Re: [PATCH] tools/ocaml/Makefile.rules: use correct C flags when compiling OCaml C stubs

[Christian Lindig <christian.lindig@xxxxxxxxx>]

> On 25 Oct 2023, at 14:52, Edwin Török <edvin.torok@xxxxxxxxxx> wrote:
> 
> From: Edwin Török <edwin.torok@xxxxxxxxx>
> 
> The code currently uses GCC to compile OCaml C stubs directly,
> and although in most cases this works, it is not entirely correct.
> 
> This will fail if the OCaml runtime has been recompiled to use and link with 
> ASAN for example
> (or other situations where a flag needs to be used consistently in everything 
> that is linked into the same binary).
> 
> Use the OCaml compiler instead, which knows how to invoke the correct C 
> compiler with the correct flags,
> and append the Xen specific CFLAGS to that instead.
> 
> Drop the explicit -fPIC and -I$(ocamlc -where): these will now be provided by 
> the compiler as needed.
> 
> Use -verbose so we see the actuall full C compiler command line invocation 
> done by the OCaml compiler.
> 
> Signed-off-by: Edwin Török <edwin.torok@xxxxxxxxx>

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

I like using the OCaml compiler to compile stubs as it knows how to handle C 
files and will invoke the C compiler with the correct flags. However, this is 
the kind of change that would be good to have tested on all supported 
platforms. I therefore invite comments from those who maintain the build 
process.

— C