[Bug sim/29752] New: Build failure with upcoming Clang 16 (-Wincompatible-function-pointer-types, -Wimplicit-function-declaration)

[Bug sim/29752] New: Build failure with upcoming Clang 16 (-Wincompatible-function-pointer-types, -Wimplicit-function-declaration)

[sam at gentoo dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=29752

            Bug ID: 29752
           Summary: Build failure with upcoming Clang 16
                    (-Wincompatible-function-pointer-types,
                    -Wimplicit-function-declaration)
           Product: gdb
           Version: unknown
            Status: NEW
          Severity: normal
          Priority: P2
         Component: sim
          Assignee: unassigned at sourceware dot org
          Reporter: sam at gentoo dot org
                CC: vapier at gentoo dot org
  Target Milestone: ---

Created attachment 14434
  --> https://sourceware.org/bugzilla/attachment.cgi?id=14434&action=edit
build.log.xz (12.1)

Clang 16 will make -Wimplicit-function-declaration, -Wimplicit-int,
-Wincompatible-function-pointer-declarations error by default.

You can emulate its behaviour _mostly_ by just setting those in your *FLAGS.

GDB 12 seems to have quite a large number of failures with Clang 16,
unfortunately :(

Originally reported downstream in Gentoo at https://bugs.gentoo.org/871543.

For more information, see LWN.net [0] or LLVM's Discourse [1], gentoo-dev@ [2],
or the (new) c-std-porting mailing list [3].

[0] https://lwn.net/Articles/913505/
[1]
https://discourse.llvm.org/t/configure-script-breakage-with-the-new-werror-implicit-function-declaration/65213
[2]
https://archives.gentoo.org/gentoo-dev/message/dd9f2d3082b8b6f8dfbccb0639e6e240
[3] hosted at lists.linux.dev.

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[Bug sim/29752] Build failure with upcoming Clang 16 (-Wincompatible-function-pointer-types, -Wimplicit-function-declaration)

[sam at gentoo dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=29752

--- Comment #1 from Sam James <sam at gentoo dot org> ---
Created attachment 14435
  --> https://sourceware.org/bugzilla/attachment.cgi?id=14435&action=edit
build.log.xz ("9999", master at 25e64b5276487ac8d95fc5030a1ba626883c7afd)

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[Bug sim/29752] Build failure with upcoming Clang 16 (-Wincompatible-function-pointer-types, -Wimplicit-function-declaration)

[vapier at gentoo dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=29752

--- Comment #2 from Mike Frysinger <vapier at gentoo dot org> ---
there's a couple of people already working on building things with clang.  it's
def not a priority, so i don't think it'll be fixed by GDB 13.

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[Bug sim/29752] Build failure with upcoming Clang 16 (-Wincompatible-function-pointer-types, -Wimplicit-function-declaration)

[sam at gentoo dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=29752

--- Comment #3 from Sam James <sam at gentoo dot org> ---
Sure. Just note that GCC 14 is likely to make two of these changes anyway
(-Wimplicit-function-declaration and -Wimplicit-int).

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[Bug sim/29752] sim: build failure with Clang 16 (-Wincompatible-function-pointer-types, -Wimplicit-function-declaration)

[vapier at gentoo dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=29752

Mike Frysinger <vapier at gentoo dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|Build failure with upcoming |sim: build failure with
                   |Clang 16                    |Clang 16
                   |(-Wincompatible-function-po |(-Wincompatible-function-po
                   |inter-types,                |inter-types,
                   |-Wimplicit-function-declara |-Wimplicit-function-declara
                   |tion)                       |tion)

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[Bug sim/29752] sim: build failure with Clang 16 (-Wincompatible-function-pointer-types, -Wimplicit-function-declaration)

[vapier at gentoo dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=29752

--- Comment #4 from Mike Frysinger <vapier at gentoo dot org> ---
considering GCC 13 probably won't be released for another ~6 months, and GCC 14
another ~year after that (~Apr 2024), i think we have plenty of time.  no need
to rush to get things into GDB 13 that should be cut any day now.

(ftr, GDB 13 candidates build fine with current GCC 13 snapshots)

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[Bug sim/29752] sim: build failure with Clang 16 (-Wincompatible-function-pointer-types, -Wimplicit-function-declaration)

[simark at simark dot ca]

https://sourceware.org/bugzilla/show_bug.cgi?id=29752

Simon Marchi <simark at simark dot ca> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |simark at simark dot ca

--- Comment #5 from Simon Marchi <simark at simark dot ca> ---
Also, releases, build without -Werror by default, so it's not the end of the
world if there are benign warnings in releases.

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[Bug sim/29752] sim: build failure with Clang 16 (-Wincompatible-function-pointer-types, -Wimplicit-function-declaration)

[sam at gentoo dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=29752

--- Comment #6 from Sam James <sam at gentoo dot org> ---
> On 9 Nov 2022, at 15:38, simark at simark dot ca <sourceware-bugzilla@sourceware.org> wrote:
> 
> https://sourceware.org/bugzilla/show_bug.cgi?id=29752
> 
> Simon Marchi <simark at simark dot ca> changed:
> 
>           What    |Removed                     |Added
> ----------------------------------------------------------------------------
>                 CC|                            |simark at simark dot ca
> 
> --- Comment #5 from Simon Marchi <simark at simark dot ca> ---
> Also, releases, build without -Werror by default, so it's not the end of the
> world if there are benign warnings in releases.
> 

They become errors by default. Not building with -Werror doesn't make a
difference. You have to specifically negate it with -Wno... if you want to do
that.

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[Bug sim/29752] sim: build failure with Clang 16 (-Wincompatible-function-pointer-types, -Wimplicit-function-declaration)

[simark at simark dot ca]

https://sourceware.org/bugzilla/show_bug.cgi?id=29752

--- Comment #7 from Simon Marchi <simark at simark dot ca> ---
Ok, I re-read you original message and I understand what you mean.  That's odd
for compilers to decide for some diagnostics not to follow -W(no-)error.

We currently add -Werror when development mode is on, that is outside of
releases.  We should perhaps use -Wno-error when development mode is off then.

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[Bug sim/29752] sim: build failure with Clang 16 (-Wincompatible-function-pointer-types, -Wimplicit-function-declaration)

[sam at gentoo dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=29752

--- Comment #8 from Sam James <sam at gentoo dot org> ---
(In reply to Mike Frysinger from comment #4)
gcc 14 now does this, to be released in april 2024 or so indeed

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[Bug sim/29752] sim:frv: -Wincompatible-function-pointer-types build failure: sem.c:24343:41: error: incompatible function pointer types passing 'void (SIM_CPU *, UINT, UDI)' to parameter of type 'void (*)(SIM_CPU *, UINT, DI)'

[vapier at gentoo dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=29752

Mike Frysinger <vapier at gentoo dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|sim: build failure with     |sim:frv:
                   |Clang 16                    |-Wincompatible-function-poi
                   |(-Wincompatible-function-po |nter-types build failure:
                   |inter-types,                |sem.c:24343:41: error:
                   |-Wimplicit-function-declara |incompatible function
                   |tion)                       |pointer types passing 'void
                   |                            |(SIM_CPU *, UINT, UDI)' to
                   |                            |parameter of type 'void
                   |                            |(*)(SIM_CPU *, UINT, DI)'
             Target|                            |frv-elf

--- Comment #9 from Mike Frysinger <vapier at gentoo dot org> ---
i think all -Wimplicit-function-declaration issues are fixed

the only -Wincompatible-function-pointer-types issue left is frv and its
sem.c/queue logic.

sem.c:24343:41: error: incompatible function pointer types passing 'void
(SIM_CPU *, UINT, UDI)' (aka 'void (struct _sim_cpu *, unsigned int, unsigned
long)') to parameter of type 'void (*)(SIM_CPU *, UINT, DI)' (aka 'void
(*)(struct _sim_cpu *, unsigned int, long)')
[-Wincompatible-function-pointer-types]

sem.c is generated by CGEN code.  not really sure where in the scheme files
this comes from.  but it's all related to a call like:
  sim_queue_fn_di_write (current_cpu, frvbf_h_acc40U_set, ...

sim_queue_fn_di_write wants a func that has a param of (SIM_CPU*, UINT, DI),
but frvbf_h_acc40U_set has a UDI.  there isn't a sim_queue_fn_udi_write helper.

we could change frvbf_h_acc40U_set to take a DI instead of UDI ?  in practice,
i don't think the sign is checked ?  not sure tbh.  and we don't have much of
an FRV maintainer atm.

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[Bug sim/29752] sim:frv: -Wincompatible-function-pointer-types build failure: sem.c:24343:41: error: incompatible function pointer types passing 'void (SIM_CPU *, UINT, UDI)' to parameter of type 'void (*)(SIM_CPU *, UINT, DI)'

[vapier at gentoo dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=29752

--- Comment #10 from Mike Frysinger <vapier at gentoo dot org> ---
this change (and regenerating the files) fixes the warnings.

--- a/cpu/frv.cpu
+++ b/cpu/frv.cpu
@@ -2933,7 +2933,7 @@
   (name h-acc40U)
   (comment "40 bit unsigned accumulator")
   (attrs PROFILE VIRTUAL)
-  (type register UDI (64))
+  (type register DI (64))
   (indices extern-keyword acc-names)
   ; The accumlator is made up of two 32 bit registers, accgi/acci.
   ; We want to extract this as a combined 40 unsigned bits

but not sure at all about the ramifications of it on the port.

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[Bug sim/29752] sim:frv: -Wincompatible-function-pointer-types build failure: sem.c:24343:41: error: incompatible function pointer types passing 'void (SIM_CPU *, UINT, UDI)' to parameter of type 'void (*)(SIM_CPU *, UINT, DI)'

[mark at klomp dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=29752

Mark Wielaard <mark at klomp dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |mark at klomp dot org

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[Bug sim/29752] sim:frv: -Wincompatible-function-pointer-types build failure: sem.c:24343:41: error: incompatible function pointer types passing 'void (SIM_CPU *, UINT, UDI)' to parameter of type 'void (*)(SIM_CPU *, UINT, DI)'

[vapier at gentoo dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=29752

Mike Frysinger <vapier at gentoo dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at sourceware dot org   |brolley at redhat dot com

--- Comment #11 from Mike Frysinger <vapier at gentoo dot org> ---
forgot to loop in frv maintainer

considering we're looking at a hard build failure here with newer compilers
(where we can't turn it off with -W flags), i'm inclined to merge my patch in
comment #10 (and with regenerated files).  the unittests still pass, but i have
no idea whether they provide coverage in this particular area.

next gdb branch is schedule for Apr, so i'll move forward with my patch in Feb
if no one has a better idea.

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[Bug sim/29752] sim:frv: -Wincompatible-function-pointer-types build failure: sem.c:24343:41: error: incompatible function pointer types passing 'void (SIM_CPU *, UINT, UDI)' to parameter of type 'void (*)(SIM_CPU *, UINT, DI)'

[mark at klomp dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=29752

--- Comment #12 from Mark Wielaard <mark at klomp dot org> ---
(In reply to Mike Frysinger from comment #11)
> forgot to loop in frv maintainer

I am afraid that email address hasn't been valid for 5 years. And the new
address I have (from 2018) doesn't seem attached to a bugzilla account. I'll
try emailing Dave.

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[Bug sim/29752] sim:frv: -Wincompatible-function-pointer-types build failure: sem.c:24343:41: error: incompatible function pointer types passing 'void (SIM_CPU *, UINT, UDI)' to parameter of type 'void (*)(SIM_CPU *, UINT, DI)'

[vapier at gentoo dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=29752

Mike Frysinger <vapier at gentoo dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |nickc at redhat dot com

--- Comment #13 from Mike Frysinger <vapier at gentoo dot org> ---
i was using the e-mail address listed in MAINTAINERS files :/

i assume frv is being maintained at Redhat via some contract, and Dave was
listed because of that rather than personal passion for frv :).  is there
someone new at Redhat who is responsible for it ?  Nick is about the only other
person i'd guess might know more.

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[Bug sim/29752] sim:frv: -Wincompatible-function-pointer-types build failure: sem.c:24343:41: error: incompatible function pointer types passing 'void (SIM_CPU *, UINT, UDI)' to parameter of type 'void (*)(SIM_CPU *, UINT, DI)'

[fche at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=29752

Frank Ch. Eigler <fche at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |fche at redhat dot com

--- Comment #14 from Frank Ch. Eigler <fche at redhat dot com> ---
Go ahead with the UDI->DI change.  If the code builds, and still passes
simulator smoke tests, it should be fine.

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[Bug sim/29752] sim:frv: -Wincompatible-function-pointer-types build failure: sem.c:24343:41: error: incompatible function pointer types passing 'void (SIM_CPU *, UINT, UDI)' to parameter of type 'void (*)(SIM_CPU *, UINT, DI)'

[vapier at gentoo dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=29752

Mike Frysinger <vapier at gentoo dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

--- Comment #15 from Mike Frysinger <vapier at gentoo dot org> ---
ok, pushed then, thx for checking

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