Make FileOutputBuffer fail early if you pass a directory.

Previously, it created a temporary directory and then failed when
FileOutputBuffer tried to rename that file to the destination file
(which is actually a directory name).

Differential Revision: https://reviews.llvm.org/D30912

llvm-svn: 297679

2 files changed, 5 insertions, 0 deletions

diff --git a/lld/test/ELF/early-exit-for-bad-paths.s b/lld/test/ELF/early-exit-for-bad-paths.s
index aa737342bf9..856d48ba21e 100644
--- a/lld/test/ELF/early-exit-for-bad-paths.s
+++ b/lld/test/ELF/early-exit-for-bad-paths.s
@@ -20,6 +20,9 @@
 # discovered we haven't bailed out early as expected.
 # CHECK-NOT: undefined_symbol
 
+# RUN: not ld.lld %t.o -o / 2>&1 | FileCheck %s -check-prefixes=ROOT
+# ROOT: error: cannot open output file /
+
   .globl _start
 _start:
   call undefined_symbol
diff --git a/llvm/lib/Support/FileOutputBuffer.cpp b/llvm/lib/Support/FileOutputBuffer.cpp
index 57e5a8d7871..731740d012d 100644
--- a/llvm/lib/Support/FileOutputBuffer.cpp
+++ b/llvm/lib/Support/FileOutputBuffer.cpp
@@ -57,6 +57,8 @@ FileOutputBuffer::create(StringRef FilePath, size_t Size, unsigned Flags) {
         // FIXME: In posix, you use the access() call to check this.
       }
       break;
+    case sys::fs::file_type::directory_file:
+      return errc::is_a_directory;
     default:
       if (EC)
         return EC;