[DebugInfo][NFC] Add a comment on the ordering of DILineInfo frames.

[snehasish]

Summary

Add a comment to getFrame() to mention that frames are stored in
bottom-up, i.e. leaf to root in order of increasing index.

[dblaikie]

Sure, sounds OK!

[tejohnson]

llvm/include/llvm/DebugInfo/DIContext.h

94

Nit, missing comma after "leaf-to-root" to match prior comma. Or remove prior comma and put "i.e. leaf-to-root" in parentheses.

[tejohnson]

(but lgtm otherwise)

[snehasish]

Update comment.

llvm/include/llvm/DebugInfo/DIContext.h

 
 /// A format-neutral container for inlined code description.
 class DIInliningInfo {
   SmallVector<DILineInfo, 4> Frames;
 
 public:
   DIInliningInfo() = default;
 
+  /// Returns the frame at `Index`. Frames are stored in bottom-up
+  /// (leaf-to-root) order with increasing index.
   const DILineInfo &getFrame(unsigned Index) const {
     assert(Index < Frames.size());
     return Frames[Index];
   }
 
   DILineInfo *getMutableFrame(unsigned Index) {
     assert(Index < Frames.size());
     return &Frames[Index];