[OpenCL][CUDA][HIP][SYCL] Add norecurse

norecurse function attr indicates the function is not called recursively
directly or indirectly.

Add norecurse to OpenCL functions, SYCL functions in device compilation
and CUDA/HIP kernels.

Although there is LLVM pass adding norecurse to functions, it only works
for whole-program compilation. Also FE adding norecurse can make that
pass run faster since functions with norecurse do not need to be checked
again.

Differential Revision: https://reviews.llvm.org/D73651

1 files changed, 14 insertions, 4 deletions

diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index bcd9366..d6c2afc 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -918,10 +918,20 @@ void CodeGenFunction::StartFunction(GlobalDecl GD, QualType RetTy,
   // If we're in C++ mode and the function name is "main", it is guaranteed
   // to be norecurse by the standard (3.6.1.3 "The function main shall not be
   // used within a program").
-  if (getLangOpts().CPlusPlus)
-    if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D))
-      if (FD->isMain())
-        Fn->addFnAttr(llvm::Attribute::NoRecurse);
+  //
+  // OpenCL C 2.0 v2.2-11 s6.9.i:
+  //     Recursion is not supported.
+  //
+  // SYCL v1.2.1 s3.10:
+  //     kernels cannot include RTTI information, exception classes,
+  //     recursive code, virtual functions or make use of C++ libraries that
+  //     are not compiled for the device.
+  if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D)) {
+    if ((getLangOpts().CPlusPlus && FD->isMain()) || getLangOpts().OpenCL ||
+        getLangOpts().SYCLIsDevice ||
+        (getLangOpts().CUDA && FD->hasAttr<CUDAGlobalAttr>()))
+      Fn->addFnAttr(llvm::Attribute::NoRecurse);
+  }
 
   if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D))
     if (FD->usesFPIntrin())