Re: [Qemu-devel] [PATCH for-3.1 v2] build: qga: add macro to force use of native mingw32 assert()

["Daniel P. Berrangé" <berrange@redhat.com>]

On Wed, Nov 14, 2018 at 10:44:38AM -0600, Michael Roth wrote:
> When building qemu-ga for w32 with VSS support, some parts of qemu-ga
> are not linked against glib, specifically the C++ bits used to
> create the VSS provider DLL. With 3ebee3b191e, we now define assert()
> as g_assert() for all mingw32 builds via osdep.h, which results in the
> following build breakage:
> 
>   x86_64-w64-mingw32-g++ -o qga/vss-win32/qga-vss.dll qga/vss-win32/requester.o qga/vss-win32/provider.o qga/vss-win32/install.o /home/mdroth/w/qemu4.git/qga/vss-win32/qga-vss.def  -shared -Wl,--add-stdcall-alias,--enable-stdcall-fixup -lole32 -loleaut32 -lshlwapi -luuid -static
>   qga/vss-win32/requester.o: In function `requester_freeze':
>   /home/mdroth/w/qemu4.git/qga/vss-win32/requester.cpp:284: undefined reference to `g_assertion_message_expr'
>   qga/vss-win32/requester.o: In function `requester_thaw':
>   /home/mdroth/w/qemu4.git/qga/vss-win32/requester.cpp:508: undefined reference to `g_assertion_message_expr'
>   /home/mdroth/w/qemu4.git/qga/vss-win32/requester.cpp:509: undefined reference to `g_assertion_message_expr'
>   collect2: error: ld returned 1 exit status
>   make: *** [/home/mdroth/w/qemu4.git/qga/vss-win32/Makefile.objs:10: qga/vss-win32/qga-vss.dll] Error 1
>   make: *** Waiting for unfinished jobs....
> 
> Fix this by introducing a USE_NATIVE_MINGW32_ASSERT macro that can
> be defined prior to inclusion of osdep.h for build targets that
> don't link against glib.

Why doesn't it link to glib and can that be fixed ?

Glib is considered a mandatory dependancy on anything in QEMU that
uses osdep.h, since that header pulls in the glib.h header unconditionally.

> Cc: Richard Henderson <richard.henderson@linaro.org>
> Cc: Philippe Mathieu-Daudé <f4bug@amsat.org>
> Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
> ---
> v2:
>  * define USE_NATIVE_MINGW32_ASSERT via build recipe and avoid moving
>    #include's before osdep.h (Philippe)
> ---
>  include/qemu/osdep.h        | 2 +-
>  qga/vss-win32/Makefile.objs | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
> index 3bf48bcdec..59364bfeb0 100644
> --- a/include/qemu/osdep.h
> +++ b/include/qemu/osdep.h
> @@ -129,7 +129,7 @@ extern int daemon(int, int);
>   * code that is unreachable when features are disabled.
>   * All supported versions of Glib's g_assert() satisfy this requirement.
>   */
> -#ifdef __MINGW32__
> +#if defined(__MINGW32__) && !defined(USE_NATIVE_MINGW32_ASSERT)

I don't think we should have these kind of hacks.

Either make vss-win32 link to glib, or stop it importing
osdep.h entirely if it really must be built completely
standalone from normal QEMU dependancies.

>  #undef assert
>  #define assert(x)  g_assert(x)
>  #endif
> diff --git a/qga/vss-win32/Makefile.objs b/qga/vss-win32/Makefile.objs
> index 23d08da225..5773bfd868 100644
> --- a/qga/vss-win32/Makefile.objs
> +++ b/qga/vss-win32/Makefile.objs
> @@ -3,7 +3,7 @@
>  qga-vss-dll-obj-y += requester.o provider.o install.o
>  
>  obj-qga-vss-dll-obj-y = $(addprefix $(obj)/, $(qga-vss-dll-obj-y))
> -$(obj-qga-vss-dll-obj-y): QEMU_CXXFLAGS = $(filter-out -Wstrict-prototypes -Wmissing-prototypes -Wnested-externs -Wold-style-declaration -Wold-style-definition -Wredundant-decls -fstack-protector-all -fstack-protector-strong, $(QEMU_CFLAGS)) -Wno-unknown-pragmas -Wno-delete-non-virtual-dtor
> +$(obj-qga-vss-dll-obj-y): QEMU_CXXFLAGS = $(filter-out -Wstrict-prototypes -Wmissing-prototypes -Wnested-externs -Wold-style-declaration -Wold-style-definition -Wredundant-decls -fstack-protector-all -fstack-protector-strong, $(QEMU_CFLAGS)) -Wno-unknown-pragmas -Wno-delete-non-virtual-dtor -DUSE_NATIVE_MINGW32_ASSERT
>  
>  $(obj)/qga-vss.dll: LDFLAGS = -shared -Wl,--add-stdcall-alias,--enable-stdcall-fixup -lole32 -loleaut32 -lshlwapi -luuid -static
>  $(obj)/qga-vss.dll: $(obj-qga-vss-dll-obj-y) $(SRC_PATH)/$(obj)/qga-vss.def
> -- 
> 2.17.1
> 
> 

Regards,
Daniel
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