[U-Boot] config.mk: enable -fstack-usage only when it is desired

As far as I know, gcc does not support -fstack-usage
for some targets such as blackfin, m68k, microblaze, 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,

    # 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.

To suppress warnings for such targets that -fstack-usage is not supported,
this commit surrounds the concerned lines with
ifdef CONFIG_CC_STACKUSAGE .. endif.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Tom Rini <trini@ti.com>
---
 config.mk | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

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On 09/25/2013 10:17 PM, Masahiro Yamada wrote:
> As far as I know, gcc does not support -fstack-usage
> for some targets such as blackfin, m68k, microblaze, 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,
> 
>     # 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.
> 
> To suppress warnings for such targets that -fstack-usage is not supported,
> this commit surrounds the concerned lines with
> ifdef CONFIG_CC_STACKUSAGE .. endif.
> 
> Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
> Cc: Tom Rini <trini@ti.com>

The problem here is that except for whatever arches don't support
- -fstack-usage, we always want to generate this information, to assist in
debugging stack usage problems (which can be a real problem within SPL
for example).  How about ifneq($(CONFIG_M68K)$(CONFIG_...),y) ... endif
around it?

- -- 
Tom
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On 09/26/2013 01:52 PM, Tom Rini wrote:
> On 09/25/2013 10:17 PM, Masahiro Yamada wrote:
>> As far as I know, gcc does not support -fstack-usage
>> for some targets such as blackfin, m68k, microblaze, etc.

Please remove microblaze from this list.
Our gcc support fstack-usage.

If your microblaze gcc doesn't support this flag
then upgrade gcc version.

Thanks,
Michal

Hello Tom.

> The problem here is that except for whatever arches don't support
> - -fstack-usage, we always want to generate this information, to assist in
> debugging stack usage problems (which can be a real problem within SPL
> for example).  How about ifneq($(CONFIG_M68K)$(CONFIG_...),y) ... endif
> around it?

OK. This works.

But I'm kind of afraid ifneq($(CONFIG_M68K)$(CONFIG_...),y) ... endif
might be too arch-specific to be written in the top config.mk.

Instead, we can add
CONFIG_CC_STACKUSAGE=y
to arch/{arm, powerpc, x86, microblaze ...}/config.mk



Best Regards
Masahiro Yamada

Hello Michal

> Please remove microblaze from this list.
> Our gcc support fstack-usage.

I will. Thanks for helpful information!


> If your microblaze gcc doesn't support this flag
> then upgrade gcc version.

I tested microblaze-linux-gcc 4.8.0
I downloaded from ftp://ftp.kernel.org/pub/tools/crosstool/index.html

Can I get the prebuilt newer version at some download sites
or need to build from source code?


Best Regards
Masahiro Yamada

Hi,

David: Can you please tell to Masahiro where he can download
toolchain in any format which will support -fstack-usage.

I have microblazeel-xilinx-linux-gnu-gcc (crosstool-NG 1.18.0) 4.6.4 20120924 (prerelease)

Thanks,
Michal

On 09/27/2013 04:23 AM, Masahiro Yamada wrote:
> Hello Michal
> 
>> Please remove microblaze from this list.
>> Our gcc support fstack-usage.
> 
> I will. Thanks for helpful information!
> 
> 
>> If your microblaze gcc doesn't support this flag
>> then upgrade gcc version.
> 
> I tested microblaze-linux-gcc 4.8.0
> I downloaded from ftp://ftp.kernel.org/pub/tools/crosstool/index.html
> 
> Can I get the prebuilt newer version at some download sites
> or need to build from source code?
> 
> 
> Best Regards
> Masahiro Yamada
>