[CUDA] Assume the latest known CUDA version if we've found an unknown one.

This makes clang somewhat forward-compatible with new CUDA releases
without having to patch it for every minor release without adding
any new function.

If an unknown version is found, clang issues a warning (can be disabled
with -Wno-cuda-unknown-version) and assumes that it has detected
the latest known version. CUDA releases are usually supersets
of older ones feature-wise, so it should be sufficient to keep
released clang versions working with minor CUDA updates without
having to upgrade clang, too.

Differential Revision: https://reviews.llvm.org/D73231

(cherry picked from commit 12fefeef203ab4ef52d19bcdbd4180608a4deae1)

1 files changed, 5 insertions, 3 deletions

diff --git a/clang/lib/Basic/Cuda.cpp b/clang/lib/Basic/Cuda.cpp
index f2b6c8cd3ee..e06d120c58b 100644
--- a/clang/lib/Basic/Cuda.cpp
+++ b/clang/lib/Basic/Cuda.cpp
@@ -2,6 +2,7 @@
 
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/StringSwitch.h"
+#include "llvm/ADT/Twine.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/VersionTuple.h"
 
@@ -31,8 +32,8 @@ const char *CudaVersionToString(CudaVersion V) {
   llvm_unreachable("invalid enum");
 }
 
-CudaVersion CudaStringToVersion(llvm::StringRef S) {
-  return llvm::StringSwitch<CudaVersion>(S)
+CudaVersion CudaStringToVersion(const llvm::Twine &S) {
+  return llvm::StringSwitch<CudaVersion>(S.str())
       .Case("7.0", CudaVersion::CUDA_70)
       .Case("7.5", CudaVersion::CUDA_75)
       .Case("8.0", CudaVersion::CUDA_80)
@@ -40,7 +41,8 @@ CudaVersion CudaStringToVersion(llvm::StringRef S) {
       .Case("9.1", CudaVersion::CUDA_91)
       .Case("9.2", CudaVersion::CUDA_92)
       .Case("10.0", CudaVersion::CUDA_100)
-      .Case("10.1", CudaVersion::CUDA_101);
+      .Case("10.1", CudaVersion::CUDA_101)
+      .Default(CudaVersion::UNKNOWN);
 }
 
 const char *CudaArchToString(CudaArch A) {