[PATCH] objtool: Skip unreachable warnings for GCC 4.4 and older

From: Josh Poimboeuf
Date: Wed Sep 27 2017 - 18:34:33 EST


The kbuild bot occasionally reports warnings like:

drivers/scsi/pcmcia/aha152x_core.o: warning: objtool: seldo_run()+0x130: unreachable instruction

These warnings are always with GCC 4.4. That version of GCC sometimes
places unreachable instructions after calls to noreturn functions.

The unreachable warnings aren't very important anyway. Just ignore them
for old versions of GCC.

Reported-by: kbuild test robot <fengguang.wu@xxxxxxxxx>
Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
---
scripts/Makefile.build | 2 ++
1 file changed, 2 insertions(+)

diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 2e3a10e79ca9..061d0c3a420a 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -265,6 +265,8 @@ objtool_args += --no-fp
endif
ifdef CONFIG_GCOV_KERNEL
objtool_args += --no-unreachable
+else
+objtool_args += $(call cc-ifversion, -lt, 0405, --no-unreachable)
endif

# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory
--
2.13.5