[OE-core] TARGET_CFLAGS for non-target builds

[Andre McCurdy]

On Mon, Feb 8, 2016 at 4:13 PM, Christopher Larson <clarson at kergoth.com> wrote:
> Target_cflags is an exported variable. It affects the checksums of every
> task. Not ideal, but that's how it is today.

So why wouldn't we just set TARGET_CFLAGS etc to "" in native.bbclass?


> On Mon, Feb 8, 2016 at 5:10 PM Andre McCurdy <armccurdy at gmail.com> wrote:
>>
>> On Mon, Feb 8, 2016 at 4:01 PM, Mark Hatle <mark.hatle at windriver.com>
>> wrote:
>> > On 2/8/16 5:43 PM, Andre McCurdy wrote:
>> >> On Mon, Feb 8, 2016 at 3:00 PM, Burton, Ross <ross.burton at intel.com>
>> >> wrote:
>> >>>
>> >>> On 8 February 2016 at 20:03, Andre McCurdy <armccurdy at gmail.com>
>> >>> wrote:
>> >>>>
>> >>>> Can you give an example? Looking at native.bbclass it seems to
>> >>>> replace
>> >>>> TARGET_CFLAGS with BUILD_CFLAGS, not manipulate it.
>> >>>
>> >>> Sure, so in doing a native build TARGET_CFLAGS is used.  But as
>> >>> security_flags.inc was using TARGET_CFLAGS_append, the end result was
>> >>> BUILD_CFLAGS appended with the security flags.
>> >>
>> >> Yes, for native, TARGET_CFLAGS will end up being "${BUILD_CFLAGS}
>> >> ${SECURITY_CFLAGS}".
>> >>
>> >> However it shouldn't matter - native.bbclass sets CFLAGS to
>> >> BUILD_CFLAGS, not TARGET_CFLAGS.
>> >>
>> >> Do you have an example where host gcc can legitimately be invoked with
>> >> TARGET_CFLAGS?
>> >
>> > You have to remember the order of the operators.  _append says to make
>> > the
>> > append, AFTER everything else has been evaluated (and before _remove).
>> > This
>> > includes override behaviors.
>> >
>> > So if you do:
>> >
>> > TARGET_CFLAGS = "-deadbeef"
>> > BUILD_CFLAGS = "-badc0ffee"
>> > TARGET_CFLAGS_append = " -foobar"
>> > TARGET_CFLAGS = "${BUILD_CFLAGS}"
>> >
>> > The final value of TARGET_CFLAGS is "-badc0ffee -foobar"
>> >
>> > Thus by changing the append to:
>> >
>> > TARGET_CFLAGS_append_class-target = " -foobar"
>> > TARGET_CFLAGS_class-native = "${BUILD_CFLAGS}"
>> >
>> > In the case where the 'class-target' is the override you will get:
>> >
>> > TARGET_CFLAGS = "-deadbeef -foobar"
>> >
>> > In the case where the 'class-native' is the override you will get:
>> >
>> > TARGET_CFLAGS = "-badc0ffee"
>>
>> I'm not disputing that TARGET_CFLAGS can contain something bogus for a
>> class-native build.
>>
>> I'm asking why does it matter?
>>
>> Setting TARGET_CFLAGS at all in native.bbclass is fairly recent and
>> seems to be a workaround to avoid churning sstate:
>>
>>
>> http://git.openembedded.org/openembedded-core/commit/?id=05a70ac30b37cab0952f1b9df501993a9dec70da
>>
>> Is that perhaps still the real reason to avoid modifying TARGET_CFLAGS
>> for a native build?
>>
>>
>> > --Mark
>> --
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