Re: [PATCH 2/2] hw/riscv/virt.c: fix non-KVM --enable-debug build

[Richard Henderson <richard.henderson@linaro.org>]

On 8/30/23 02:34, Daniel Henrique Barboza wrote:
> TBH I'm bothered why this doesn't work:
> 
> 
> diff --git a/hw/intc/riscv_aplic.c b/hw/intc/riscv_aplic.c
> index 592c3ce768..251e08ddc4 100644
> --- a/hw/intc/riscv_aplic.c
> +++ b/hw/intc/riscv_aplic.c
> @@ -839,12 +839,16 @@ static void riscv_aplic_realize(DeviceState *dev, Error **errp)
>        * Only root APLICs have hardware IRQ lines. All non-root APLICs
>        * have IRQ lines delegated by their parent APLIC.
>        */
> -    if (!aplic->parent) {
> -        if (is_kvm_aia(aplic->msimode)) {
> -            qdev_init_gpio_in(dev, riscv_kvm_aplic_request, aplic->num_irqs);
> -        } else {
> -            qdev_init_gpio_in(dev, riscv_aplic_request, aplic->num_irqs);
> +    if (kvm_enabled()) {
> +        if (!aplic->parent) {
> +            if (is_kvm_aia(aplic->msimode)) {
> +                qdev_init_gpio_in(dev, riscv_kvm_aplic_request, aplic->num_irqs);
> +            } else {
> +                qdev_init_gpio_in(dev, riscv_aplic_request, aplic->num_irqs);
> +            }
>           }
> +    } else if (!aplic->parent) {
> +        qdev_init_gpio_in(dev, riscv_aplic_request, aplic->num_irqs);
>       }
> 
> Why is the compiler refusing to crop an "if kvm_enabled()" block? There's no other
> conditionals to handle, and it is able to crop "if (kvm_enabled() && virt_use_kvm_aia(s))".
> 
> Is this solely because riscv_kvm_aplic_request() will be an unused function if the crop
> happens and, as you said above, "the compiler won't eliminate entire unused functions with
> -O0"?

Yes, exactly.


r~