On Mon, Nov 28, 2016 at 11:57 AM, Laszlo Ersek <ler...@redhat.com> wrote:
> According to ISO C99 / N1256 (referenced in HACKING):
>
>> 6.5.8 Relational operators
>>
>> 4 For the purposes of these operators, a pointer to an object that is
>> not an element of an array behaves the same as a pointer to the first
>> element of an array of length one with the type of the object as its
>> element type.
>>
>> 5 When two pointers are compared, the result depends on the relative
>> locations in the address space of the objects pointed to. If two
>> pointers to object or incomplete types both point to the same object,
>> or both point one past the last element of the same array object, they
>> compare equal. If the objects pointed to are members of the same
>> aggregate object, pointers to structure members declared later compare
>> greater than pointers to members declared earlier in the structure,
>> and pointers to array elements with larger subscript values compare
>> greater than pointers to elements of the same array with lower
>> subscript values. All pointers to members of the same union object
>> compare equal. If the expression /P/ points to an element of an array
>> object and the expression /Q/ points to the last element of the same
>> array object, the pointer expression /Q+1/ compares greater than /P/.
>> In all other cases, the behavior is undefined.
>
> Our AddressSpace objects are allocated generally individually, and kept in
> the "address_spaces" linked list, so we mustn't compare their addresses
> with relops.
>
> Convert the pointers subjected to the relop in rom_order_compare() to
> "uintptr_t":
>
>> 7.18.1.4 Integer types capable of holding object pointers
>>
>> 1 [...]
>>
>> The following type designates an unsigned integer type with the
>> property that any valid pointer to void can be converted to this type,
>> then converted back to pointer to void, and the result will compare
>> equal to the original pointer:
>>
>> /uintptr_t/
>>
>> These types are optional.
>
> Cc: "Michael S. Tsirkin" <m...@redhat.com>
> Cc: Alistair Francis <alistair.fran...@xilinx.com>
> Cc: Paolo Bonzini <pbonz...@redhat.com>
> Cc: Peter Maydell <peter.mayd...@linaro.org>
> Cc: qemu-devel@nongnu.org
> Fixes: 3e76099aacb4dae0d37ebf95305369e03d1491e6
> Signed-off-by: Laszlo Ersek <ler...@redhat.com>
Reviewed-by: Alistair Francis <alistair.fran...@xilinx.com>
Thanks,
Alistair
> ---
> hw/core/loader.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/hw/core/loader.c b/hw/core/loader.c
> index c0d645a87134..766e48f2aec2 100644
> --- a/hw/core/loader.c
> +++ b/hw/core/loader.c
> @@ -818,7 +818,7 @@ static QTAILQ_HEAD(, Rom) roms =
> QTAILQ_HEAD_INITIALIZER(roms);
>
> static inline bool rom_order_compare(Rom *rom, Rom *item)
> {
> - return (rom->as > item->as) ||
> + return ((uintptr_t)(void*)rom->as > (uintptr_t)(void*)item->as) ||
> (rom->as == item->as && rom->addr >= item->addr);
> }
>
> --
> 2.9.2
>
>
