[Mesa-dev] [PATCH] gallivm: abort when trying to use non-existing intrinsic

[Roland Scheidegger]

Am 21.12.18 um 15:30 schrieb Jose Fonseca:
> On 21/12/2018 14:28, Roland Scheidegger wrote:
>> Am 21.12.18 um 08:46 schrieb Jose Fonseca:
>>> On 21/12/2018 01:42, sroland at vmware.com wrote:
>>>> From: Roland Scheidegger <sroland at vmware.com>
>>>>
>>>> Whenever llvm removes an intrinsic (we're using), we're hitting
>>>> segfaults
>>>> due to llvm doing calls to address 0 in the jitted code instead.
>>>> However, Jose figured out we can actually detect this with
>>>> LLVMGetIntrinsicID(), so use this to abort, so we don't have to wonder
>>>> what got broken. (Of course, someone still needs to fix the code to
>>>> no longer use this intrinsic.)
>>>> ---
>>>>    src/gallium/auxiliary/gallivm/lp_bld_intr.c | 10 ++++++++++
>>>>    1 file changed, 10 insertions(+)
>>>>
>>>> diff --git a/src/gallium/auxiliary/gallivm/lp_bld_intr.c
>>>> b/src/gallium/auxiliary/gallivm/lp_bld_intr.c
>>>> index 74ed16f33f0..c9df136b103 100644
>>>> --- a/src/gallium/auxiliary/gallivm/lp_bld_intr.c
>>>> +++ b/src/gallium/auxiliary/gallivm/lp_bld_intr.c
>>>> @@ -241,6 +241,16 @@ lp_build_intrinsic(LLVMBuilderRef builder,
>>>>            function = lp_declare_intrinsic(module, name, ret_type,
>>>> arg_types, num_args);
>>>>    +      /*
>>>> +       * If llvm removes an intrinsic we use, we'll hit this abort
>>>> (rather
>>>> +       * than a call to address zero in the jited code).
>>>> +       */
>>>> +      if (LLVMGetIntrinsicID(function) == 0) {
>>>> +         printf("llvm (version 0x%x) found no intrinsic for %s, going
>>>> to crash...\n",
>>>> +                HAVE_LLVM, name);
>>>
>>> Better to use _debug_printf() so it's redirected to stderr (or
>>> OutpuDebug on Windows.)
>> Alright, though this will drop the output on non-debug builds.
> 
> Not really: debug_printf only prints on debug build, but  _debug_printf
> (note the leading underscore) always print.
Ahh right I failed to catch the difference here.

Roland



> 
> Perhaps it's not the smartest naming convention, but it should do the
> expected.
> 
> 
> Jose