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

Taylor Simpson posted 29 patches 5 years, 4 months ago
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RE: [RFC PATCH v4 00/29] Hexagon patch series
Posted by Taylor Simpson 5 years, 4 months ago 

> -----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
Re: [RFC PATCH v4 00/29] Hexagon patch series
Posted by Philippe Mathieu-Daudé 5 years, 4 months ago 
Cc'ing Eric/Thomas...

On 9/29/20 10:11 PM, Taylor Simpson wrote:
>> -----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
>
Re: [RFC PATCH v4 00/29] Hexagon patch series
Posted by Eric Blake 5 years, 4 months ago 
On 9/29/20 3:11 PM, Taylor Simpson wrote:

> 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)

See if you can use __builtin_choose_expr() instead.  Look at
include/osdep/atomic.h which defines typeof_strip_qual() without
_Generic.  linux-user/qemu.h __put_user_e() is also an example of what
appears to be a poor-man's replacement to _Generic.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org
RE: [RFC PATCH v4 00/29] Hexagon patch series
Posted by Taylor Simpson 5 years, 4 months ago 
> -----Original Message-----
> From: Eric Blake <eblake@redhat.com>
> Sent: Tuesday, September 29, 2020 3:29 PM
> To: Taylor Simpson <tsimpson@quicinc.com>; Philippe Mathieu-Daudé
> <f4bug@amsat.org>; 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
>
> On 9/29/20 3:11 PM, Taylor Simpson wrote:
>
> > 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)
>
> See if you can use __builtin_choose_expr() instead.  Look at
> include/osdep/atomic.h which defines typeof_strip_qual() without
> _Generic.  linux-user/qemu.h __put_user_e() is also an example of what
> appears to be a poor-man's replacement to _Generic.

Thanks!  It's a pretty straightforward translation for my use cases

#define MEM_STORE1_FUNC(X) \
    __builtin_choose_expr(__builtin_types_compatible_p(typeof(X), int), \
        gen_store1i, \
        gen_store1)
#define MEM_STORE1(VA, DATA, SLOT) \
    MEM_STORE1_FUNC(DATA)(cpu_env, VA, DATA, ctx, SLOT)


Taylor

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