Using __DATE__, __TIME__ would make the build non-deterministic.
If the code needs to refer to build date/time, use U_BOOT_DATE and U_BOOT_TIME in include/generated/timestamp_autogenerated.h instead.
This commit has been imported from Linux Kernel, which should be applied to U-Boot too:
commit fe7c36c7bde12190341722af69358e42171162f3 Author: Josh Triplett josh@joshtriplett.org Date: Mon Dec 23 13:56:06 2013 -0800
Makefile: Build with -Werror=date-time if the compiler supports it
GCC 4.9 and newer have a new warning -Wdate-time, which warns on any use of __DATE__, __TIME__, or __TIMESTAMP__, which would make the build non-deterministic. Now that the kernel does not use any of those macros, turn on -Werror=date-time if available, to keep it that way.
The kernel already (optionally) records this information at build time in a single place; other kernel code should not duplicate that.
Signed-off-by: Josh Triplett josh@joshtriplett.org Signed-off-by: Michal Marek mmarek@suse.cz Signed-off-by: Masahiro Yamada yamada.m@jp.panasonic.com ---
Changes in v2: - Add signed-off of the original author.
Makefile | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/Makefile b/Makefile index 0191869..09a370f 100644 --- a/Makefile +++ b/Makefile @@ -578,6 +578,9 @@ KBUILD_AFLAGS += -Wa,-gstabs,-S endif endif
+# Prohibit date/time macros, which would make the build non-deterministic +KBUILD_CFLAGS += $(call cc-option,-Werror=date-time) + ifneq ($(CONFIG_SYS_TEXT_BASE),) KBUILD_CPPFLAGS += -DCONFIG_SYS_TEXT_BASE=$(CONFIG_SYS_TEXT_BASE) endif