RE: [RFC PATCH v4 00/29] Hexagon patch series

[Taylor Simpson]

> -----Original Message-----
> From: Philippe Mathieu-Daudé <philippe.mathieu.daude@gmail.com> On
> Behalf Of Philippe Mathieu-Daudé
> Sent: Tuesday, September 29, 2020 11:02 AM
> To: Taylor Simpson <tsimpson@quicinc.com>; qemu-devel@nongnu.org
> Cc: ale@rev.ng; riku.voipio@iki.fi; richard.henderson@linaro.org;
> laurent@vivier.eu; aleksandar.m.mail@gmail.com
> Subject: Re: [RFC PATCH v4 00/29] Hexagon patch series
>
> QEMU aims to support the 2 latest releases of supported distributions.
> From time to time a brave developer look at the different versions
> packaged and make some cleanup in the code base. It used to be tedious,
> now that repology.org exists it is a bit easier.
>
> The last effort is from Thomas, see commit efc6c070aca:
>
>     The supported distributions use the following version
>     of GCC:
>
>           RHEL-7: 4.8.5
>           Debian (Stretch): 6.3.0
>           Debian (Jessie): 4.8.4
>           OpenBSD (ports): 4.9.4
>           FreeBSD (ports): 8.2.0
>           OpenSUSE Leap 15: 7.3.1
>           Ubuntu (Xenial): 5.3.1
>           macOS (Homebrew): 8.2.0
>
>     So we can safely assume GCC 4.8 these days.
>
> This is the "mandated" compiler version.

Ouch!  4.8 is old enough that it doesn't support C11 _Generic which I am using. 
 That needs at least GCC 4.9.

Here are a couple of examples.  As you can see, _Generic is used to dispatch to 
slightly different TCG generation functions depending on the type of the 
operands.  I will scratch my head and figure out a different way to do this.

#define MEM_STORE1_FUNC(X) \
    _Generic((X), int : gen_store1i, TCGv_i32 : gen_store1)
#define MEM_STORE1(VA, DATA, SLOT) \
    MEM_STORE1_FUNC(DATA)(cpu_env, VA, DATA, ctx, SLOT)

#define GETBYTE_FUNC(X) \
    _Generic((X), TCGv_i32 : gen_get_byte, TCGv_i64 : gen_get_byte_i64)
#define fGETBYTE(N, SRC) GETBYTE_FUNC(SRC)(BYTE, N, SRC, true)
#define fGETUBYTE(N, SRC) GETBYTE_FUNC(SRC)(BYTE, N, SRC, false)


FWIW, I have been using 5.5.

The errors you saw started around 7.5 and are easy to fix.


Taylor