| Message ID | 20220405112838.15360-1-shentey@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | hw/ppc/ppc405_boards: Initialize g_autofree pointer | expand |
On Tue, 5 Apr 2022 at 12:32, Bernhard Beschow <shentey@gmail.com> wrote: > > Resolves the only compiler warning when building a full QEMU under Arch Linux: > > Compiling C object libqemu-ppc-softmmu.fa.p/hw_ppc_ppc405_boards.c.o > In file included from /usr/include/glib-2.0/glib.h:114, > from qemu/include/glib-compat.h:32, > from qemu/include/qemu/osdep.h:132, > from ../src/hw/ppc/ppc405_boards.c:25: > ../src/hw/ppc/ppc405_boards.c: In function ‘ref405ep_init’: > /usr/include/glib-2.0/glib/glib-autocleanups.h:28:3: warning: ‘filename’ may be used uninitialized in this function [-Wmaybe-uninitialized] > 28 | g_free (*pp); > | ^~~~~~~~~~~~ > ../src/hw/ppc/ppc405_boards.c:265:26: note: ‘filename’ was declared here > 265 | g_autofree char *filename; > | ^~~~~~~~ > > Signed-off-by: Bernhard Beschow <shentey@gmail.com> > --- > hw/ppc/ppc405_boards.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/hw/ppc/ppc405_boards.c b/hw/ppc/ppc405_boards.c > index 7e1a4ac955..326353ea25 100644 > --- a/hw/ppc/ppc405_boards.c > +++ b/hw/ppc/ppc405_boards.c > @@ -262,7 +262,7 @@ static void ref405ep_init(MachineState *machine) > /* allocate and load BIOS */ > if (machine->firmware) { > MemoryRegion *bios = g_new(MemoryRegion, 1); > - g_autofree char *filename; > + g_autofree char *filename = NULL; > long bios_size; > > memory_region_init_rom(bios, NULL, "ef405ep.bios", BIOS_SIZE, The compiler's wrong here, because there's no way to get to the free without passing through the actual initialization: filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, machine->firmware); I think I would prefer a fix which hoisted that up to the declaration, rather than setting it to NULL and then unconditionally overwriting that (which some future compiler version might notice and warn about): g_autofree char *filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, machine->firmware); thanks -- PMM
Am 5. April 2022 12:00:19 UTC schrieb Peter Maydell <peter.maydell@linaro.org>: >On Tue, 5 Apr 2022 at 12:32, Bernhard Beschow <shentey@gmail.com> wrote: >> >> Resolves the only compiler warning when building a full QEMU under Arch Linux: >> >> Compiling C object libqemu-ppc-softmmu.fa.p/hw_ppc_ppc405_boards.c.o >> In file included from /usr/include/glib-2.0/glib.h:114, >> from qemu/include/glib-compat.h:32, >> from qemu/include/qemu/osdep.h:132, >> from ../src/hw/ppc/ppc405_boards.c:25: >> ../src/hw/ppc/ppc405_boards.c: In function ‘ref405ep_init’: >> /usr/include/glib-2.0/glib/glib-autocleanups.h:28:3: warning: ‘filename’ may be used uninitialized in this function [-Wmaybe-uninitialized] >> 28 | g_free (*pp); >> | ^~~~~~~~~~~~ >> ../src/hw/ppc/ppc405_boards.c:265:26: note: ‘filename’ was declared here >> 265 | g_autofree char *filename; >> | ^~~~~~~~ >> >> Signed-off-by: Bernhard Beschow <shentey@gmail.com> >> --- >> hw/ppc/ppc405_boards.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/hw/ppc/ppc405_boards.c b/hw/ppc/ppc405_boards.c >> index 7e1a4ac955..326353ea25 100644 >> --- a/hw/ppc/ppc405_boards.c >> +++ b/hw/ppc/ppc405_boards.c >> @@ -262,7 +262,7 @@ static void ref405ep_init(MachineState *machine) >> /* allocate and load BIOS */ >> if (machine->firmware) { >> MemoryRegion *bios = g_new(MemoryRegion, 1); >> - g_autofree char *filename; >> + g_autofree char *filename = NULL; >> long bios_size; >> >> memory_region_init_rom(bios, NULL, "ef405ep.bios", BIOS_SIZE, > >The compiler's wrong here, because there's no way to get to the free >without passing through the actual initialization: Yep. It breaks compilation with -Werror, though, which is useful for development. > > filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, machine->firmware); > >I think I would prefer a fix which hoisted that up to the declaration, >rather than setting it to NULL and then unconditionally overwriting that >(which some future compiler version might notice and warn about): > > g_autofree char *filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, >machine->firmware); Ack - I prefer that solution and I'll submit v2. I'm often confused as to when to use RAII in QEMU and when not to. Best regards, Bernhard > >thanks >-- PMM
diff --git a/hw/ppc/ppc405_boards.c b/hw/ppc/ppc405_boards.c index 7e1a4ac955..326353ea25 100644 --- a/hw/ppc/ppc405_boards.c +++ b/hw/ppc/ppc405_boards.c @@ -262,7 +262,7 @@ static void ref405ep_init(MachineState *machine) /* allocate and load BIOS */ if (machine->firmware) { MemoryRegion *bios = g_new(MemoryRegion, 1); - g_autofree char *filename; + g_autofree char *filename = NULL; long bios_size; memory_region_init_rom(bios, NULL, "ef405ep.bios", BIOS_SIZE,
Resolves the only compiler warning when building a full QEMU under Arch Linux: Compiling C object libqemu-ppc-softmmu.fa.p/hw_ppc_ppc405_boards.c.o In file included from /usr/include/glib-2.0/glib.h:114, from qemu/include/glib-compat.h:32, from qemu/include/qemu/osdep.h:132, from ../src/hw/ppc/ppc405_boards.c:25: ../src/hw/ppc/ppc405_boards.c: In function ‘ref405ep_init’: /usr/include/glib-2.0/glib/glib-autocleanups.h:28:3: warning: ‘filename’ may be used uninitialized in this function [-Wmaybe-uninitialized] 28 | g_free (*pp); | ^~~~~~~~~~~~ ../src/hw/ppc/ppc405_boards.c:265:26: note: ‘filename’ was declared here 265 | g_autofree char *filename; | ^~~~~~~~ Signed-off-by: Bernhard Beschow <shentey@gmail.com> --- hw/ppc/ppc405_boards.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)