[lldb] Change lldb's breakpoint handling behavior

lldb/include/lldb/Target/Thread.h

@@ -129,6 +129,7 @@ class Thread : public std::enable_shared_from_this<Thread>,
         register_backup_sp; // You need to restore the registers, of course...
     uint32_t current_inlined_depth;
     lldb::addr_t current_inlined_pc;
+    lldb::addr_t stopped_at_unexecuted_bp;
   };
 
   /// Constructor
@@ -378,6 +379,26 @@ class Thread : public std::enable_shared_from_this<Thread>,
 
   virtual void SetQueueLibdispatchQueueAddress(lldb::addr_t dispatch_queue_t) {}
 
+  /// When a thread stops at an enabled BreakpointSite that has not executed,
+  /// the Process plugin should call SetThreadStoppedAtUnexecutedBP(pc).
+  /// If that BreakpointSite was actually triggered (the instruction was
+  /// executed, for a software breakpoint), regardless of whether the
+  /// breakpoint is valid for this thread, SetThreadHitBreakpointSite()
+  /// should be called to record that fact.
+  ///
+  /// Depending on the structure of the Process plugin, it may be easiest
+  /// to call SetThreadStoppedAtUnexecutedBP(pc) unconditionally when at
+  /// a BreakpointSite, and later when it is known that it was triggered,
+  /// SetThreadHitBreakpointSite() can be called.  These two methods
+  /// overwrite the same piece of state in the Thread, the last one
+  /// called on a Thread wins.
+  void SetThreadStoppedAtUnexecutedBP(lldb::addr_t pc) {
+    m_stopped_at_unexecuted_bp = pc;
+  }
+  void SetThreadHitBreakpointSite() {
+    m_stopped_at_unexecuted_bp = LLDB_INVALID_ADDRESS;
+  }
+
   /// Whether this Thread already has all the Queue information cached or not
   ///
   /// A Thread may be associated with a libdispatch work Queue at a given
@@ -1312,6 +1333,9 @@ class Thread : public std::enable_shared_from_this<Thread>,
   bool m_should_run_before_public_stop;  // If this thread has "stop others" 
                                          // private work to do, then it will
                                          // set this.
+  lldb::addr_t m_stopped_at_unexecuted_bp; // Set to the address of a breakpoint
+                                           // instruction that we have not yet
+                                           // hit, but will hit when we resume.
   const uint32_t m_index_id; ///< A unique 1 based index assigned to each thread
                              /// for easy UI/command line access.
   lldb::RegisterContextSP m_reg_context_sp; ///< The register context for this