[OE-core] TARGET_CFLAGS for non-target builds

[Andre McCurdy]

On Mon, Feb 8, 2016 at 4:29 PM, Andre McCurdy <armccurdy at gmail.com> wrote:
> 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?

... with an appropriate over-ride for SECURITY_CFLAGS too.

>
>
>> 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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