[CUDA][HIP] make trivial ctor/dtor host device (#72394)

Make trivial ctor/dtor implicitly host device functions so that they can
be used to initialize file-scope
device variables to match nvcc behavior.

Fixes: https://github.com/llvm/llvm-project/issues/72261

Fixes: SWDEV-432412

1 files changed, 16 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaCUDA.cpp b/clang/lib/Sema/SemaCUDA.cpp
index 318174f..b94f448 100644
--- a/clang/lib/Sema/SemaCUDA.cpp
+++ b/clang/lib/Sema/SemaCUDA.cpp
@@ -772,6 +772,22 @@ void Sema::maybeAddCUDAHostDeviceAttrs(FunctionDecl *NewD,
   NewD->addAttr(CUDADeviceAttr::CreateImplicit(Context));
 }
 
+// If a trivial ctor/dtor has no host/device
+// attributes, make it implicitly host device function.
+void Sema::maybeAddCUDAHostDeviceAttrsToTrivialCtorDtor(FunctionDecl *FD) {
+  bool IsTrivialCtor = false;
+  if (auto *CD = dyn_cast<CXXConstructorDecl>(FD))
+    IsTrivialCtor = isEmptyCudaConstructor(SourceLocation(), CD);
+  bool IsTrivialDtor = false;
+  if (auto *DD = dyn_cast<CXXDestructorDecl>(FD))
+    IsTrivialDtor = isEmptyCudaDestructor(SourceLocation(), DD);
+  if ((IsTrivialCtor || IsTrivialDtor) && !FD->hasAttr<CUDAHostAttr>() &&
+      !FD->hasAttr<CUDADeviceAttr>()) {
+    FD->addAttr(CUDAHostAttr::CreateImplicit(Context));
+    FD->addAttr(CUDADeviceAttr::CreateImplicit(Context));
+  }
+}
+
 // TODO: `__constant__` memory may be a limited resource for certain targets.
 // A safeguard may be needed at the end of compilation pipeline if
 // `__constant__` memory usage goes beyond limit.