Re: [Qemu-devel] [PATCH v4 2/3] ppc: Drop duplicated typedefs to be able to compile with Clang in gnu99 mode

[Greg Kurz <groug@kaod.org>]

On Thu, 10 Jan 2019 10:15:35 +0100
Thomas Huth <thuth@redhat.com> wrote:

> When compiling the ppc code with clang and -std=gnu99, there are a
> couple of warnings/errors like this one:
> 
>   CC      ppc64-softmmu/hw/intc/xics.o
> In file included from /home/thuth/devel/qemu/hw/intc/xics.c:35:
> /home/thuth/devel/qemu/include/hw/ppc/xics.h:43:25: error: redefinition of typedef 'ICPState' is a C11 feature
>       [-Werror,-Wtypedef-redefinition]
> typedef struct ICPState ICPState;
>                         ^
> /home/thuth/devel/qemu/target/ppc/cpu.h:1181:25: note: previous definition is here
> typedef struct ICPState ICPState;
>                         ^
> 
> Drop the duplicated typedefs and use normal "struct" forward declarations
> like we already do it at the top of spapr.h for a couple of other definitions.
> 

Hmm... so the choice here is to simply ignore the official coding
style ?

It is a bit confusing to end up with even more struct/non-struct
inconsistency. It would be good at least to update HACKING so that
people know when they can legitimately do that... or we simply don't
care anymore for the typedef rule ?

All these forward declarations could be typedefs in a "hw/ppc/spapr_types.h"
header as well, as suggested elsewhere by Daniel.

> Signed-off-by: Thomas Huth <thuth@redhat.com>
> ---
>  include/hw/ppc/spapr.h      | 9 +++++----
>  include/hw/ppc/spapr_xive.h | 3 +--
>  target/ppc/cpu.h            | 9 +++++----
>  3 files changed, 11 insertions(+), 10 deletions(-)
> 
> diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> index 9e01a5a..10d069e 100644
> --- a/include/hw/ppc/spapr.h
> +++ b/include/hw/ppc/spapr.h
> @@ -12,11 +12,12 @@
>  struct VIOsPAPRBus;
>  struct sPAPRPHBState;
>  struct sPAPRNVRAM;
> +struct ICSState;
> +struct sPAPRXive;
> +
>  typedef struct sPAPREventLogEntry sPAPREventLogEntry;
>  typedef struct sPAPREventSource sPAPREventSource;
>  typedef struct sPAPRPendingHPT sPAPRPendingHPT;
> -typedef struct ICSState ICSState;

Thanks to the previous patch, I guess the ICSState type could be
obtained by including "hw/ppc/xics.h".

> -typedef struct sPAPRXive sPAPRXive;
>  
>  #define HPTE64_V_HPTE_DIRTY     0x0000000000000040ULL
>  #define SPAPR_ENTRY_POINT       0x100
> @@ -127,7 +128,7 @@ struct sPAPRMachineState {
>      struct VIOsPAPRBus *vio_bus;
>      QLIST_HEAD(, sPAPRPHBState) phbs;
>      struct sPAPRNVRAM *nvram;
> -    ICSState *ics;
> +    struct ICSState *ics;
>      sPAPRRTCState rtc;
>  
>      sPAPRResizeHPT resize_hpt;
> @@ -180,7 +181,7 @@ struct sPAPRMachineState {
>      const char *icp_type;
>      int32_t irq_map_nr;
>      unsigned long *irq_map;
> -    sPAPRXive  *xive;
> +    struct sPAPRXive  *xive;
>      sPAPRIrq *irq;
>      qemu_irq *qirqs;
>  
> diff --git a/include/hw/ppc/spapr_xive.h b/include/hw/ppc/spapr_xive.h
> index 7fdc250..556b124 100644
> --- a/include/hw/ppc/spapr_xive.h
> +++ b/include/hw/ppc/spapr_xive.h
> @@ -11,6 +11,7 @@
>  #define PPC_SPAPR_XIVE_H
>  
>  #include "hw/ppc/xive.h"
> +#include "hw/ppc/spapr.h"
>  

The sPAPRMachineState typedef statement lies in "hw/ppc/spapr_irq.h"
actually, which is a bit weird... Probably better to move the typedef
to "hw/ppc/spapr_types.h" and include it here.

>  #define TYPE_SPAPR_XIVE "spapr-xive"
>  #define SPAPR_XIVE(obj) OBJECT_CHECK(sPAPRXive, (obj), TYPE_SPAPR_XIVE)
> @@ -41,8 +42,6 @@ bool spapr_xive_irq_claim(sPAPRXive *xive, uint32_t lisn, bool lsi);
>  bool spapr_xive_irq_free(sPAPRXive *xive, uint32_t lisn);
>  void spapr_xive_pic_print_info(sPAPRXive *xive, Monitor *mon);
>  
> -typedef struct sPAPRMachineState sPAPRMachineState;
> -
>  void spapr_xive_hcall_init(sPAPRMachineState *spapr);
>  void spapr_dt_xive(sPAPRMachineState *spapr, uint32_t nr_servers, void *fdt,
>                     uint32_t phandle);
> diff --git a/target/ppc/cpu.h b/target/ppc/cpu.h
> index 486abaf..a62ff60 100644
> --- a/target/ppc/cpu.h
> +++ b/target/ppc/cpu.h
> @@ -1177,8 +1177,9 @@ do {                                            \
>  
>  typedef struct PPCVirtualHypervisor PPCVirtualHypervisor;
>  typedef struct PPCVirtualHypervisorClass PPCVirtualHypervisorClass;
> -typedef struct XiveTCTX XiveTCTX;
> -typedef struct ICPState ICPState;
> +
> +struct XiveTCTX;
> +struct ICPState;

These could be made available from the XICS/XIVE header files.

#ifndef CONFIG_USER_ONLY
#include "hw/ppc/xive.h" /* for XiveTCTX */
#include "hw/ppc/xics.h" /* for ICPState */
#endif

>  
>  /**
>   * PowerPCCPU:
> @@ -1197,8 +1198,8 @@ struct PowerPCCPU {
>      int vcpu_id;
>      uint32_t compat_pvr;
>      PPCVirtualHypervisor *vhyp;
> -    ICPState *icp;
> -    XiveTCTX *tctx;
> +    struct ICPState *icp;
> +    struct XiveTCTX *tctx;

+#ifndef CONFIG_USER_ONLY
     ICPState *icp;
     XiveTCTX *tctx;
+#endif

These aren't needed for user anyway.

>      void *machine_data;
>      int32_t node_id; /* NUMA node this CPU belongs to */
>      PPCHash64Options *hash64_opts;