[Mesa-dev] [PATCH] gallivm: use llvm jit code for decoding s3tc

[Michel Dänzer]

On 2018-12-19 4:51 a.m., sroland at vmware.com wrote:
> From: Roland Scheidegger <sroland at vmware.com>
> 
> This is (much) faster than using the util fallback.
> (Note that there's two methods here, one would use a cache, similar to
> the existing code (although the cache was disabled), except the block
> decode is done with jit code, the other directly decodes the required
> pixels. For now don't use the cache (being direct-mapped is suboptimal,
> but it's difficult to come up with something better which doesn't have
> too much overhead.)

This change made lp_test_format segfault on my Ryzen 7 1700, both using
LLVM 7 and current SVN HEAD. Not much information in the backtrace
unfortunately:

Program received signal SIGSEGV, Segmentation fault.
0x0000000000000000 in ?? ()
(gdb) bt
#0  0x0000000000000000 in ?? ()
#1  0x00007ffff7fcd16a in ?? ()
#2  0x2c2c2c2caeaeaeae in ?? ()
#3  0x979797976f6f6f6f in ?? ()
#4  0x000020b00000d7f2 in ?? ()
#5  0x0000976f00002cae in ?? ()
#6  0x0089625d008eb099 in ?? ()
#7  0x7b8487218483a821 in ?? ()
#8  0x008414210094ffd6 in ?? ()
#9  0x007bef9400739629 in ?? ()
#10 0x0000000000000069 in ?? ()
#11 0x00000000000006d0 in ?? ()
#12 0x00007fffffffe490 in ?? ()
#13 0x000055555593f040 in ?? ()
#14 0x00007fffffffe430 in ?? ()
#15 0x00007ffff7fcd053 in ?? ()
#16 0x00007ffff7fcd000 in ?? ()
#17 0x00005555556fd618 in util_format_test_cases ()
#18 0x00005555558c0780 in ?? ()
#19 0x00007fffffffe490 in ?? ()
#20 0x00005555556fd618 in util_format_test_cases ()
#21 0x00005555555667cc in test_format_float (verbose=<optimized out>, desc=0x7fffffffe4a0, fp=0x0) at ../src/gallium/drivers/llvmpipe/lp_test_format.c:184
#22 test_one (verbose=<optimized out>, format_desc=0x7fffffffe4a0, fp=0x0) at ../src/gallium/drivers/llvmpipe/lp_test_format.c:342
#23 test_all (verbose=<optimized out>, fp=0x0) at ../src/gallium/drivers/llvmpipe/lp_test_format.c:395
#24 0x000055555556621f in main (argc=1, argv=0x7fffffffe628) at ../src/gallium/drivers/llvmpipe/lp_test_main.c:419


-- 
Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer