On 1/17/21 5:47 PM, Peter Maydell wrote: > On Sun, 17 Jan 2021 at 16:07, Philippe Mathieu-Daudé <f4...@amsat.org> wrote: >> >> When using GCC 10.2 configured with --extra-cflags=-Os, we get: >> >> softmmu/physmem.c: In function ‘address_space_translate_for_iotlb’: >> softmmu/physmem.c:643:26: error: ‘notifier’ may be used uninitialized in >> this function [-Werror=maybe-uninitialized] >> 643 | notifier->active = true; >> | ^ >> softmmu/physmem.c:608:23: note: ‘notifier’ was declared here >> 608 | TCGIOMMUNotifier *notifier; >> | ^~~~~~~~ >> >> Insert assertions as hint to the compiler that 'notifier' can >> not be NULL there. >> >> Signed-off-by: Philippe Mathieu-Daudé <f4...@amsat.org> >> --- >> Yet another hole in our CI. >> --- >> softmmu/physmem.c | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/softmmu/physmem.c b/softmmu/physmem.c >> index 6301f4f0a5c..65602ed548e 100644 >> --- a/softmmu/physmem.c >> +++ b/softmmu/physmem.c >> @@ -605,7 +605,7 @@ static void tcg_register_iommu_notifier(CPUState *cpu, >> * when the IOMMU tells us the mappings we've cached have changed. >> */ >> MemoryRegion *mr = MEMORY_REGION(iommu_mr); >> - TCGIOMMUNotifier *notifier; >> + TCGIOMMUNotifier *notifier = NULL; >> int i; >> >> for (i = 0; i < cpu->iommu_notifiers->len; i++) { >> @@ -638,6 +638,7 @@ static void tcg_register_iommu_notifier(CPUState *cpu, >> memory_region_register_iommu_notifier(notifier->mr, ¬ifier->n, >> &error_fatal); >> } >> + assert(notifier != NULL); >> >> if (!notifier->active) { >> notifier->active = true; > > Is the assert() necessary to prevent the compiler complaining? > Usually we don't bother if it's about to be dereferenced anyway.
Yes you are right, the assert() is not necessary. Simply initializing the value silents the error. Regards, Phil.