Re: [PATCH] or1k: Fix compilation hiccup

[Christophe de Dinechin <dinechin@redhat.com>]

On 2020-05-26 at 20:51 CEST, Eric Blake wrote...
> On my Fedora 32 machine, gcc 10.1.1 at -O2 (the default for a bare
> './configure') has a false-positive complaint:
>
>   CC      or1k-softmmu/hw/openrisc/openrisc_sim.o
> /home/eblake/qemu/hw/openrisc/openrisc_sim.c: In function ‘openrisc_sim_init’:
> /home/eblake/qemu/hw/openrisc/openrisc_sim.c:87:42: error: ‘cpu_irqs[0]’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
>    87 |         sysbus_connect_irq(s, i, cpu_irqs[i][irq_pin]);
>       |                                  ~~~~~~~~^~~
>
> Initializing both pointers of cpu_irqs[] to NULL is sufficient to shut
> up the compiler, even though they are definitely assigned in
> openrisc_sim_init() prior to the inlined call to
> openrisc_sim_ompic_init() containing the line in question.
>
> Signed-off-by: Eric Blake <eblake@redhat.com>
> ---
>  hw/openrisc/openrisc_sim.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/hw/openrisc/openrisc_sim.c b/hw/openrisc/openrisc_sim.c
> index d08ce6181199..95011a8015b4 100644
> --- a/hw/openrisc/openrisc_sim.c
> +++ b/hw/openrisc/openrisc_sim.c
> @@ -129,7 +129,7 @@ static void openrisc_sim_init(MachineState *machine)
>      const char *kernel_filename = machine->kernel_filename;
>      OpenRISCCPU *cpu = NULL;
>      MemoryRegion *ram;
> -    qemu_irq *cpu_irqs[2];
> +    qemu_irq *cpu_irqs[2] = {};

Why is the value [2] correct here? The loop that initializes loops over
machine->smp.cpus. Is it always less than 2 on this machine?


>      qemu_irq serial_irq;
>      int n;
>      unsigned int smp_cpus = machine->smp.cpus;


--
Cheers,
Christophe de Dinechin (IRC c3d)