Bug 205663 Clang getting Bus Errors (arm SCLTR Bit[12]==1 context): Reported fixed on llvm's trunk

[Ian Lepore]

On Sat, 2016-01-09 at 15:03 +0100, Dimitry Andric wrote:
> On 09 Jan 2016, at 04:46, Mark Millard <markmi at dsl-only.net> wrote:
> > 
> > On 2016-Jan-7, at 2:57 PM, Dimitry Andric <dim at FreeBSD.org>
> > wrote:
> ...
> > > FYI, I have added a -mno-movt option for this purpose upstream,
> > > and
> > > imported a newer snapshot into the clang380-import branch.  As of
> > > r293384, it now uses the new option spelling for modules, if your
> > > clang
> > > is 3.8.0 or higher.
> > > 
> > > -Dimitry
> > 
> > I've not been able to get to the point of running clang++ 3.8 on
> > the rpi2 yet: R_ARM_CALL and R_ARM_JUMP24 relocation truncations
> > during the cross build's buildworld interfere.
> 
> Yes, this is caused by too large call distances.  In other words, the
> clang executable is getting to big to link.  Apparently we need to do
> some tricks with -mlongcall to fix this.  As I am no arm expert, I
> welcome any patch submissions. :-)
> 
> -Dimitry
> 

Here's the patch I got from Andy for the clang380 branch, modified with
Warner's suggestion to use MACHINE_CPUARCH instead of MACHINE.  With
this I can get a working arm world that will build a runnable
helloworld.c (and .cc) on a dreamplug.  (I.e., it appears clang 3.8.0
fixes the problem we had with clang 3.7.x where it wouldn't run at all
on armv4/5 systems).  I have not tried compling anything complex yet.

-- Ian
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