--- a/layout/generic/nsBlockFrame.cpp
+++ b/layout/generic/nsBlockFrame.cpp
@@ -4158,17 +4158,17 @@ nsBlockFrame::ReflowInlineFrame(BlockRef
   aLineLayout.ReflowFrame(aFrame, frameReflowStatus, nullptr, pushedFrame);
 
   if (frameReflowStatus.NextInFlowNeedsReflow()) {
     aLineLayout.SetDirtyNextLine();
   }
 
 #ifdef REALLY_NOISY_REFLOW
   nsFrame::ListTag(stdout, aFrame);
-  printf(": status=%x\n", frameReflowStatus);
+  printf(": status=%s\n", frameReflowStatus.ToString().get());
 #endif
 
 #if defined(REFLOW_STATUS_COVERAGE)
   RecordReflowStatus(false, frameReflowStatus);
 #endif
 
   // Send post-reflow notification
   aState.mPrevChild = aFrame;

--- a/layout/generic/nsFrame.cpp
+++ b/layout/generic/nsFrame.cpp
@@ -278,16 +278,26 @@ std::ostream& operator<<(std::ostream& a
           << "NIF=" << (aStatus.NextInFlowNeedsReflow() ? 'Y' : 'N') << ","
           << "Truncated=" << (aStatus.IsTruncated() ? 'Y' : 'N') << ","
           << "Break=" << brk << ","
           << "FirstLetter=" << (aStatus.FirstLetterComplete() ? 'Y' : 'N')
           << "]";
   return aStream;
 }
 
+nsCString
+nsReflowStatus::ToString() const
+{
+  nsCString result;
+  std::stringstream ss;
+  ss << *this;
+  result.Append(ss.str().c_str());
+  return result;
+}
+
 static bool gShowFrameBorders = false;
 
 void nsFrame::ShowFrameBorders(bool aEnable)
 {
   gShowFrameBorders = aEnable;
 }
 
 bool nsFrame::GetShowFrameBorders()

--- a/layout/generic/nsIFrame.h
+++ b/layout/generic/nsIFrame.h
@@ -351,16 +351,20 @@ public:
     mInlineBreak = InlineBreak::After;
   }
 
   // mFirstLetterComplete bit flag means the break was induced by
   // completion of a first-letter.
   bool FirstLetterComplete() const { return mFirstLetterComplete; }
   void SetFirstLetterComplete() { mFirstLetterComplete = true; }
 
+#ifdef DEBUG
+  nsCString ToString() const;
+#endif
+
 private:
   StyleClear mBreakType;
   InlineBreak mInlineBreak;
   Completion mCompletion;
   bool mNextInFlowNeedsReflow : 1;
   bool mTruncated : 1;
   bool mFirstLetterComplete : 1;
 };