diff --git a/llvm/include/llvm/Support/raw_ostream.h b/llvm/include/llvm/Support/raw_ostream.h
--- a/llvm/include/llvm/Support/raw_ostream.h
+++ b/llvm/include/llvm/Support/raw_ostream.h
@@ -295,7 +295,7 @@
 
   /// This function determines if this stream is displayed and supports colors.
   /// The result is unaffected by calls to enable_color().
-  virtual bool has_colors() const { return is_displayed(); }
+  virtual bool has_colors() { return is_displayed(); }
 
   // Enable or disable colors. Once enable_colors(false) is called,
   // changeColor() has no effect until enable_colors(true) is called.
@@ -412,6 +412,7 @@
   int FD;
   bool ShouldClose;
   bool SupportsSeeking = false;
+  Optional<bool> HasColors;
 
 #ifdef _WIN32
   /// True if this fd refers to a Windows console device. Mintty and other
@@ -479,7 +480,7 @@
 
   bool is_displayed() const override;
 
-  bool has_colors() const override;
+  bool has_colors() override;
 
   std::error_code error() const { return EC; }
 
diff --git a/llvm/lib/Support/raw_ostream.cpp b/llvm/lib/Support/raw_ostream.cpp
--- a/llvm/lib/Support/raw_ostream.cpp
+++ b/llvm/lib/Support/raw_ostream.cpp
@@ -857,8 +857,10 @@
   return sys::Process::FileDescriptorIsDisplayed(FD);
 }
 
-bool raw_fd_ostream::has_colors() const {
-  return sys::Process::FileDescriptorHasColors(FD);
+bool raw_fd_ostream::has_colors() {
+  if (!HasColors)
+    HasColors = sys::Process::FileDescriptorHasColors(FD);
+  return *HasColors;
 }
 
 Expected<sys::fs::FileLocker> raw_fd_ostream::lock() {