[oe] [meta-qt5] why does Qt5 build with ARM_INSTRUCTION_SET = "arm"

[Andre McCurdy]

On Mon, Feb 17, 2014 at 3:03 PM, Martin Jansa <martin.jansa at gmail.com> wrote:
> On Mon, Feb 17, 2014 at 04:46:23PM -0500, Denys Dmytriyenko wrote:
>> On Mon, Feb 17, 2014 at 02:27:51PM -0700, Nicolas Dechesne wrote:
>> > hi,
>> >
>> > does anybody know why in Qt5/qtbase.inc, we have:
>> >
>> > ARM_INSTRUCTION_SET = "arm"
>> >
>> > Could it be an a low hanging fruit from the past? e.g. before
>> > https://bugreports.qt-project.org/browse/QTBUG-16402 or
>> > https://qt.gitorious.org/qt/qtbase/commit/a3bd9d4c0f3d9e80dbe35bd88649b245dca5f410?
>>
>> Hmm, I would assume that's here from 4.8 days, although I haven't tried
>> dropping that line for latest Qt5... Would make sense to do some more testing.
>>
>> > as a matter of fact, for our project Qt5 (and QtWebkit) are building
>> > (and working fine) when built with Thumb2, outside of OE. Also using
>> > ARM instruction set instead of Thumb2 enforces Webkit to use the ARM
>> > version of the javascript JIT, while the Thumb2 JIT engine seems to
>> > work a lot better in our testing...
>>
>> Seems like worth the effort to re-test the need for that setting. Unless
>> someone else has tried it already and found out the issue is still there
>
> IIRC it was failing to build for armv4t (at least with 5.0.0) if someone
> tests that armv4t builds with 5.2.*, I'll accept the patch.

With ARM_INSTRUCTION_SET forced to thumb I'm able to build qtbase
5.1.1 and 5.2.1 tuned for both armv4t and cortexa9thf-neon.

Andre
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