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

[Jose Fonseca]

There's an function -- LLVMGetIntrinsicID -- I wonder if we can use it 
to trap unsupported intrinsics?

Jose

On 20/12/2018 22:09, Roland Scheidegger wrote:
> Am 20.12.18 um 16:56 schrieb 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:
>>
> 
> Ahh I failed to test with newer llvm versions (it works with llvm 5.0 at
> least).
> It is (once again...) due to intrinsics disappearing from llvm.
> I especially hate it that there's seemingly no way to detect if an
> intrinsic has disappeared, since llvm will just replace it will calls to
> address 0 if the intrinsic doesn't exist nowadays...
> Probably it's the llvm.x86.sse2.pavg.b intrinsic, I'll fix it...
> 
> Roland
> 
> 
> 
>> 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
>>
>>
>