Clang 13.0.0 produces a new -Werror warning about the ACPI_TO_INTEGER(p)
and ACPI_OFFSET(d, f) macros in acpica's actypes.h:
sys/contrib/dev/acpica/components/dispatcher/dsopcode.c:708:31: error: performing pointer subtraction with a null pointer has undefined behavior [-Werror,-Wnull-pointer-subtraction] ObjDesc->Region.Address = ACPI_PTR_TO_PHYSADDR (Table); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ sys/contrib/dev/acpica/include/actypes.h:664:41: note: expanded from macro 'ACPI_PTR_TO_PHYSADDR' #define ACPI_PTR_TO_PHYSADDR(i) ACPI_TO_INTEGER(i) ^~~~~~~~~~~~~~~~~~ sys/contrib/dev/acpica/include/actypes.h:661:41: note: expanded from macro 'ACPI_TO_INTEGER' #define ACPI_TO_INTEGER(p) ACPI_PTR_DIFF (p, (void *) 0) ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ sys/contrib/dev/acpica/include/actypes.h:656:82: note: expanded from macro 'ACPI_PTR_DIFF' #define ACPI_PTR_DIFF(a, b) ((ACPI_SIZE) (ACPI_CAST_PTR (UINT8, (a)) - ACPI_CAST_PTR (UINT8, (b)))) ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~ 1 error generated.
Instead fix these locally, for ACPI_TO_INTEGER by simply casting the
incoming pointer to ACPI_SIZE (which corresponds roughly to uintptr_t
and size_t), and for ACPI_OFFSET by reusing our offsetof definition from
I didn't want to use our offsetof() or builtin_offsetof(), as this
might not be acceptable for upstream. But if upstream is not going to
accept this patch anyway, we might as well just use or own macros.