[llvm] [clang] [openmp] [OpenMP] Introduce support for OMPX extensions and taskgraph frontend (PR #66919)

[Jose Manuel Monsalve Diaz via cfe-commits]

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@@ -937,10 +937,13 @@ PRAGMA_ANNOTATION(pragma_opencl_extension)
 // distinguish between a real pragma and a converted pragma. It is not marked
 // as a PRAGMA_ANNOTATION because it doesn't get generated from a #pragma.
 ANNOTATION(attr_openmp)
+ANNOTATION(attr_openmp_extension)
 // The lexer produces these so that they only take effect when the parser
 // handles #pragma omp ... directives.
 PRAGMA_ANNOTATION(pragma_openmp)
 PRAGMA_ANNOTATION(pragma_openmp_end)
+// For support of OpenMP extensions. These tokens handle #pragma ompx ... directives
+PRAGMA_ANNOTATION(pragma_openmp_extension)
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josemonsalve2 wrote:

I implemented this part, but I couldn't find a way to reuse the tokens and maintain independence. We need to differentiate if it is an extension or not. What do you suggest we do to reuse a token and check if it is `omp` or `ompx`? 

https://github.com/llvm/llvm-project/pull/66919