On 3/23/20 2:46 PM, Daniel Brodsky wrote:
> On Mon, Mar 23, 2020 at 6:25 AM Stefan Hajnoczi <stefa...@gmail.com> wrote:
>>
>> On Fri, Mar 20, 2020 at 06:43:23AM -0700, no-re...@patchew.org wrote:
>>> /tmp/qemu-test/src/util/thread-pool.c:213:5: error: unused variable
>>> 'qemu_lockable_auto1' [-Werror,-Wunused-variable]
>>> QEMU_LOCK_GUARD(&pool->lock);
>>> ^
>>> /tmp/qemu-test/src/include/qemu/lockable.h:173:29: note: expanded from
>>> macro 'QEMU_LOCK_GUARD'
>>
>> Apparently gcc suppresses "unused variable" warnings with g_autoptr() so
>> we didn't see this warning before.
>>
>> clang does report them so let's silence the warning manually. Please
>> add G_GNUC_UNUSED onto the g_autoptr variable definition in the
>> QEMU_LOCK_GUARD() macro:
>>
>> #define QEMU_LOCK_GUARD(x) \
>> g_autoptr(QemuLockable) qemu_lockable_auto##__COUNTER__ G_GNUC_UNUSED
>> = \
>> qemu_lockable_auto_lock(QEMU_MAKE_LOCKABLE((x)))
>>
>> The WITH_*_LOCK_GUARD() macros should not require changes because the
>> variable is both read and written.
>>
>> You can test locally by building with clang (llvm) instead of gcc:
>>
>> ./configure --cc=clang
>
> Using --cc=clang is causing the following error in several different places:
> qemu/target/ppc/translate.c:1894:18: error: result of comparison
> 'target_ulong' (aka 'unsigned int') <= 4294967295
> is always true [-Werror,-Wtautological-type-limit-compare]
> if (mask <= 0xffffffffu) {
> ~~~~ ^ ~~~~~~~~~~~
>
> these errors don't come up when building with gcc. Any idea how to fix
> this? Or should I just suppress it?
I'm of the opinion that it should be suppressed.
This is the *correct* test for ppc64, and the warning for ppc32 is simply
because target_ulong == uint32_t. True is the correct result for ppc32.
We simply want the compiler to DTRT: simplify this test and remove the else as
unreachable.
r~
