PathV2: Fix a possible infinite loop.

 - The code could infinite loop trying to create unique files, if the directory
   containing the unique file exists, but open() calls on non-existent files in
   the path return ENOENT. This is true on the /dev/fd filesystem, for example.

 - Will add a clang side test case for this.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168081 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Support/Unix/PathV2.inc b/lib/Support/Unix/PathV2.inc
index d04f590f87ed10fa6c265b12cd3393f6c2d13bd1..05fd924960e10855ba4254081894c23d6a33ee5f 100644 (file)
--- a/lib/Support/Unix/PathV2.inc
+++ b/lib/Support/Unix/PathV2.inc
@@ -424,9 +424,10 @@ rety_open_create:
     // If the file existed, try again, otherwise, error.
     if (errno == errc::file_exists)
       goto retry_random_path;
-    // The path prefix doesn't exist.
-    if (errno == errc::no_such_file_or_directory) {
-      StringRef p(RandomPath.begin(), RandomPath.size());
+    // If path prefix doesn't exist, try to create it.
+    if (errno == errc::no_such_file_or_directory &&
+        !exists(path::parent_path(RandomPath))) {
+      StringRef p(RandomPath);
       SmallString<64> dir_to_create;
       for (path::const_iterator i = path::begin(p),
                                 e = --path::end(p); i != e; ++i) {