[clang] [clang] Fix device_kernel attribute crash on unsupported targets when not using AMDGPU spelling (PR #161687)

[via cfe-commits]

https://github.com/camc updated https://github.com/llvm/llvm-project/pull/161687

>From 4333cfba6839672c6bebb510f2b42e847a5fa7c5 Mon Sep 17 00:00:00 2001
From: camc <pushy-crop-cartel at duck.com>
Date: Thu, 2 Oct 2025 15:15:35 +0000
Subject: [PATCH 1/2] [clang] Fix device_kernel attribute crash on unsupported
 targets when not using AMDGPU spelling

---
 clang/lib/Sema/SemaDeclAttr.cpp | 6 +++++-
 clang/lib/Sema/SemaType.cpp     | 2 +-
 clang/test/Sema/callingconv.c   | 4 ++++
 3 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
index a8dfa4d7df2d5..979ca03e9867e 100644
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -5204,7 +5204,11 @@ static void handleCallConvAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
 static void handleDeviceKernelAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
   const auto *FD = dyn_cast_or_null<FunctionDecl>(D);
   bool IsFunctionTemplate = FD && FD->getDescribedFunctionTemplate();
-  if (S.getLangOpts().SYCLIsDevice) {
+  if (!S.getLangOpts().OpenCL && !S.getLangOpts().CUDA && !DeviceKernelAttr::isAMDGPUSpelling(AL)) {
+    // This is already diagnosed for AMDGPU in getCCForDeclaratorChunk
+    S.Diag(AL.getLoc(), diag::warn_cconv_unsupported)
+        << AL << (int)Sema::CallingConventionIgnoredReason::ForThisTarget;
+  } else if (S.getLangOpts().SYCLIsDevice) {
     if (!IsFunctionTemplate) {
       S.Diag(AL.getLoc(), diag::warn_attribute_wrong_decl_type_str)
           << AL << AL.isRegularKeywordAttribute() << "function templates";
diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index bee613aa5f1c5..aaa92b238376c 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -3780,7 +3780,7 @@ static CallingConv getCCForDeclaratorChunk(
       }
     }
   }
-  if (!S.getLangOpts().isSYCL()) {
+  if (S.getLangOpts().OpenCL || S.getLangOpts().CUDA) {
     for (const ParsedAttr &AL : D.getDeclSpec().getAttributes()) {
       if (AL.getKind() == ParsedAttr::AT_DeviceKernel) {
         CC = CC_DeviceKernel;
diff --git a/clang/test/Sema/callingconv.c b/clang/test/Sema/callingconv.c
index f0b8b80a32974..2ea8757526666 100644
--- a/clang/test/Sema/callingconv.c
+++ b/clang/test/Sema/callingconv.c
@@ -55,6 +55,10 @@ int __attribute__((aarch64_vector_pcs)) aavpcs(void); // expected-warning {{'aar
 int __attribute__((aarch64_sve_pcs)) aasvepcs(void);  // expected-warning {{'aarch64_sve_pcs' calling convention is not supported for this target}}
 
 int __attribute__((amdgpu_kernel)) amdgpu_kernel(void); // expected-warning {{'amdgpu_kernel' calling convention is not supported for this target}}
+int __attribute__((device_kernel)) device_kernel(void) { // expected-warning {{'device_kernel' calling convention is not supported for this target}}
+}
+int __attribute__((sycl_kernel)) sycl_kernel(void) { // expected-warning {{'sycl_kernel' calling convention is not supported for this target}}
+}
 
 // PR6361
 void ctest3();

>From 624482b6bbbf0d90294f641bb14b9b5b3b038cae Mon Sep 17 00:00:00 2001
From: camc <pushy-crop-cartel at duck.com>
Date: Thu, 2 Oct 2025 15:27:31 +0000
Subject: [PATCH 2/2] add release note

---
 clang/docs/ReleaseNotes.rst | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index e8deae50e4cb0..69f7341c20372 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -397,6 +397,8 @@ Bug Fixes to Attribute Support
 - Using ``[[gnu::cleanup(some_func)]]`` where some_func is annotated with
   ``[[gnu::error("some error")]]`` now correctly triggers an error. (#GH146520)
 - Fix a crash when the function name is empty in the `swift_name` attribute. (#GH157075)
+- Fix a crash and missing diagnostic when using some device_kernel attributes in
+  unsupported targets. (#GH161077)
 
 Bug Fixes to C++ Support
 ^^^^^^^^^^^^^^^^^^^^^^^^