From 508503d91b95d9c6e365c492133bee452cbc06ba Mon Sep 17 00:00:00 2001
From: Tom Honermann <tom.honermann@intel.com>
Date: Fri, 19 Dec 2025 15:19:34 -0800
Subject: [PATCH] [Clang][SYCL] Modify err_sycl_entry_point_invalid to use
 %enum_select.

The `err_sycl_entry_point_invalid` diagnostic has a selection field
for which there are already many options with more expected to be
added. Use of %enum_select avoids the need for magic numbers with
associated comments at source locations where the diagnostic is
issued.
---
 clang/include/clang/Basic/DiagnosticSemaKinds.td | 16 +++++++++++-----
 clang/lib/Sema/SemaDecl.cpp                      |  8 ++++----
 clang/lib/Sema/SemaSYCL.cpp                      | 14 +++++++-------
 3 files changed, 22 insertions(+), 16 deletions(-)

diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 51b6eba965103..c9902a372e846 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -13170,11 +13170,17 @@ def warn_sycl_external_missing_on_first_decl : Warning<
 
 // SYCL kernel entry point diagnostics
 def err_sycl_entry_point_invalid : Error<
-  "the %0 attribute cannot be applied to a"
-  " %select{non-static member function|variadic function|deleted function|"
-           "defaulted function|constexpr function|consteval function|"
-           "function declared with the 'noreturn' attribute|coroutine|"
-           "function defined with a function try block}1">;
+  "the %0 attribute cannot be applied to a %enum_select<InvalidSKEPReason>{"
+      "%NonStaticMemberFn{non-static member function}|"
+      "%VariadicFn{variadic function}|"
+      "%DeletedFn{deleted function}|"
+      "%DefaultedFn{defaulted function}|"
+      "%ConstexprFn{constexpr function}|"
+      "%ConstevalFn{consteval function}|"
+      "%NoreturnFn{function declared with the 'noreturn' attribute}|"
+      "%Coroutine{coroutine}|"
+      "%FunctionTryBlock{function defined with a function try block}"
+      "}1">;
 def err_sycl_entry_point_invalid_redeclaration : Error<
   "the %0 kernel name argument does not match prior"
   " declaration%diff{: $ vs $|}1,2">;
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 72039cc164d88..5da665a5acad2 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -16468,19 +16468,19 @@ Decl *Sema::ActOnFinishFunctionBody(Decl *dcl, Stmt *Body, bool IsInstantiation,
         FD->getAttr<SYCLKernelEntryPointAttr>();
     if (FD->isDefaulted()) {
       Diag(SKEPAttr->getLocation(), diag::err_sycl_entry_point_invalid)
-          << SKEPAttr << /*defaulted function*/ 3;
+          << SKEPAttr << diag::InvalidSKEPReason::DefaultedFn;
       SKEPAttr->setInvalidAttr();
     } else if (FD->isDeleted()) {
       Diag(SKEPAttr->getLocation(), diag::err_sycl_entry_point_invalid)
-          << SKEPAttr << /*deleted function*/ 2;
+          << SKEPAttr << diag::InvalidSKEPReason::DeletedFn;
       SKEPAttr->setInvalidAttr();
     } else if (FSI->isCoroutine()) {
       Diag(SKEPAttr->getLocation(), diag::err_sycl_entry_point_invalid)
-          << SKEPAttr << /*coroutine*/ 7;
+          << SKEPAttr << diag::InvalidSKEPReason::Coroutine;
       SKEPAttr->setInvalidAttr();
     } else if (Body && isa<CXXTryStmt>(Body)) {
       Diag(SKEPAttr->getLocation(), diag::err_sycl_entry_point_invalid)
-          << SKEPAttr << /*function defined with a function try block*/ 8;
+          << SKEPAttr << diag::InvalidSKEPReason::FunctionTryBlock;
       SKEPAttr->setInvalidAttr();
     }
 
diff --git a/clang/lib/Sema/SemaSYCL.cpp b/clang/lib/Sema/SemaSYCL.cpp
index 67f3856c10615..280f9b1a4b42d 100644
--- a/clang/lib/Sema/SemaSYCL.cpp
+++ b/clang/lib/Sema/SemaSYCL.cpp
@@ -318,40 +318,40 @@ void SemaSYCL::CheckSYCLEntryPointFunctionDecl(FunctionDecl *FD) {
   if (const auto *MD = dyn_cast<CXXMethodDecl>(FD)) {
     if (!MD->isStatic()) {
       Diag(SKEPAttr->getLocation(), diag::err_sycl_entry_point_invalid)
-          << SKEPAttr << /*non-static member function*/ 0;
+          << SKEPAttr << diag::InvalidSKEPReason::NonStaticMemberFn;
       SKEPAttr->setInvalidAttr();
     }
   }
 
   if (FD->isVariadic()) {
     Diag(SKEPAttr->getLocation(), diag::err_sycl_entry_point_invalid)
-        << SKEPAttr << /*variadic function*/ 1;
+        << SKEPAttr << diag::InvalidSKEPReason::VariadicFn;
     SKEPAttr->setInvalidAttr();
   }
 
   if (FD->isDefaulted()) {
     Diag(SKEPAttr->getLocation(), diag::err_sycl_entry_point_invalid)
-        << SKEPAttr << /*defaulted function*/ 3;
+        << SKEPAttr << diag::InvalidSKEPReason::DefaultedFn;
     SKEPAttr->setInvalidAttr();
   } else if (FD->isDeleted()) {
     Diag(SKEPAttr->getLocation(), diag::err_sycl_entry_point_invalid)
-        << SKEPAttr << /*deleted function*/ 2;
+        << SKEPAttr << diag::InvalidSKEPReason::DeletedFn;
     SKEPAttr->setInvalidAttr();
   }
 
   if (FD->isConsteval()) {
     Diag(SKEPAttr->getLocation(), diag::err_sycl_entry_point_invalid)
-        << SKEPAttr << /*consteval function*/ 5;
+        << SKEPAttr << diag::InvalidSKEPReason::ConstevalFn;
     SKEPAttr->setInvalidAttr();
   } else if (FD->isConstexpr()) {
     Diag(SKEPAttr->getLocation(), diag::err_sycl_entry_point_invalid)
-        << SKEPAttr << /*constexpr function*/ 4;
+        << SKEPAttr << diag::InvalidSKEPReason::ConstexprFn;
     SKEPAttr->setInvalidAttr();
   }
 
   if (FD->isNoReturn()) {
     Diag(SKEPAttr->getLocation(), diag::err_sycl_entry_point_invalid)
-        << SKEPAttr << /*function declared with the 'noreturn' attribute*/ 6;
+        << SKEPAttr << diag::InvalidSKEPReason::NoreturnFn;
     SKEPAttr->setInvalidAttr();
   }