| Message ID | CA+g7VZ3NkvnH7LJLP7nh2ojhXztSU--nE8GFpLTQ-B9ZsfikMw@mail.gmail.com |
|---|---|
| State | New |
| Headers | show |
On Tue, Nov 1, 2011 at 7:35 AM, Jun Koi <junkoi2004@gmail.com> wrote: > This patch explicitly initializes tcg_cpu_thread to NULL in cpus.c > (One code patch in qemu_tcg_init_vcpu() relies on the value of > tcg_cpu_thread to create env->thread and so on ) > > Signed-off-by: Jun Koi <junkoi2004@gmail.com> You don't need to explicitly initialize objects with static storage duration. They are initialized to NULL/0 implicitly. This is guaranteed by the C standard.
On Tue, Nov 1, 2011 at 3:06 PM, Pavel Borzenkov <pavel.borzenkov@gmail.com> wrote: > On Tue, Nov 1, 2011 at 7:35 AM, Jun Koi <junkoi2004@gmail.com> wrote: >> This patch explicitly initializes tcg_cpu_thread to NULL in cpus.c >> (One code patch in qemu_tcg_init_vcpu() relies on the value of >> tcg_cpu_thread to create env->thread and so on ) >> >> Signed-off-by: Jun Koi <junkoi2004@gmail.com> > > You don't need to explicitly initialize objects with static storage > duration. They are initialized to NULL/0 implicitly. > This is guaranteed by the C standard. that is good to know, but i think that is better safe than sorry. what if we compile Qemu with a compiler that doesnt follow the standard? also, i remember that we always initialize static vars? or am i wrong? thanks, Jun >> diff --git a/cpus.c b/cpus.c >> index f768683..47feb58 100644 >> --- a/cpus.c >> +++ b/cpus.c >> @@ -606,7 +606,7 @@ static bool iothread_requesting_mutex; >> >> static QemuThread io_thread; >> >> -static QemuThread *tcg_cpu_thread; >> +static QemuThread *tcg_cpu_thread = NULL; >> static QemuCond *tcg_halt_cond; >> >> /* cpu creation */ >> >> >
On Tue, Nov 1, 2011 at 12:33 PM, Jun Koi <junkoi2004@gmail.com> wrote: > On Tue, Nov 1, 2011 at 3:06 PM, Pavel Borzenkov > <pavel.borzenkov@gmail.com> wrote: >> On Tue, Nov 1, 2011 at 7:35 AM, Jun Koi <junkoi2004@gmail.com> wrote: >>> This patch explicitly initializes tcg_cpu_thread to NULL in cpus.c >>> (One code patch in qemu_tcg_init_vcpu() relies on the value of >>> tcg_cpu_thread to create env->thread and so on ) >>> >>> Signed-off-by: Jun Koi <junkoi2004@gmail.com> >> >> You don't need to explicitly initialize objects with static storage >> duration. They are initialized to NULL/0 implicitly. >> This is guaranteed by the C standard. > > that is good to know, but i think that is better safe than sorry. what > if we compile Qemu with a compiler that doesnt follow the standard? > > also, i remember that we always initialize static vars? or am i wrong? No, we don't. checkpatch.pl has a check to ensure that static variables are not explicitly initialized to NULL. Try to check your patch with this script. It will throw an error: {{{ ERROR: do not initialise statics to 0 or NULL #80: FILE: cpus.c:609: +static QemuThread *tcg_cpu_thread = NULL; total: 1 errors, 0 warnings, 8 lines checked }}}
diff --git a/cpus.c b/cpus.c index f768683..47feb58 100644 --- a/cpus.c +++ b/cpus.c @@ -606,7 +606,7 @@ static bool iothread_requesting_mutex; static QemuThread io_thread; -static QemuThread *tcg_cpu_thread; +static QemuThread *tcg_cpu_thread = NULL; static QemuCond *tcg_halt_cond; /* cpu creation */
This patch explicitly initializes tcg_cpu_thread to NULL in cpus.c (One code patch in qemu_tcg_init_vcpu() relies on the value of tcg_cpu_thread to create env->thread and so on ) Signed-off-by: Jun Koi <junkoi2004@gmail.com>