Re: [PATCH v2] hw/i386: changes towards enabling -Wshadow=local

["Michael S. Tsirkin" <mst@redhat.com>]

On Thu, Sep 28, 2023 at 09:14:07AM +0530, Ani Sinha wrote:
> 
> 
> > On 27-Sep-2023, at 8:55 PM, Michael S. Tsirkin <mst@redhat.com> wrote:
> > 
> > On Tue, Sep 26, 2023 at 11:22:35AM +0530, Ani Sinha wrote:
> >> Code changes that addresses all compiler complaints coming from enabling
> >> -Wshadow flags. Enabling -Wshadow catches cases of local variables shadowing
> >> other local variables or parameters. These makes the code confusing and/or adds
> > 
> > These make
> > 
> >> bugs that are difficult to catch.
> >> 
> >> CC: Markus Armbruster <armbru@redhat.com>
> >> CC: Philippe Mathieu-Daude <philmd@linaro.org>
> >> CC: mst@redhat.com
> >> Message-Id: <87r0mqlf9x.fsf@pond.sub.org>
> >> Signed-off-by: Ani Sinha <anisinha@redhat.com>
> >> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
> >> Reviewed-by: Peter Xu <peterx@redhat.com>
> >> ---
> > 
> > 
> > chunks seem unrelated. why not split them up?
> 
> ? No idea what you talking about. Here and ...

you patch 4 files in a single patch.
intel_iommu is part of vtd emulation and
has separate maintainers. Slightly better to split up
to have each maintainer get just the patches
he cares about.
Not critical, for sure.


> > 
> >> hw/i386/acpi-microvm.c | 12 ++++++------
> >> hw/i386/intel_iommu.c  |  8 ++++----
> >> hw/i386/pc.c           |  1 -
> >> hw/i386/x86.c          |  2 --
> >> 4 files changed, 10 insertions(+), 13 deletions(-)
> >> 
> >> changelog:
> >> v2: kept Peter's changes from https://lore.kernel.org/r/20230922160410.138786-1-peterx@redhat.com
> >> and removed mine.
> >> 
> >> diff --git a/hw/i386/acpi-microvm.c b/hw/i386/acpi-microvm.c
> >> index a075360d85..6e4f8061eb 100644
> >> --- a/hw/i386/acpi-microvm.c
> >> +++ b/hw/i386/acpi-microvm.c
> >> @@ -78,18 +78,18 @@ static void acpi_dsdt_add_virtio(Aml *scope,
> >>             hwaddr base = VIRTIO_MMIO_BASE + index * 512;
> >>             hwaddr size = 512;
> >> 
> >> -            Aml *dev = aml_device("VR%02u", (unsigned)index);
> >> -            aml_append(dev, aml_name_decl("_HID", aml_string("LNRO0005")));
> >> -            aml_append(dev, aml_name_decl("_UID", aml_int(index)));
> >> -            aml_append(dev, aml_name_decl("_CCA", aml_int(1)));
> >> +            Aml *adev = aml_device("VR%02u", (unsigned)index);
> >> +            aml_append(adev, aml_name_decl("_HID", aml_string("LNRO0005")));
> >> +            aml_append(adev, aml_name_decl("_UID", aml_int(index)));
> >> +            aml_append(adev, aml_name_decl("_CCA", aml_int(1)));
> >> 
> >>             Aml *crs = aml_resource_template();
> >>             aml_append(crs, aml_memory32_fixed(base, size, AML_READ_WRITE));
> >>             aml_append(crs,
> >>                        aml_interrupt(AML_CONSUMER, AML_LEVEL, AML_ACTIVE_HIGH,
> >>                                      AML_EXCLUSIVE, &irq, 1));
> >> -            aml_append(dev, aml_name_decl("_CRS", crs));
> >> -            aml_append(scope, dev);
> >> +            aml_append(adev, aml_name_decl("_CRS", crs));
> >> +            aml_append(scope, adev);
> >>         }
> >>     }
> >> }
> > 
> > I would prefer to just drop the devicestate dev pointer, use kid->child inside the
> > macro.
> 
> Here …
> 

Well, you renamed dev to adev because there's another dev at
an outer scope which is set to kid->child, and only used
once. I suggest just dropping that one instead of removing
this one.


> > 
> >> diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
> >> index c0ce896668..2c832ab68b 100644
> >> --- a/hw/i386/intel_iommu.c
> >> +++ b/hw/i386/intel_iommu.c
> >> @@ -3744,7 +3744,7 @@ VTDAddressSpace *vtd_find_add_as(IntelIOMMUState *s, PCIBus *bus,
> >> /* Unmap the whole range in the notifier's scope. */
> >> static void vtd_address_space_unmap(VTDAddressSpace *as, IOMMUNotifier *n)
> >> {
> >> -    hwaddr size, remain;
> >> +    hwaddr total, remain;
> >>     hwaddr start = n->start;
> >>     hwaddr end = n->end;
> >>     IntelIOMMUState *s = as->iommu_state;
> >> @@ -3765,7 +3765,7 @@ static void vtd_address_space_unmap(VTDAddressSpace *as, IOMMUNotifier *n)
> >>     }
> >> 
> >>     assert(start <= end);
> >> -    size = remain = end - start + 1;
> >> +    total = remain = end - start + 1;
> >> 
> >>     while (remain >= VTD_PAGE_SIZE) {
> >>         IOMMUTLBEvent event;
> >> @@ -3793,10 +3793,10 @@ static void vtd_address_space_unmap(VTDAddressSpace *as, IOMMUNotifier *n)
> >>     trace_vtd_as_unmap_whole(pci_bus_num(as->bus),
> >>                              VTD_PCI_SLOT(as->devfn),
> >>                              VTD_PCI_FUNC(as->devfn),
> >> -                             n->start, size);
> >> +                             n->start, total);
> >> 
> >>     map.iova = n->start;
> >> -    map.size = size - 1; /* Inclusive */
> >> +    map.size = total - 1; /* Inclusive */
> >>     iova_tree_remove(as->iova_tree, map);
> >> }
> >> 
> > 
> > 
> > arguably an improvement
> > 
> > 
> >> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> >> index 3db0743f31..e7a233e886 100644
> >> --- a/hw/i386/pc.c
> >> +++ b/hw/i386/pc.c
> >> @@ -1116,7 +1116,6 @@ void pc_memory_init(PCMachineState *pcms,
> >> 
> >>     if (machine->device_memory) {
> >>         uint64_t *val = g_malloc(sizeof(*val));
> >> -        PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(pcms);
> >>         uint64_t res_mem_end = machine->device_memory->base;
> >> 
> >>         if (!pcmc->broken_reserved_end) {
> >> diff --git a/hw/i386/x86.c b/hw/i386/x86.c
> >> index f034df8bf6..b3d054889b 100644
> >> --- a/hw/i386/x86.c
> >> +++ b/hw/i386/x86.c
> >> @@ -365,8 +365,6 @@ void x86_cpu_pre_plug(HotplugHandler *hotplug_dev,
> >> 
> >>     cpu_slot = x86_find_cpu_slot(MACHINE(x86ms), cpu->apic_id, &idx);
> >>     if (!cpu_slot) {
> >> -        MachineState *ms = MACHINE(x86ms);
> >> -
> >>         x86_topo_ids_from_apicid(cpu->apic_id, &topo_info, &topo_ids);
> >>         error_setg(errp,
> >>             "Invalid CPU [socket: %u, die: %u, core: %u, thread: %u] with"
> > 
> > 
> > killing dead code, nice
> > 
> >> -- 
> >> 2.39.3