[HIP] Emit kernel symbol

Currently clang uses stub function to launch kernel. This is inconvenient
to interop with C++ programs since the stub function has different name
as kernel, which is required by ROCm debugger.

This patch emits a variable symbol which has the same name as the kernel
and uses it to register and launch the kernel. This allows C++ program to
launch a kernel by using the original kernel name.

Reviewed by: Artem Belevich

Differential Revision: https://reviews.llvm.org/D86376

1 files changed, 13 insertions, 3 deletions

diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 0d499a564039..750439dd6844 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -3571,9 +3571,19 @@ llvm::Constant *CodeGenModule::GetAddrOfFunction(GlobalDecl GD,
   }
 
   StringRef MangledName = getMangledName(GD);
-  return GetOrCreateLLVMFunction(MangledName, Ty, GD, ForVTable, DontDefer,
-                                 /*IsThunk=*/false, llvm::AttributeList(),
-                                 IsForDefinition);
+  auto *F = GetOrCreateLLVMFunction(MangledName, Ty, GD, ForVTable, DontDefer,
+                                    /*IsThunk=*/false, llvm::AttributeList(),
+                                    IsForDefinition);
+  // Returns kernel handle for HIP kernel stub function.
+  if (LangOpts.CUDA && !LangOpts.CUDAIsDevice &&
+      cast<FunctionDecl>(GD.getDecl())->hasAttr<CUDAGlobalAttr>()) {
+    auto *Handle = getCUDARuntime().getKernelHandle(
+        cast<llvm::Function>(F->stripPointerCasts()), GD);
+    if (IsForDefinition)
+      return F;
+    return llvm::ConstantExpr::getBitCast(Handle, Ty->getPointerTo());
+  }
+  return F;
 }
 
 static const FunctionDecl *