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office-gobmx/external/libqxp/ax_gcc_func_attribute.m4.patch

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Fix use of -fvisibility=hidden with Clang in external/libcdr, external/libqxp At least on macOS x86-64 you get a warning > [build LNK] Library/libwpftdrawlo.dylib > ld: warning: direct access in function 'std::__1::__shared_ptr_pointer<librevenge::RVNGInputStream*, std::__1::shared_ptr<librevenge::RVNGInputStream>::__shared_ptr_default_delete<librevenge::RVNGInputStream, librevenge::RVNGInputStream>, std::__1::allocator<librevenge::RVNGInputStream> >::__get_deleter(std::type_info const&) const' from file 'workdir/UnpackedTarball/libzmf/src/lib/.libs/libzmf-0.0.a(ZMFDocument.o)' to global weak symbol 'typeinfo for std::__1::shared_ptr<librevenge::RVNGInputStream>::__shared_ptr_default_delete<librevenge::RVNGInputStream, librevenge::RVNGInputStream>' from file 'workdir/UnpackedTarball/libcdr/src/lib/.libs/libcdr-0.1.a(CDRDocument.o)' means the weak symbol cannot be overridden at runtime. This was likely caused by different translation units being compiled with different visibility settings. The reason is that libzmf uses -fvisibility=hidden and generates > $ nm -m workdir/UnpackedTarball/libzmf/src/lib/.libs/libzmf-0.0.a | grep __ZTINSt3__110shared_ptrIN10librevenge15RVNGInputStreamEE27__shared_ptr_default_deleteIS2_S2_EE > 0000000000006dd8 (__DATA,__const) weak private external __ZTINSt3__110shared_ptrIN10librevenge15RVNGInputStreamEE27__shared_ptr_default_deleteIS2_S2_EE while libcdr erroneously does not use -fvisibility=hidden and generates > $ nm -m workdir/UnpackedTarball/libcdr/src/lib/.libs/libcdr-0.1.a | grep __ZTINSt3__110shared_ptrIN10librevenge15RVNGInputStreamEE27__shared_ptr_default_deleteIS2_S2_EE > 00000000000072b8 (__DATA,__const) weak external __ZTINSt3__110shared_ptrIN10librevenge15RVNGInputStreamEE27__shared_ptr_default_deleteIS2_S2_EE The reason for that error is as follows: workdir/UnpackedTarball/libcdr/configure.ac uses, among other things, the result of AX_GCC_FUNC_ATTRIBUTE([visibility]) when deciding whether to use -fvisibility=hidden. And the old ("serial 5") workdir/UnpackedTarball/libcdr/m4/ax_gcc_func_attribute.m4 decides "no" if its test compilation generates any warning output. But Clang on macOS generates > conftest.cpp:34:56: warning: target does not support 'protected' visibility; using 'default' [-Wunsupported-visibility] > int foo_pro( void ) __attribute__((visibility("protected"))); > ^ and lots of > conftest.cpp:2:9: warning: macro is not used [-Wunused-macros] > #define PACKAGE_NAME "libcdr" > ^ (because of -Wunused-macros set for Clang in solenv/gbuild/platform/com_GCC_defs.mk). Same issue with external/libqxp, which would cause > [LNK] Library/libwpftdrawlo.dylib > ld: warning: direct access in function 'std::__1::__shared_ptr_pointer<librevenge::RVNGInputStream*, std::__1::shared_ptr<librevenge::RVNGInputStream>::__shared_ptr_default_delete<librevenge::RVNGInputStream, librevenge::RVNGInputStream>, std::__1::allocator<librevenge::RVNGInputStream> >::__get_deleter(std::type_info const&) const' from file 'workdir/UnpackedTarball/libcdr/src/lib/.libs/libcdr-0.1.a(CDRDocument.o)' to global weak symbol 'typeinfo for std::__1::shared_ptr<librevenge::RVNGInputStream>::__shared_ptr_default_delete<librevenge::RVNGInputStream, librevenge::RVNGInputStream>' from file 'workdir/UnpackedTarball/libqxp/src/lib/.libs/libqxp-0.0.a(QXPMacFileParser.o)' means the weak symbol cannot be overridden at runtime. This was likely caused by different translation units being compiled with different visibility settings. <http://git.savannah.gnu.org/gitweb/?p=autoconf-archive.git;a=commitdiff; h=df0894ad1a8195df67a52108b931e07d708cec9a> "ax_gcc_func_attribute: Revise the detection of unknown attributes", even though it was apparently meant to fix something different, nicely fixes this Clang issue, making AX_GCC_FUNC_ATTRIBUTE correctly detect support for visibility now. When building with Clang on Linux, there is no -Wunsupported-visibility about __attribute__((visibility("protected"))), but all the -Wunused-macros are present as well, which caused all the AX_GCC_FUNC_ATTRIBUTE checks to be mis- detected as "no" there, too. There are more uses of AX_GCC_FUNC_ATTRIBUTE in workdir/UnpackedTarball/libcdr/configure.ac and workdir/UnpackedTarball/libqxp/configure.ac, and there are many more workdir/UnpackedTarball/*/m4/ax_gcc_func_attribute.m4 in other external projects, all of which may cause similar AX_GCC_FUNC_ATTRIBUTE mis-detections. However, they do not cause any noticeable traces like the "direct access" ld warning here, so I left those alone for now. (Ultimately, all the upstream external projects should probably deploy the latest version of ax_gcc_func_attribute.m4 from <http://git.savannah.gnu.org/gitweb/?p=autoconf-archive.git;a=blob_plain; f=m4/ax_gcc_func_attribute.m4>.) Change-Id: Ia0560cace770ec7da9ee390566a01a5c592f9209 Reviewed-on: https://gerrit.libreoffice.org/c/core/+/109774 Tested-by: Stephan Bergmann <sbergman@redhat.com> Reviewed-by: Stephan Bergmann <sbergman@redhat.com>
2021-01-21 16:19:20 -06:00
--- configure
+++ configure
@@ -18136,7 +18136,7 @@
_ACEOF
if ac_fn_cxx_try_link "$LINENO"; then :
- if test -s conftest.err; then :
+ if grep -- -Wattributes conftest.err; then :
ax_cv_have_func_attribute_visibility=no
else
ax_cv_have_func_attribute_visibility=yes
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