uninative: Add allow-shlib-undefined to BUILD_LDFLAGS and drop other workarounds

We have a problem when for example, a glibc 2.27 based system builds some
library like libpopt-native and puts it into sstate then it is reused
on a pre glibc-2.27 system to build something which depends on popt like
rpm-native. This results in an error like:

recipe-sysroot-native/usr/lib/libpopt.so: undefined reference to `glob@GLIBC_2.27'

In the past we've had this problem with new symbols like getrandom and
getentropy, here its with a more complex symbol where there is an old
version and a newer version.

We've looked into various options, basically we cannot link against our
uninative libc/ld.so since we don't have the right headers or compiler
link libraries. The compiler doesn't allow you to switch in a new set
either, even if we did want to ship them. Shipping a complete compiler,
dev headers and libs also isn't an option.

On the other hand if we follow the ld man page, it does say:

"""
The reasons for allowing undefined symbol references in shared libraries
specified at link time are that:

- A shared library specified at link time may not be the same as the one
  that is available at load time, so the symbol might actually be
  resolvable at load time.
"""

which is exactly this case. By the time the binary runs, it will use
our uninative loader and libc and the symbol will be available.

Therefore we basically have a choice, we get weird intermittent bugs,
we drop uninative entirely, or we pass this option.

If we pass the option, we can drop the other workarounds too.

(From OE-Core rev: 75a62ede393bf6b4972390ef5290d50add19341a)

(From OE-Core rev: d18bf7fa8e80d6cfaf3fdbe1ab06eec84b954432)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/meta/classes/uninative.bbclass b/meta/classes/uninative.bbclass
index 0501ddec40..23c5314818 100644
--- a/meta/classes/uninative.bbclass
+++ b/meta/classes/uninative.bbclass
@@ -9,7 +9,7 @@ UNINATIVE_TARBALL ?= "${BUILD_ARCH}-nativesdk-libc.tar.bz2"
 UNINATIVE_DLDIR ?= "${DL_DIR}/uninative/"
 
 # Enabling uninative will change the following variables so they need to go the parsing white list to prevent multiple recipe parsing
-BB_HASHCONFIG_WHITELIST += "NATIVELSBSTRING SSTATEPOSTUNPACKFUNCS"
+BB_HASHCONFIG_WHITELIST += "NATIVELSBSTRING SSTATEPOSTUNPACKFUNCS BUILD_LDFLAGS"
 
 addhandler uninative_event_fetchloader
 uninative_event_fetchloader[eventmask] = "bb.event.BuildStarted"
@@ -129,6 +129,8 @@ def enable_uninative(d):
         d.setVar("NATIVELSBSTRING", "universal%s" % oe.utils.host_gcc_version(d))
         d.appendVar("SSTATEPOSTUNPACKFUNCS", " uninative_changeinterp")
         d.appendVarFlag("SSTATEPOSTUNPACKFUNCS", "vardepvalueexclude", "| uninative_changeinterp")
+        d.appendVar("BUILD_LDFLAGS", " -Wl,--allow-shlib-undefined")
+        d.appendVarFlag("BUILD_LDFLAGS", "vardepvalueexclude", "| -Wl,--allow-shlib-undefined")
         d.prependVar("PATH", "${STAGING_DIR}-uninative/${BUILD_ARCH}-linux${bindir_native}:")
 
 python uninative_changeinterp () {