[CUDA] CUDA has no device-side library builtins.

We should (almost) never consider a device-side declaration to match a
library builtin functio.  Otherwise clang may ignore the implementation
provided by the CUDA headers and emit clang's idea of the builtin.

Differential Revision: https://reviews.llvm.org/D42319

llvm-svn: 323239

1 files changed, 7 insertions, 0 deletions

diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
index 918466236bf..f8010695c90 100644
--- a/clang/lib/AST/Decl.cpp
+++ b/clang/lib/AST/Decl.cpp
@@ -2901,6 +2901,13 @@ unsigned FunctionDecl::getBuiltinID() const {
       Context.BuiltinInfo.isPredefinedLibFunction(BuiltinID))
     return 0;
 
+  // CUDA does not have device-side standard library. printf and malloc are the
+  // only special cases that are supported by device-side runtime.
+  if (Context.getLangOpts().CUDA && hasAttr<CUDADeviceAttr>() &&
+      !hasAttr<CUDAHostAttr>() &&
+      !(BuiltinID == Builtin::BIprintf || BuiltinID == Builtin::BImalloc))
+    return 0;
+
   return BuiltinID;
 }