[Mesa-dev] [PATCH] gallivm: fix issue with AtomicCmpXchg wrapper on llvm 3.5-3.8

[Roland Scheidegger]

Am 02.08.19 um 18:54 schrieb Brian Paul:
> On 08/02/2019 10:36 AM, sroland at vmware.com wrote:
>> From: Roland Scheidegger <sroland at vmware.com>
>>
>> These versions still need wrapper but already have both success and
>> failure ordering.
>> (Compile tested on llvm 3.7, llvm 3.8.)
>>
>> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111102
>> ---
>>   src/gallium/auxiliary/gallivm/lp_bld_misc.cpp | 16 +++++++++++++++-
>>   1 file changed, 15 insertions(+), 1 deletion(-)
>>
>> diff --git a/src/gallium/auxiliary/gallivm/lp_bld_misc.cpp
>> b/src/gallium/auxiliary/gallivm/lp_bld_misc.cpp
>> index 79d10293e80..723c84d57c2 100644
>> --- a/src/gallium/auxiliary/gallivm/lp_bld_misc.cpp
>> +++ b/src/gallium/auxiliary/gallivm/lp_bld_misc.cpp
>> @@ -822,15 +822,29 @@ static llvm::AtomicOrdering
>> mapFromLLVMOrdering(LLVMAtomicOrdering Ordering) {
>>      llvm_unreachable("Invalid LLVMAtomicOrdering value!");
>>   }
>>   +#if HAVE_LLVM < 0x305
>>   LLVMValueRef LLVMBuildAtomicCmpXchg(LLVMBuilderRef B, LLVMValueRef Ptr,
>>                                       LLVMValueRef Cmp, LLVMValueRef New,
>>                                       LLVMAtomicOrdering SuccessOrdering,
>>                                       LLVMAtomicOrdering FailureOrdering,
>>                                       LLVMBool SingleThread)
>>   {
>> -   /* LLVM 3.8 doesn't have a second ordering and uses old
>> SynchronizationScope enum */
>> +   /* LLVM < 3.5 doesn't have a second ordering and uses old
>> SynchronizationScope enum */
>>      return
>> llvm::wrap(llvm::unwrap(B)->CreateAtomicCmpXchg(llvm::unwrap(Ptr),
>> llvm::unwrap(Cmp),
>>                                                            
>> llvm::unwrap(New), mapFromLLVMOrdering(SuccessOrdering),
>>                                                            
>> SingleThread ? llvm::SynchronizationScope::SingleThread :
>> llvm::SynchronizationScope::CrossThread));
>>   }
>> +#else
>> +LLVMValueRef LLVMBuildAtomicCmpXchg(LLVMBuilderRef B, LLVMValueRef Ptr,
>> +                                    LLVMValueRef Cmp, LLVMValueRef New,
>> +                                    LLVMAtomicOrdering SuccessOrdering,
>> +                                    LLVMAtomicOrdering FailureOrdering,
>> +                                    LLVMBool SingleThread)
>> +{
>> +   return
>> llvm::wrap(llvm::unwrap(B)->CreateAtomicCmpXchg(llvm::unwrap(Ptr),
>> llvm::unwrap(Cmp),
>> +                                                         
>> llvm::unwrap(New), mapFromLLVMOrdering(SuccessOrdering),
>> +                                                         
>> mapFromLLVMOrdering(FailureOrdering),
>> +                                                         
>> SingleThread ? llvm::SynchronizationScope::SingleThread :
>> llvm::SynchronizationScope::CrossThread));
>> +}
>> +#endif
>>   #endif
>>
> 
> Could the #if / #endif logic be moved into the body of
> LLVMBuildAtomicCmpXchg() so the whole function isn't duplicated?
Ah yes sure. Somehow I didn't think of that...
Will change this before submit.

Roland


> 
> Other than that,
> Reviewed-by: Brian Paul <brianp at vmware.com>