Message ID | 5245C703.6060907@myspectrum.nl |
---|---|
State | Not Applicable |
Headers | show |
Hello Jeroen, > diff --git a/config.mk b/config.mk > index 48913f6..177f685 100644 > --- a/config.mk > +++ b/config.mk > @@ -117,7 +117,7 @@ CC_TEST_OFILE := > $(OBJTREE)/include/generated/cc_test_file.o > -include $(CC_OPTIONS_CACHE_FILE) > > cc-option-sys = $(shell mkdir -p $(dir $(CC_TEST_OFILE)); \ > - if $(CC) $(CFLAGS) $(1) -S -xc /dev/null -o > $(CC_TEST_OFILE) \ > + if $(CC) -Werror $(CFLAGS) $(1) -S -xc /dev/null -o > $(CC_TEST_OFILE) \ > > /dev/null 2>&1; then \ > echo 'CC_OPTIONS += $(strip $1)' >> > $(CC_OPTIONS_CACHE_FILE); \ > echo "$(1)"; fi) It looks like this was already suggested by Tom too. See http://patchwork.ozlabs.org/patch/183174/ I tested this patch but unfortunatelly it did not work. I downloaded bfin-linux-gcc 4.6.3 from ftp://ftp.kernel.org/pub/tools/crosstool/index.html I added -Werror to config.mk and I tried: CROSS_COMPILE=bfin-linux- ./MAKEALL -a blackfin The log message was still sprinkled with lots of warnings like warning: -fstack-usage not supported for this target [enabled by default] So, I looked into it more closely and I found gcc can compile the input file /dev/null successfully even if -fstack-usage is not supported. $ bfin-uclinux-gcc -fstack-usage -S -xc /dev/null $ echo $? 0 $ bfin-uclinux-gcc -Werror -fstack-usage -S -xc /dev/null $ echo $? 0 Instead of /dev/null, I prepared a very simple C source code as an input. $ 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 This time we can detect unsupported -fstack-usage by the exit status. So, along with -Werror, I think /dev/null should also be replaced with some _REAL_ C source file. But my concern about this treak is we might go far from Kbuild. In Linux Kernel, cc-option is impilemented in scripts/Kbuild.include. It uses /dev/null as input. I wish U-Boot would someday adopt (not nessarily the same but very similar) Kbuild. If you see Linux Kernel top Makefile, many of optional CFLAGS are provided thru cc-option and also can be turned on/off by CONFIG_ switch. That is one reason I suggested to introduce CONFIG_CC_STACKUSAGE option. But this is just my opinion and I would not necessarily stick to this idea. Please feel free to suggest your thought. Best Regards Masahiro Yamada
Hello Masahiro, On 09/30/2013 10:01 AM, Masahiro Yamada wrote: > Hello Jeroen, > >> diff --git a/config.mk b/config.mk >> index 48913f6..177f685 100644 >> --- a/config.mk >> +++ b/config.mk >> @@ -117,7 +117,7 @@ CC_TEST_OFILE := >> $(OBJTREE)/include/generated/cc_test_file.o >> -include $(CC_OPTIONS_CACHE_FILE) >> >> cc-option-sys = $(shell mkdir -p $(dir $(CC_TEST_OFILE)); \ >> - if $(CC) $(CFLAGS) $(1) -S -xc /dev/null -o >> $(CC_TEST_OFILE) \ >> + if $(CC) -Werror $(CFLAGS) $(1) -S -xc /dev/null -o >> $(CC_TEST_OFILE) \ >> > /dev/null 2>&1; then \ >> echo 'CC_OPTIONS += $(strip $1)' >> >> $(CC_OPTIONS_CACHE_FILE); \ >> echo "$(1)"; fi) > > > It looks like this was already suggested by Tom too. > See http://patchwork.ozlabs.org/patch/183174/ > > I tested this patch but unfortunatelly it did not work. > > > I downloaded bfin-linux-gcc 4.6.3 from > ftp://ftp.kernel.org/pub/tools/crosstool/index.html > > I added -Werror to config.mk and I tried: > > CROSS_COMPILE=bfin-linux- ./MAKEALL -a blackfin > > The log message was still sprinkled with lots of warnings like > warning: -fstack-usage not supported for this target [enabled by default] > > So, I looked into it more closely and > I found gcc can compile the input file /dev/null successfully > even if -fstack-usage is not supported. > > > $ bfin-uclinux-gcc -fstack-usage -S -xc /dev/null > $ echo $? > 0 > $ bfin-uclinux-gcc -Werror -fstack-usage -S -xc /dev/null > $ echo $? > 0 > > > > Instead of /dev/null, I prepared a very simple C source code as an input. > > $ 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 > > This time we can detect unsupported -fstack-usage by the exit status. > > So, along with -Werror, I think /dev/null should also be replaced > with some _REAL_ C source file. > But my concern about this treak is we might go far from Kbuild. > In Linux Kernel, cc-option is impilemented in scripts/Kbuild.include. > It uses /dev/null as input. > I wish U-Boot would someday adopt (not nessarily the same but very > similar) Kbuild. > > If you see Linux Kernel top Makefile, > many of optional CFLAGS are provided thru cc-option and > also can be turned on/off by CONFIG_ switch. > > That is one reason I suggested to introduce CONFIG_CC_STACKUSAGE option. > But this is just my opinion and I would not necessarily stick to this idea. > Please feel free to suggest your thought. > > I tried to google this a bit, one thing I found was http://sourceware.org/bugzilla/show_bug.cgi?id=5210, but I fail to (easily) find a reliable gcc reference. Perhaps we should file a bug? -Werror doesn't work with /dev/null when -fstack-usage is not supported... I cannot comment on your concern regarding Kbuild, since I am unaware of its internals. I just suggested above since it would be a cleaner approach (if it worked...). Regards, Jeroen
Hello Jeroen > > I tried to google this a bit, one thing I found was > http://sourceware.org/bugzilla/show_bug.cgi?id=5210, but I fail > to (easily) find a reliable gcc reference. Perhaps we should > file a bug? -Werror doesn't work with /dev/null when > -fstack-usage is not supported... I might be a bug but I cannot say with confident. Anyway, we need to do something with the current gcc behavior. > I cannot comment on your concern regarding Kbuild, since I > am unaware of its internals. I just suggested above since > it would be a cleaner approach (if it worked...). I posted version2 : config.mk: disable -fstack-usage for blackfin and m68k and version3 : config.mk: fix -fstack-usage support test I think the latter is close to your idea and I believe it's better. Best Regards Masahiro Yamada
diff --git a/config.mk b/config.mk index 48913f6..177f685 100644 --- a/config.mk +++ b/config.mk @@ -117,7 +117,7 @@ CC_TEST_OFILE := $(OBJTREE)/include/generated/cc_test_file.o -include $(CC_OPTIONS_CACHE_FILE) cc-option-sys = $(shell mkdir -p $(dir $(CC_TEST_OFILE)); \ - if $(CC) $(CFLAGS) $(1) -S -xc /dev/null -o $(CC_TEST_OFILE) \ + if $(CC) -Werror $(CFLAGS) $(1) -S -xc /dev/null -o $(CC_TEST_OFILE) \