David Bremner writes:
> Matthew Flatt <mfl...@cs.utah.edu> writes:
>
>> At Fri, 17 Jan 2020 09:43:15 -0400, David Bremner wrote:
>>> Matthew Flatt <mfl...@cs.utah.edu> writes:
>>> > At Fri, 17 Jan 2020 08:31:22 -0400, David Bremner wrote:
>>> >> => 0xb6ea3254 <+8>: stmdb sp!, {r4, r5, r6, r7, r8, r9, r10, r11,
>>> >> lr}
>>> >> 0xb6ea3258 <+12>: add r3, pc
>>> >
>>> > That certainly looks like a valid ARM instruction. Maybe the processor
>>> > is expecting Thumb instructions. What does `print $cpsr` report?
>>>
>>> (gdb) print $cpsr
>>> $3 = 196656
>>
>> Since bit 5 is set, I think that means the processor was expecting
>> Thumb instructions, which at least explains the error.
>>
>> To confirm that it's some bad jump or mismanagement of the mode by the
>> Racket JIT, does changing "racket/src/lightning/arm/asm.h" to disable
>> Thumb support allow the build to work?
>
> I'm not very sure I'm doing the right thing, but With the following
> change, I get the same build failure.
>
> % diff -u asm.h~ asm.h
> --- asm.h~ 2019-12-30 19:12:36.000000000 +0000
> +++ asm.h 2020-01-17 16:06:45.964573092 +0000
> @@ -2299,4 +2299,7 @@
> #define THUMB2_CLZ 0xfab0f080
> #define T2_CLZ(rd,rm) thumb2_orrr(THUMB2_CLZ,rd,rm,rm)
>
> +# undef JIT_ARM_THUMB
> +# define JIT_ARM_THUMB 0
> +
> #endif /* __lightning_asm_h */
Can you try to define that earlier?
https://github.com/racket/racket/blob/5377d00c90480e73e0863203d35d7a1dc373195d/racket/src/racket/src/lightning/arm/asm.h#L150
Remove lines 150-152 and do the same:
#undef JIT_ARM_THUMB
#define JIT_ARM_THUMB 0
It looks like this header file assumes all armv7 have thumb2 support which is
why its
generating that instruction. (line 132)
--
Paulo Matos
