From 93c690eba8ca67b06925d811ea87765215401385 Mon Sep 17 00:00:00 2001
From: Justin Chadwell <justin.chadwell@arm.com>
Date: Wed, 3 Jul 2019 14:15:56 +0100
Subject: [PATCH] Enable -Wshift-overflow=2 to check for undefined shift
behavior
The -Wshift-overflow=2 option enables checks for left bit shifts.
Specifically, the option will warn when the result of a shift will be
placed into a signed integer and overflow the sign bit there, which
results in undefined behavior.
To avoid the warnings from these checks, the left operand of a shift can
be made an unsigned integer by using the U() macro or appending the u
suffix.
Change-Id: I50c67bedab86a9fdb6c87cfdc3e784f01a22d560
Signed-off-by: Justin Chadwell <justin.chadwell@arm.com>
---
Makefile | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/Makefile b/Makefile
index 471cf5982..c47309293 100644
--- a/Makefile
+++ b/Makefile
@@ -256,9 +256,14 @@ WARNINGS += -Wunused -Wno-unused-parameter \
-Wvla
ifeq ($(findstring clang,$(notdir $(CC))),)
+# not using clang
WARNINGS += -Wunused-but-set-variable \
-Wmaybe-uninitialized \
- -Wpacked-bitfield-compat
+ -Wpacked-bitfield-compat \
+ -Wshift-overflow=2
+else
+# using clang
+WARNINGS += -Wshift-overflow -Wshift-sign-overflow
endif
ifneq (${E},0)
--
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