3 files changed, 24 insertions, 0 deletions
diff --git a/llvm/include/llvm/Support/FileSystem.h b/llvm/include/llvm/Support/FileSystem.h
index 6de8759dda2..21159dd2642 100644
--- a/llvm/include/llvm/Support/FileSystem.h
+++ b/llvm/include/llvm/Support/FileSystem.h
@@ -356,6 +356,12 @@ inline bool exists(const Twine &path) {
 /// @returns True if we can execute it, false otherwise.
 bool can_execute(const Twine &Path);
 
+/// @brief Can we write this file?
+///
+/// @param Path Input path.
+/// @returns True if we can write to it, false otherwise.
+bool can_write(const Twine &Path);
+
 /// @brief Do file_status's represent the same thing?
 ///
 /// @param A Input file_status.
diff --git a/llvm/lib/Support/Unix/PathV2.inc b/llvm/lib/Support/Unix/PathV2.inc
index 9ea4f9ed51a..a806083b193 100644
--- a/llvm/lib/Support/Unix/PathV2.inc
+++ b/llvm/lib/Support/Unix/PathV2.inc
@@ -308,6 +308,12 @@ error_code exists(const Twine &path, bool &result) {
   return error_code::success();
 }
 
+bool can_write(const Twine &Path) {
+  SmallString<128> PathStorage;
+  StringRef P = Path.toNullTerminatedStringRef(PathStorage);
+  return 0 == access(P.begin(), W_OK);
+}
+
 bool can_execute(const Twine &Path) {
   SmallString<128> PathStorage;
   StringRef P = Path.toNullTerminatedStringRef(PathStorage);
diff --git a/llvm/lib/Support/Windows/PathV2.inc b/llvm/lib/Support/Windows/PathV2.inc
index 3b2992d5a30..bec95e36cc5 100644
--- a/llvm/lib/Support/Windows/PathV2.inc
+++ b/llvm/lib/Support/Windows/PathV2.inc
@@ -362,6 +362,18 @@ error_code exists(const Twine &path, bool &result) {
   return error_code::success();
 }
 
+bool can_write(const Twine &Path) {
+  // FIXME: take security attributes into account.
+  SmallString<128> PathStorage;
+  SmallVector<wchar_t, 128> PathUtf16;
+
+  if (UTF8ToUTF16(Path.toStringRef(PathStorage), PathUtf16))
+    return false;
+
+  DWORD Attr = ::GetFileAttributesW(PathUtf16.begin());
+  return (Attr != INVALID_FILE_ATTRIBUTES) && !(Attr & FILE_ATTRIBUTE_READONLY);
+}
+
 bool can_execute(const Twine &Path) {
   SmallString<128> PathStorage;
   SmallVector<wchar_t, 128> PathUtf16;