Re: [PATCH] tools/ocaml: Factor out compatiblity handling

[Christian Lindig <christian.lindig@xxxxxxxxx>]

> On 28 Aug 2024, at 14:30, Andrew Cooper <Andrew.Cooper3@xxxxxxxxxx> wrote:
> 
> ... rather than having each library implement its own subset.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> ---
> CC: Christian Lindig <christian.lindig@xxxxxxxxxx>
> CC: David Scott <dave@xxxxxxxxxx>
> CC: Edwin Török <edwin.torok@xxxxxxxxx>
> CC: Rob Hoes <Rob.Hoes@xxxxxxxxxx>
> CC: Andrii Sultanov <andrii.sultanov@xxxxxxxxx>
> 
> Broken out of a larger series, to help Andrii with his dynlib work.
> ---
> tools/ocaml/libs/xc/Makefile        |  2 +-
> tools/ocaml/libs/xc/xenctrl_stubs.c | 13 +++----------
> tools/ocaml/libs/xen-caml-compat.h  | 23 +++++++++++++++++++++++
> 3 files changed, 27 insertions(+), 11 deletions(-)
> create mode 100644 tools/ocaml/libs/xen-caml-compat.h
> 
> diff --git a/tools/ocaml/libs/xc/Makefile b/tools/ocaml/libs/xc/Makefile
> index 1d9fecb06ef2..cdf4d01dac52 100644
> --- a/tools/ocaml/libs/xc/Makefile
> +++ b/tools/ocaml/libs/xc/Makefile
> @@ -2,7 +2,7 @@ OCAML_TOPLEVEL=$(CURDIR)/../..
> XEN_ROOT=$(OCAML_TOPLEVEL)/../..
> include $(OCAML_TOPLEVEL)/common.make
> 
> -CFLAGS += -I../mmap $(CFLAGS_libxenctrl) $(CFLAGS_libxenguest)
> +CFLAGS += -I../ -I../mmap $(CFLAGS_libxenctrl) $(CFLAGS_libxenguest)
> CFLAGS += $(APPEND_CFLAGS)
> OCAMLINCLUDE += -I ../mmap -I ../eventchn
> 
> diff --git a/tools/ocaml/libs/xc/xenctrl_stubs.c 
> b/tools/ocaml/libs/xc/xenctrl_stubs.c
> index a52908012960..c78191f95abc 100644
> --- a/tools/ocaml/libs/xc/xenctrl_stubs.c
> +++ b/tools/ocaml/libs/xc/xenctrl_stubs.c
> @@ -25,6 +25,8 @@
> #include <caml/fail.h>
> #include <caml/callback.h>
> 
> +#include "xen-caml-compat.h"
> +
> #include <sys/mman.h>
> #include <stdint.h>
> #include <string.h>
> @@ -37,14 +39,6 @@
> 
> #include "mmap_stubs.h"
> 
> -#ifndef Val_none
> -#define Val_none (Val_int(0))
> -#endif
> -
> -#ifndef Tag_some
> -#define Tag_some 0
> -#endif
> -
> static inline xc_interface *xch_of_val(value v)
> {
> xc_interface *xch = *(xc_interface **)Data_custom_val(v);
> @@ -744,8 +738,7 @@ CAMLprim value stub_xc_evtchn_status(value xch_val, value 
> domid, value port)
> Store_field(result_status, 0, Val_int(status.vcpu));
> Store_field(result_status, 1, stat);
> 
> - result = caml_alloc_small(1, Tag_some);
> - Store_field(result, 0, result_status);
> + result = caml_alloc_some(result_status);
> 
> CAMLreturn(result);
> }
> diff --git a/tools/ocaml/libs/xen-caml-compat.h 
> b/tools/ocaml/libs/xen-caml-compat.h
> new file mode 100644
> index 000000000000..b4a0ca4ce90c
> --- /dev/null
> +++ b/tools/ocaml/libs/xen-caml-compat.h
> @@ -0,0 +1,23 @@
> +/* SPDX-License-Identifier: LGPL-2.1-only WITH OCaml-LGPL-linking-exception 
> */
> +#ifndef XEN_CAML_COMPAT_H
> +#define XEN_CAML_COMPAT_H
> +
> +#ifndef Val_none /* Option handling.  Compat for Ocaml < 4.12 */
> +
> +#define Val_none Val_int(0)
> +#define Tag_some 0
> +#define Some_val(v) Field(v, 0)
> +
> +static inline value caml_alloc_some(value v)
> +{
> +    CAMLparam1(v);
> +
> +    value some = caml_alloc_small(1, Tag_some);
> +    Store_field(some, 0, v);
> +
> +    CAMLreturn(some);
> +}
> +
> +#endif /* !Val_none */
> +
> +#endif /* XEN_CAML_COMPAT_H */
> 
> base-commit: 75c64db3722f0245137a1e8cfd3435f4790d0fd7
> -- 
> 2.39.2
> 

Acked-by: Christian Lindig <christian.lindig@xxxxxxxxx>