[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, 15 insertions, 28 deletions

diff --git a/clang/lib/Driver/ToolChains/Cuda.cpp b/clang/lib/Driver/ToolChains/Cuda.cpp
index 02871d2ce41..8a7da4f86b3 100644
--- a/clang/lib/Driver/ToolChains/Cuda.cpp
+++ b/clang/lib/Driver/ToolChains/Cuda.cpp
@@ -32,37 +32,24 @@ using namespace llvm::opt;
 
 // Parses the contents of version.txt in an CUDA installation.  It should
 // contain one line of the from e.g. "CUDA Version 7.5.2".
-static CudaVersion ParseCudaVersionFile(llvm::StringRef V) {
+static CudaVersion ParseCudaVersionFile(const Driver &D, llvm::StringRef V) {
   if (!V.startswith("CUDA Version "))
     return CudaVersion::UNKNOWN;
   V = V.substr(strlen("CUDA Version "));
-  int Major = -1, Minor = -1;
-  auto First = V.split('.');
-  auto Second = First.second.split('.');
-  if (First.first.getAsInteger(10, Major) ||
-      Second.first.getAsInteger(10, Minor))
+  SmallVector<StringRef,4> VersionParts;
+  V.split(VersionParts, '.');
+  if (VersionParts.size() < 2)
     return CudaVersion::UNKNOWN;
-
-  if (Major == 7 && Minor == 0) {
-    // This doesn't appear to ever happen -- version.txt doesn't exist in the
-    // CUDA 7 installs I've seen.  But no harm in checking.
-    return CudaVersion::CUDA_70;
-  }
-  if (Major == 7 && Minor == 5)
-    return CudaVersion::CUDA_75;
-  if (Major == 8 && Minor == 0)
-    return CudaVersion::CUDA_80;
-  if (Major == 9 && Minor == 0)
-    return CudaVersion::CUDA_90;
-  if (Major == 9 && Minor == 1)
-    return CudaVersion::CUDA_91;
-  if (Major == 9 && Minor == 2)
-    return CudaVersion::CUDA_92;
-  if (Major == 10 && Minor == 0)
-    return CudaVersion::CUDA_100;
-  if (Major == 10 && Minor == 1)
-    return CudaVersion::CUDA_101;
-  return CudaVersion::UNKNOWN;
+  std::string MajorMinor = join_items(".", VersionParts[0], VersionParts[1]);
+  CudaVersion Version = CudaStringToVersion(MajorMinor);
+  if (Version != CudaVersion::UNKNOWN)
+    return Version;
+
+  // Issue a warning and assume that the version we've found is compatible with
+  // the latest version we support.
+  D.Diag(diag::warn_drv_unknown_cuda_version)
+      << MajorMinor << CudaVersionToString(CudaVersion::LATEST);
+  return CudaVersion::LATEST;
 }
 
 CudaInstallationDetector::CudaInstallationDetector(
@@ -160,7 +147,7 @@ CudaInstallationDetector::CudaInstallationDetector(
       // version.txt isn't present.
       Version = CudaVersion::CUDA_70;
     } else {
-      Version = ParseCudaVersionFile((*VersionFile)->getBuffer());
+      Version = ParseCudaVersionFile(D, (*VersionFile)->getBuffer());
     }
 
     if (Version >= CudaVersion::CUDA_90) {