[clang] bff2aa6 - [clang] Ensure `--print-runtime-dir` path exists (#102834)

[via cfe-commits]

Author: Alexandre Ganea
Date: 2025-11-01T16:54:46Z
New Revision: bff2aa63624766b1111be0ffec9645c952fc8e38

URL: https://github.com/llvm/llvm-project/commit/bff2aa63624766b1111be0ffec9645c952fc8e38
DIFF: https://github.com/llvm/llvm-project/commit/bff2aa63624766b1111be0ffec9645c952fc8e38.diff

LOG: [clang] Ensure `--print-runtime-dir` path exists (#102834)

Before this PR, `clang --print-runtime-dir` on Windows used to report a
non-existent directory if `LLVM_ENABLE_PER_TARGET_RUNTIME_DIR=OFF`.

We now check if any of the known runtime directories exist before
printing any of them on stdout. If none exists, we print `(runtime dir
is not present)`.

Added: 
    

Modified: 
    clang/lib/Driver/Driver.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index 71c52807091ba..51618d17a4180 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -2540,10 +2540,14 @@ bool Driver::HandleImmediateArgs(Compilation &C) {
   }
 
   if (C.getArgs().hasArg(options::OPT_print_runtime_dir)) {
-    if (std::optional<std::string> RuntimePath = TC.getRuntimePath())
-      llvm::outs() << *RuntimePath << '\n';
-    else
-      llvm::outs() << TC.getCompilerRTPath() << '\n';
+    for (auto RuntimePath :
+         {TC.getRuntimePath(), std::make_optional(TC.getCompilerRTPath())}) {
+      if (RuntimePath && getVFS().exists(*RuntimePath)) {
+        llvm::outs() << *RuntimePath << '\n';
+        return false;
+      }
+    }
+    llvm::outs() << "(runtime dir is not present)" << '\n';
     return false;
   }