If -fstack-usage option is given for such architecures that do not support it, gcc displays a warning message but still exits with status 0.
This commit adds a new script to test -fstack-usage support because we cannot rely on $(call cc-option,...) .
Signed-off-by: Masahiro Yamada yamada.m@jp.panasonic.com Cc: Tom Rini trini@ti.com Cc: Michal Simek monstr@monstr.eu Cc: Jeroen Hofstee jeroen@myspectrum.nl Cc: Albert ARIBAUD albert.u.boot@aribaud.net ---
Change for v4 - Drop executable permission of scripts/gcc-stack-usage.sh - Fix commit log - Add the rationale below ---
Currently gcc does not seem to support -fstack-usage option for some targets, such as blackfin, m68k etc.
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, $(call cc-option,-fstack-usage) 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 even if -fstack-usage is unsupported.
I confirmed this like follows.
If I gave a real C file as input, the compile failed:
$ cat test.c int test(void) { return 0; } $ bfin-uclinux-gcc -fstack-usage -S -xc test.c test.c: In function 'test': test.c:4:1: warning: -fstack-usage not supported for this target [enabled by default] $ echo $? 0 $ bfin-uclinux-gcc -fstack-usage -Werror -S -xc test.c test.c: In function 'test': test.c:4:1: error: -fstack-usage not supported for this target [-Werror] cc1: all warnings being treated as errors $ echo $? 1
But I gave /dev/null as input, the compile always succeeds:
$ bfin-uclinux-gcc -fstack-usage -S -xc /dev/null $ echo $? 0 $ bfin-uclinux-gcc -Werror -fstack-usage -S -xc /dev/null $ echo $? 0
Above means we can detect -fstack-usage support by providing -Werror and -fstack-usage option for the real C source code.
But describing all of them in Makefile is not smart, I think. To keep makefile cleaner, I created a new script file 'scripts/gcc-stack-usage.sh' and pushed dirty stuff into it.
This is the way Linux Kernel often uses. For example, refer - scripts/gcc-goto.sh - scritps/gcc-version.sh etc. of Linux Kernel.
config.mk | 5 +++-- scripts/gcc-stack-usage.sh | 18 ++++++++++++++++++ 2 files changed, 21 insertions(+), 2 deletions(-) create mode 100644 scripts/gcc-stack-usage.sh
diff --git a/config.mk b/config.mk index 3441387..8a82ab4 100644 --- a/config.mk +++ b/config.mk @@ -279,8 +279,9 @@ CFLAGS_WARN := $(call cc-option,-Wno-format-nonliteral) \ CFLAGS += $(CFLAGS_WARN)
# Report stack usage if supported -CFLAGS_STACK := $(call cc-option,-fstack-usage) -CFLAGS += $(CFLAGS_STACK) +ifeq ($(shell $(SHELL) $(SRCTREE)/scripts/gcc-stack-usage.sh $(CC)), y) + CFLAGS += -fstack-usage +endif
BCURDIR = $(subst $(SRCTREE)/,,$(CURDIR:$(obj)%=%))
diff --git a/scripts/gcc-stack-usage.sh b/scripts/gcc-stack-usage.sh new file mode 100644 index 0000000..53eb10a --- /dev/null +++ b/scripts/gcc-stack-usage.sh @@ -0,0 +1,18 @@ +#!/bin/sh +# Test for gcc '-fstack-usage' support +# Copyright (C) 2013, Masahiro Yamada yamada.m@jp.panasonic.com +# +# SPDX-License-Identifier: GPL-2.0+ +# + +TMP=${OBJTREE}/"$$" + +cat << "END" | $@ -Werror -fstack-usage -x c - -c -o $TMP >/dev/null 2>&1 \ + && echo "y" +int main(void) +{ + return 0; +} +END + +rm -f $TMP $TMP.su