Hi Masahiro,
On Tue, 15 Oct 2013 17:24:17 +0900, Masahiro Yamada yamada.m@jp.panasonic.com wrote:
Currently gcc does not seem to support -fstack-usage option for some targets, such as blackfin and m68k.
If -fstack-usage option is given for those targets, gcc displays a warning message as follows:
warning: -fstack-usage not supported for this target [enabled by default]But it still exits with status 0.
So,
# Report stack usage if supported CFLAGS_STACK := $(call cc-option,-fstack-usage) CFLAGS += $(CFLAGS_STACK)does not work as we expect because cc-option sees exit status to judge whether the given option is supported or not.
Adding -Werror option to cc-option function does not work either, because gcc always succeeds in compiling /dev/null input with -fstack-usage option. We cannot rely on cc-option.
To suppress warnings for such targets that -fstack-usage is not supported, this commit surrounds the concerned lines with ifdef CONFIG_CC_STACKUSAGE .. endif. And it adds CONFIG_CC_STACKUSAGE=y to arch/${ARCH}/config.mk except blackfin and m68k.
Please keep the commit message to a (short) description of the patch, and move the rationale to a comment below the '---' line.
Also: what is the benefit of creating an elaborate mechanism to hide a warning message that says the option is useless, IOW, wouldn't it be simpler to only specify -fstack-usage to the arches that support it?
Amicalement,