clang-cl: Avoid confusing diagnostics when clang-cl is called just cl.exe

llvm-svn: 189901

1 files changed, 8 insertions, 1 deletions

diff --git a/clang/tools/driver/driver.cpp b/clang/tools/driver/driver.cpp
index 88863ab0661..15936bf219f 100644
--- a/clang/tools/driver/driver.cpp
+++ b/clang/tools/driver/driver.cpp
@@ -346,7 +346,14 @@ int main(int argc_, const char **argv_) {
   // DiagnosticOptions instance.
   TextDiagnosticPrinter *DiagClient
     = new TextDiagnosticPrinter(llvm::errs(), &*DiagOpts);
-  DiagClient->setPrefix(llvm::sys::path::filename(Path));
+
+  // If the clang binary happens to be named cl.exe for compatibility reasons,
+  // use clang-cl.exe as the prefix to avoid confusion between clang and MSVC.
+  StringRef ExeBasename(llvm::sys::path::filename(Path));
+  if (ExeBasename.trim().equals_lower("cl.exe"))
+    ExeBasename = "clang-cl.exe";
+  DiagClient->setPrefix(ExeBasename);
+
   IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
 
   DiagnosticsEngine Diags(DiagID, &*DiagOpts, DiagClient);