clang: Emit Target Functions when #pragma omp declare target


I wanted to ask, if this behavior is on purpose or if I am missing something:

To me it seems that using "#pragma omp declare target" has no effect on the code generation.
The specification states that variables and functions are mapped to the device.
In my understanding, this means that device code should be emitted.

However, CGOpenMPRuntime::emitTargetGlobal() does only search for target #pragmas and doesn't check for OMPDeclareTargetDeclAttr. This check is done in ASTContext::DeclMustBeEmitted(), but it seems, this can never happen. The reason is that CodeGenModule::EmitGlobal() returns early after calling CGOpenMPRuntime::emitTargetGlobal(). I hope, this is understandable.

It might be that this problem never showed up when the device is x86 as well. But I don't understand how Nvidia can compile e.g. lulesh like this...

My question is if the intended way would be to change emitTargetGlobal() to also emit functions/variables with OMPDeclareTargetDeclAttr.

Thanks in advance,

Hi Daniel,

I think Clang trunk doesn't yet have full codegen support for the declare target directive. Please see for a document with the current implementation status.