[libvirt] [PATCH 06/15] Generate libvirt.def from libvirt.syms

Daniel P. Berrange berrange at redhat.com
Wed Apr 7 13:00:47 UTC 2010


On Mon, Mar 22, 2010 at 02:25:36AM +0100, Matthias Bolte wrote:
> The MinGW linker needs the libvirt.def file.
> ---
>  configure.ac    |    5 +++++
>  src/.gitignore  |    1 +
>  src/Makefile.am |   15 +++++++++++----
>  3 files changed, 17 insertions(+), 4 deletions(-)
> 
> diff --git a/configure.ac b/configure.ac
> index bcf1d5a..6e568ee 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -1733,6 +1733,7 @@ CYGWIN_EXTRA_LIBADD=
>  CYGWIN_EXTRA_PYTHON_LIBADD=
>  MINGW_EXTRA_LDFLAGS=
>  WIN32_EXTRA_CFLAGS=
> +LIBVIRT_SYMBOL_FILE=libvirt.syms
>  case "$host" in
>    *-*-cygwin*)
>      CYGWIN_EXTRA_LDFLAGS="-no-undefined"
> @@ -1752,6 +1753,9 @@ case "$host" in
>      if test "x$enable_shared" = "xno"; then
>        WIN32_EXTRA_CFLAGS="-DLIBVIRT_STATIC"
>      fi
> +    # Also set the symbol file to .def, so src/Makefile generates libvirt.def
> +    # from libvirt.syms and passes libvirt.def instead of libvirt.syms to the linker
> +    LIBVIRT_SYMBOL_FILE=libvirt.def
>      ;;
>  esac
>  AC_SUBST([CYGWIN_EXTRA_LDFLAGS])
> @@ -1759,6 +1763,7 @@ AC_SUBST([CYGWIN_EXTRA_LIBADD])
>  AC_SUBST([CYGWIN_EXTRA_PYTHON_LIBADD])
>  AC_SUBST([MINGW_EXTRA_LDFLAGS])
>  AC_SUBST([WIN32_EXTRA_CFLAGS])
> +AC_SUBST([LIBVIRT_SYMBOL_FILE])
>  
>  dnl Look for windres to build a Windows icon resource.
>  AC_CHECK_TOOL([WINDRES], [windres], [no])
> diff --git a/src/.gitignore b/src/.gitignore
> index 26b8689..a5c27a5 100644
> --- a/src/.gitignore
> +++ b/src/.gitignore
> @@ -12,6 +12,7 @@ Makefile.in
>  *.cov
>  libvirt_parthelper
>  libvirt_lxc
> +libvirt.def
>  libvirt.syms
>  *.i
>  *.s
> diff --git a/src/Makefile.am b/src/Makefile.am
> index 0aa3443..fea1bd3 100644
> --- a/src/Makefile.am
> +++ b/src/Makefile.am
> @@ -828,7 +828,7 @@ EXTRA_DIST += \
>    libvirt_macvtap.syms		\
>    libvirt_daemon.syms
>  
> -BUILT_SOURCES = libvirt.syms
> +BUILT_SOURCES = libvirt.syms libvirt.def
>  
>  libvirt.syms: libvirt_public.syms $(USED_SYM_FILES)
>  	rm -f $@-tmp $@
> @@ -844,18 +844,25 @@ libvirt.syms: libvirt_public.syms $(USED_SYM_FILES)
>  	chmod a-w $@-tmp
>  	mv $@-tmp libvirt.syms
>  
> +libvirt.def: libvirt.syms
> +	rm -f -- $@-tmp $@
> +	printf 'EXPORTS\n' > $@-tmp
> +	sed -e '/^$$/d; /#/d; /:/d; /\}/d; /\*/d; /LIBVIRT_/d; s/\(.*\)\;/\1/g' $^ >> $@-tmp
> +	chmod a-w $@-tmp
> +	mv $@-tmp libvirt.def
> +
>  # Empty source list - it merely links a bunch of convenience libs together
>  libvirt_la_SOURCES =
>  libvirt_la_LIBADD += \
>  		    $(CYGWIN_EXTRA_LIBADD) ../gnulib/lib/libgnu.la
> -libvirt_la_LDFLAGS = $(VERSION_SCRIPT_FLAGS)libvirt.syms \
> +libvirt_la_LDFLAGS = $(VERSION_SCRIPT_FLAGS)$(LIBVIRT_SYMBOL_FILE) \
>                       -version-info $(LIBVIRT_VERSION_INFO) \
>                      $(COVERAGE_CFLAGS:-f%=-Wc,-f%) \
>                      $(LIBXML_LIBS) \
>  		    $(DRIVER_MODULE_LIBS) \
>  		    $(CYGWIN_EXTRA_LDFLAGS) $(MINGW_EXTRA_LDFLAGS)
>  libvirt_la_CFLAGS = $(COVERAGE_CFLAGS) -DIN_LIBVIRT
> -libvirt_la_DEPENDENCIES = $(libvirt_la_LIBADD) libvirt.syms
> +libvirt_la_DEPENDENCIES = $(libvirt_la_LIBADD) $(LIBVIRT_SYMBOL_FILE)
>  
>  # Create an automake "convenience library" version of libvirt_la,
>  # just for testing, since the test harness requires access to internal
> @@ -865,7 +872,7 @@ noinst_LTLIBRARIES += libvirt_test.la
>  # Remove version script from convenience library
>  test_LDFLAGS =						\
>    $$(echo '$(libvirt_la_LDFLAGS)'			\
> -     |sed 's!$(VERSION_SCRIPT_FLAGS)libvirt.syms!!'	\
> +     |sed 's!$(VERSION_SCRIPT_FLAGS)$(LIBVIRT_SYMBOL_FILE)!!'	\
>       |sed 's!-version-info $(LIBVIRT_VERSION_INFO)!!')
>  
>  # Just like the above, but with a slightly different set of public symbols.

I've re-examined this now to discover why we had this regression.

Originally, say in 0.7.5, everything was linking fine on Mingw32 without
this .defs file.  I figured out that this is because Mingw32 was ignoring
our .syms file, and using its default logic of exporting *everything* :-)

Then, in

commit 190aaa2627a8c6e455088f1e7801708fb5f123b1
Author: Matthias Bolte <matthias.bolte at googlemail.com>
Date:   Tue Mar 16 23:54:22 2010 +0100

    Fix export of virConnectAuthPtrDefault for MinGW builds
    
    Use the __declspec(dllexport/dllimport) stuff to export the symbol,
    otherwise accessing virConnectAuthPtrDefault triggers a segfault.


We used declspec() on the virConnectAuthPtrDefault. This turned off the
Mingw32 logic that exported everything & thus caused virsh link failures.

Adding this .defs file as per your patch re-exports everything.

It sucks that we export everything, but it is no worse than the old
situation we had on mingw.

ACK to this patch

Daniel
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