riscv/rv64/Makefile
> new file mode 100644
> index 000000000000..cb60d740476d
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/riscv/rv64/Makefile
> @@ -0,0 +1,4 @@
> +ifeq ($(subdir),socket)
> +CFLAGS-recv.c += -fexceptions
> +CFLAGS-send.c += -fexceptions
> +endif

I wonder if this should be made generic for all Linux ports (and removed 
from the mips64 Makefile as well as here).

-- 
Joseph S. Myers
joseph@codesourcery.com