[clang] [SYCL] SYCL host kernel launch support for the sycl_kernel_entry_point attribute. (PR #152403)

[Mariya Podchishchaeva via cfe-commits]

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@@ -387,8 +397,162 @@ void SemaSYCL::CheckSYCLEntryPointFunctionDecl(FunctionDecl *FD) {
   }
 }
 
+ExprResult SemaSYCL::BuildSYCLKernelLaunchIdExpr(FunctionDecl *FD,
+                                                 QualType KNT) {
+  // The current context must be the function definition context to ensure
+  // that name lookup is performed within the correct scope.
+  assert(SemaRef.CurContext == FD);
+
+  // An appropriate source location is required to emit diagnostics if
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Fznamznon wrote:

I think the issue I had while developing this with invalid source locations is that validity of a source location sometimes used to understand whether is something present, like a valid source location of a `<` token may indicate that an explicit template parameter is passed. 

https://github.com/llvm/llvm-project/pull/152403