build error of unused function as MACRO G_DEFINE_AUTOPTR_CLEANUP_FUNC expand

[Li Qiang]

Hello all,

 

I build qemu with fuzzing enabled using clang and following error come.

 

nbd/server.c:1937:1: error: unused function 'glib_listautoptr_cleanup_NBDExtentArray' [-Werror,-Wunused-function]

G_DEFINE_AUTOPTR_CLEANUP_FUNC(NBDExtentArray, nbd_extent_array_free);

^

/usr/include/glib-2.0/glib/gmacros.h:462:22: note: expanded from macro 'G_DEFINE_AUTOPTR_CLEANUP_FUNC'

  static inline void _GLIB_AUTOPTR_LIST_FUNC_NAME(TypeName) (GList **_l) { g_list_free_full (*_l, (GDestroyNotify) func); } \

                     ^

/usr/include/glib-2.0/glib/gmacros.h:443:48: note: expanded from macro '_GLIB_AUTOPTR_LIST_FUNC_NAME'

#define _GLIB_AUTOPTR_LIST_FUNC_NAME(TypeName) glib_listautoptr_cleanup_##TypeName

                                               ^

<scratch space>:170:1: note:   CC      crypto/hash-glib.o

expanded from here

glib_listautoptr_cleanup_NBDExtentArray

^

nbd/server.c:1937:1: error: unused function 'glib_slistautoptr_cleanup_NBDExtentArray' [-Werror,-Wunused-function]

/usr/include/glib-2.0/glib/gmacros.h:463:22: note: expanded from macro 'G_DEFINE_AUTOPTR_CLEANUP_FUNC'

  static inline void _GLIB_AUTOPTR_SLIST_FUNC_NAME(TypeName) (GSList **_l) { g_slist_free_full (*_l, (GDestroyNotify) func); } \

                     ^

/usr/include/glib-2.0/glib/gmacros.h:445:49: note: expanded from macro '_GLIB_AUTOPTR_SLIST_FUNC_NAME'

#define _GLIB_AUTOPTR_SLIST_FUNC_NAME(TypeName) glib_slistautoptr_cleanup_##TypeName

                                                ^

<scratch space>:171:1: note: expanded from here

glib_slistautoptr_cleanup_NBDExtentArray

 

 

I see Eric’s patch 9bda600b083(“build: Silence clang warning on older glib autoptr usage”)

So I know there should be a ‘-Wno-unused-function’ in CFLAGS. It is after ./configure:

 

CFLAGS            -g  -Wno-unused-function

QEMU_CFLAGS       -I/usr/include/pixman-1  -Werror  -pthread -I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include -fPIE -DPIE -m64 -mcx16 -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -Wstrict-prototypes -Wredundant-decls -Wall -Wundef -Wwrite-strings -Wmissing-prototypes -fno-strict-aliasing -fno-common -fwrapv -std=gnu99  -Wno-string-plus-int -Wno-typedef-redefinition -Wno-initializer-overrides -Wexpansion-to-defined -Wendif-labels -Wno-shift-negative-value -Wno-missing-include-dirs -Wempty-body -Wnested-externs -Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers -Wold-style-definition -Wtype-limits -fstack-protector-strong -I$(SRC_PATH)/capstone/include

 

However while I ‘make V=1’ I see the build nbd/serer.c using following command:

clang-8 -iquote /home/test/qemu/nbd -iquote nbd -iquote /home/test/qemu/tcg/i386 -isystem /home/test/qemu/linux-headers -isystem /home/test/qemu/linux-headers -iquote . -iquote /home/test/qemu -iquote /home/test/qemu/accel/tcg -iquote /home/test/qemu/include -iquote /home/test/qemu/disas/libvixl -I/usr/include/pixman-1  -Werror  -pthread -I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include -fPIE -DPIE -m64 -mcx16 -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -Wstrict-prototypes -Wredundant-decls -Wall -Wundef -Wwrite-strings -Wmissing-prototypes -fno-strict-aliasing -fno-common -fwrapv -std=gnu99  -Wno-string-plus-int -Wno-typedef-redefinition -Wno-initializer-overrides -Wexpansion-to-defined -Wendif-labels -Wno-shift-negative-value -Wno-missing-include-dirs -Wempty-body -Wnested-externs -Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers -Wold-style-definition -Wtype-limits -fstack-protector-strong -I/home/test/qemu/capstone/include -I/home/test/qemu/tests -I/home/test/qemu/tests/qtest -MMD -MP -MT nbd/server.o -MF nbd/server.d -fsanitize=address,fuzzer-no-link  -c -o nbd/server.o nbd/server.c

 

There’s no CFLAGS ‘-Wno-unused-function’.

 

So I want to know:

1.    Wha’t the relation of CFLAGS and QEMU_CFLAGS, it seems the CFLAGS doesn’t work in this.

2.    Any hits to solve this? My env error or needs a patch?

 

I use following command in Ubuntu 18.04.1.

CC=clang-8 CXX=clang++-8  ./configure  --target-list="i386-softmmu"  --enable-debug --enable-debug  --enable-kvm --enable-fuzzing

 

 

Thanks,

Li Qiang