[clang] [clang][SYCL] Diagnose reference kernel parameters (PR #192957)

[Mariya Podchishchaeva via cfe-commits]

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@@ -665,6 +666,109 @@ OutlinedFunctionDecl *BuildSYCLKernelEntryPointOutline(Sema &SemaRef,
   return OFD;
 }
 
+class KernelParamsChecker : public ConstSubobjectVisitor<KernelParamsChecker> {
+  SemaSYCL &SemaSYCLRef;
+  bool IsValid = true;
+  using ObjectAccess =
+      llvm::PointerUnion<const ParmVarDecl *, const CXXBaseSpecifier *,
+                         const FieldDecl *>;
+  SmallVector<ObjectAccess, 4> ObjectAccessPath;
+
+  void emitObjectAccessPathNotes() {
+    for (auto Parent : llvm::reverse(ObjectAccessPath)) {
+      if (auto *FD = Parent.dyn_cast<const FieldDecl *>()) {
+        const CXXRecordDecl *ParentRD = cast<CXXRecordDecl>(FD->getParent());
+        if (ParentRD->isLambda()) {
+          SemaSYCLRef.Diag(ParentRD->getLocation(), diag::note_within_capture)
+              << ParentRD->getCapture(FD->getFieldIndex())->getCapturedVar();
+        } else {
+          SemaSYCLRef.Diag(ParentRD->getLocation(),
+                           diag::note_within_field_of_type)
+              << ParentRD;
+        }
+      } else if (auto *BS = Parent.dyn_cast<const CXXBaseSpecifier *>()) {
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Fznamznon wrote:

And here

https://github.com/llvm/llvm-project/pull/192957