[Qemu-devel] [PATCH v5 2/9] make: ensure all members of libqemuutil.a are linked

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

The libqemuutil.a archive may contain QOM objects which are
only indirectly referenced via __attribute__((constructor))
annotations. Despite the constructor annotation the linker
will think these objects are unused by the executable and
so drop them when linking, to the system emulator. As a
result the objects in question will be missing from QOM.

Using the -Wl,--whole-archive flag instructs the linker
to pull in everything in libqemuutil.a regardless of
whether it thinks it is used or not.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
---
 Makefile.target | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/Makefile.target b/Makefile.target
index 3e7aafd..5b08f0f 100644
--- a/Makefile.target
+++ b/Makefile.target
@@ -180,8 +180,13 @@ all-obj-$(CONFIG_SOFTMMU) += $(block-obj-y)
 $(QEMU_PROG_BUILD): config-devices.mak
 
 # build either PROG or PROGW
+# We must use --whole-archive with libqemuutil.a otherwise the
+# linker will drop any objects from the archive which are only
+# indirectly referenced via __attribute__(constructor) annotations
 $(QEMU_PROG_BUILD): $(all-obj-y) ../libqemuutil.a ../libqemustub.a
-	$(call LINK, $(filter-out %.mak, $^))
+	$(call LINK, $(filter-out %.mak, $(sort $(all-obj-y)))) \
+		-Wl,--whole-archive ../libqemuutil.a -Wl,--no-whole-archive \
+		../libqemustub.a
 ifdef CONFIG_DARWIN
 	$(call quiet-command,Rez -append $(SRC_PATH)/pc-bios/qemu.rsrc -o $@,"  REZ   $(TARGET_DIR)$@")
 	$(call quiet-command,SetFile -a C $@,"  SETFILE $(TARGET_DIR)$@")
-- 
2.4.3