[PATCH v3] build: allow turning off --no-undefined and -z,defs
Evgeny Vereshchagin
evvers@ya.ru
Fri Dec 3 18:02:09 GMT 2021
ASan, UBSan and MSan provided by clang aren't compatible with --no-undefined and -z,defs:
https://clang.llvm.org/docs/AddressSanitizer.html#usage
https://github.com/google/sanitizers/issues/380
so to build elfutils with clang with the sanitizers it should be possible
to turn them off.
It's implemented as a standalone option because there are places like
OSS-Fuzz for example where all the sanitizer flags are passed via CFLAGS
and CXXFLAGS: https://google.github.io/oss-fuzz/getting-started/new-project-guide/#Requirements
and it should be possible to just turn off --no-undefined and -z,defs
withut flipping other "configure" options and interfering with all
those fine-grained -fsanitize=... and -fno-sanitize-recover=... compiler flags. Other than that, while
options like --enable-sanitize-undefined are helpful shortcuts, they
simply can't cover all the usecases and it's still necessary to pass
additional compiler flags to clang via CFLAGS to for example get around issues like
https://github.com/evverx/elfutils/issues/16 and
https://github.com/evverx/elfutils/issues/15.
Issues like https://bugs.llvm.org/show_bug.cgi?id=30333 have been
open since at least 2016 so it seems it's safe to say that it isn't
going to be fixed anytime soon. It's so ingrained that some build
systems complain when `-fsanitize=...` is passed to clang without
turning off no-undefined.
Without this patch something like
sed -i 's/^\(ZDEFS_LDFLAGS=\).*/\1/' configure.ac
find -name Makefile.am | xargs sed -i 's/,--no-undefined//'
should be used to make elfutils compile.
The patch was tested in https://github.com/evverx/elfutils/pull/24 by
compiling elfutils with both gcc and clang with and without ASan/UBsan
and running `make check && make distcheck`. --no-undefined and -z,defs
are still passed by default as expected.
Signed-off-by: Evgeny Vereshchagin <evvers@ya.ru>
---
ChangeLog | 5 +++++
configure.ac | 31 ++++++++++++++++++++++---------
debuginfod/Makefile.am | 2 +-
libasm/Makefile.am | 2 +-
libdw/Makefile.am | 2 +-
libelf/Makefile.am | 2 +-
6 files changed, 31 insertions(+), 13 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index d61b21c7..33d20be5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2021-12-03 Evgeny Vereshchagin <evvers@ya.ru>
+
+ * configure.ac [--disable-no-undefined]: Allow turning off
+ --no-undefined and -z,defs to build elfutils with clang sanitizers.
+
2021-11-10 Mark Wielaard <mark@klomp.org>
* configure.ac (AC_INIT): Set version to 0.186.
diff --git a/configure.ac b/configure.ac
index ff9581d2..14cd2e6f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -153,16 +153,29 @@ AC_SUBST([fpie_CFLAGS])
dso_LDFLAGS="-shared"
-ZDEFS_LDFLAGS="-Wl,-z,defs"
-AC_CACHE_CHECK([whether gcc supports $ZDEFS_LDFLAGS], ac_cv_zdefs, [dnl
-save_LDFLAGS="$LDFLAGS"
-LDFLAGS="$ZDEFS_LDFLAGS $save_LDFLAGS"
-AC_LINK_IFELSE([AC_LANG_PROGRAM()], ac_cv_zdefs=yes, ac_cv_zdefs=no)
-LDFLAGS="$save_LDFLAGS"
-])
-if test "$ac_cv_zdefs" = "yes"; then
- dso_LDFLAGS="$dso_LDFLAGS $ZDEFS_LDFLAGS"
+# ASan, UBSan and MSan provided by clang aren't compatible with --no-undefined and -z,defs:
+# https://clang.llvm.org/docs/AddressSanitizer.html#usage
+# https://github.com/google/sanitizers/issues/380
+# so to build elfutils with clang with the sanitizers it should be possible
+# to turn them off.
+AC_ARG_ENABLE([no-undefined],
+AS_HELP_STRING([--disable-no-undefined],[disable --no-undefined and -z,defs]),
+[use_no_undefined=$enableval], [use_no_undefined=yes])
+if test "$use_no_undefined" = yes; then
+ ZDEFS_LDFLAGS="-Wl,-z,defs"
+ AC_CACHE_CHECK([whether gcc supports $ZDEFS_LDFLAGS], ac_cv_zdefs, [dnl
+ save_LDFLAGS="$LDFLAGS"
+ LDFLAGS="$ZDEFS_LDFLAGS $save_LDFLAGS"
+ AC_LINK_IFELSE([AC_LANG_PROGRAM()], ac_cv_zdefs=yes, ac_cv_zdefs=no)
+ LDFLAGS="$save_LDFLAGS"
+ ])
+ if test "$ac_cv_zdefs" = "yes"; then
+ dso_LDFLAGS="$dso_LDFLAGS $ZDEFS_LDFLAGS"
+ fi
+
+ NO_UNDEFINED=",--no-undefined"
fi
+AC_SUBST([NO_UNDEFINED])
# We really want build-ids. Warn and force generating them if gcc was
# configure without --enable-linker-build-id
diff --git a/debuginfod/Makefile.am b/debuginfod/Makefile.am
index 3adb2755..58bf71d3 100644
--- a/debuginfod/Makefile.am
+++ b/debuginfod/Makefile.am
@@ -102,7 +102,7 @@ endif
$(LIBDEBUGINFOD_SONAME): $(srcdir)/libdebuginfod.map $(libdebuginfod_so_LIBS)
$(AM_V_CCLD)$(LINK) $(dso_LDFLAGS) -o $@ \
-Wl,--soname,$(LIBDEBUGINFOD_SONAME) \
- -Wl,--version-script,$<,--no-undefined \
+ -Wl,--version-script,$<$(NO_UNDEFINED) \
-Wl,--whole-archive $(libdebuginfod_so_LIBS) -Wl,--no-whole-archive \
$(libdebuginfod_so_LDLIBS)
@$(textrel_check)
diff --git a/libasm/Makefile.am b/libasm/Makefile.am
index c2b54811..683c9847 100644
--- a/libasm/Makefile.am
+++ b/libasm/Makefile.am
@@ -64,7 +64,7 @@ libasm_so_LIBS = libasm_pic.a
libasm.so: $(srcdir)/libasm.map $(libasm_so_LIBS) $(libasm_so_DEPS)
$(AM_V_CCLD)$(LINK) $(dso_LDFLAGS) -o $@ \
-Wl,--soname,$@.$(VERSION) \
- -Wl,--version-script,$<,--no-undefined \
+ -Wl,--version-script,$<$(NO_UNDEFINED) \
-Wl,--whole-archive $(libasm_so_LIBS) -Wl,--no-whole-archive \
$(libasm_so_LDLIBS)
@$(textrel_check)
diff --git a/libdw/Makefile.am b/libdw/Makefile.am
index 4fda33bd..534e5cc7 100644
--- a/libdw/Makefile.am
+++ b/libdw/Makefile.am
@@ -114,7 +114,7 @@ libdw_so_LDLIBS = $(libdw_so_DEPS) -ldl -lz $(argp_LDADD) $(fts_LIBS) $(obstack_
libdw.so: $(srcdir)/libdw.map $(libdw_so_LIBS) $(libdw_so_DEPS)
$(AM_V_CCLD)$(LINK) $(dso_LDFLAGS) -o $@ \
-Wl,--soname,$@.$(VERSION),--enable-new-dtags \
- -Wl,--version-script,$<,--no-undefined \
+ -Wl,--version-script,$<$(NO_UNDEFINED) \
-Wl,--whole-archive $(libdw_so_LIBS) -Wl,--no-whole-archive \
$(libdw_so_LDLIBS)
@$(textrel_check)
diff --git a/libelf/Makefile.am b/libelf/Makefile.am
index 560ed45f..034b7a0d 100644
--- a/libelf/Makefile.am
+++ b/libelf/Makefile.am
@@ -115,7 +115,7 @@ libelf_so_LIBS = libelf_pic.a
libelf.so: $(srcdir)/libelf.map $(libelf_so_LIBS) $(libelf_so_DEPS)
$(AM_V_CCLD)$(LINK) $(dso_LDFLAGS) -o $@ \
-Wl,--soname,$@.$(VERSION) \
- -Wl,--version-script,$<,--no-undefined \
+ -Wl,--version-script,$<$(NO_UNDEFINED) \
-Wl,--whole-archive $(libelf_so_LIBS) -Wl,--no-whole-archive \
$(libelf_so_LDLIBS)
@$(textrel_check)
--
2.31.1
More information about the Elfutils-devel
mailing list