[Lldb-commits] [lldb] Convert the StackFrameList mutex to a shared mutex. (PR #117252)

[Pavel Labath via lldb-commits]

================
@@ -93,25 +94,37 @@ class StackFrameList {
                    bool show_frame_info, uint32_t num_frames_with_source,
                    bool show_unique = false, bool show_hidden = false,
                    const char *frame_marker = nullptr);
+                
+  /// Returns whether we have currently fetched all the frames of a stack.
+  bool WereAllFramesFetched() const;
 
 protected:
   friend class Thread;
   friend class ScriptedThread;
 
+  /// Use this API to build a stack frame list (used for scripted threads, for
+  /// instance.)  This API is not meant for StackFrameLists that have unwinders
+  /// and partake in lazy stack filling (using GetFramesUpTo).  Rather if you
+  /// are building StackFrameLists with this API, you should build the entire
+  /// list before making it available for use.
   bool SetFrameAtIndex(uint32_t idx, lldb::StackFrameSP &frame_sp);
 
-  /// Realizes frames up to (and including) end_idx (which can be greater than  
-  /// the actual number of frames.)  
+  /// Ensures that frames up to (and including) `end_idx` are realized in the
+  /// StackFrameList.  `end_idx` can be larger than the actual number of frames,
+  /// in which case all the frames will be fetched.  Acquires the writer end of
+  /// the list mutex.
   /// Returns true if the function was interrupted, false otherwise.
-  bool GetFramesUpTo(uint32_t end_idx, 
-      InterruptionControl allow_interrupt = AllowInterruption);
-
-  void GetOnlyConcreteFramesUpTo(uint32_t end_idx, Unwind &unwinder);
-
-  void SynthesizeTailCallFrames(StackFrame &next_frame);
-
-  bool GetAllFramesFetched() { return m_concrete_frames_fetched == UINT32_MAX; }
+  /// Callers should first check (under the shared mutex) whether we need to
+  /// fetch frames or not.
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labath wrote:

(optional) I'd consider putting the read-locked check into the function itself. I think then you wouldn't need the `WereAllFramesFetched` check in `GetNumFrames`, and I don't think it should hurt the other callers.

https://github.com/llvm/llvm-project/pull/117252