Index: lldb/include/lldb/Utility/Log.h
===================================================================
--- lldb/include/lldb/Utility/Log.h
+++ lldb/include/lldb/Utility/Log.h
@@ -206,6 +206,11 @@
 
 } // namespace lldb_private
 
+/// The LLDB_LOG macro uses the llvm::formatv system (see the ProgrammersManual page in the
+/// llvm docs for more details).  This allows the use of "format_providers" to auto-format some of the
+/// llvm and lldb datatypes.  If you need to do non-trivial formatting of one of these types,
+/// be sure to grep the lldb and llvm sources for format_provider to see if there is already a formatter
+/// before doing in situ formatting, and feel free to add a provider if one does not exist.
 #define LLDB_LOG(log, ...)                                                     \
   do {                                                                         \
     ::lldb_private::Log *log_private = (log);                                  \