diff --git a/gcc/ada/ChangeLog b/gcc/ada/ChangeLog
index 7b909f81f8ad97be908f92f4ece00a7766faaf68..3340a4e69970d831486bd268615ea070bb676281 100644
--- a/gcc/ada/ChangeLog
+++ b/gcc/ada/ChangeLog
@@ -1,3 +1,7 @@
+2010-06-01  Arnaud Charlet  <charlet@adacore.com>
+
+	* gnat_ugn.texi: Improve doc on -fdump-ada-spec, mention limitations.
+
 2010-05-30  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* gcc-interface/decl.c (gnat_to_gnu_entity) <E_Task_Type>: Reuse the
diff --git a/gcc/ada/gnat_ugn.texi b/gcc/ada/gnat_ugn.texi
index ab52d637c95760857c4c678536bcbd2147684f71..db8b2ccd1c1b92fd6fad44ed80efff5f78751b12 100644
--- a/gcc/ada/gnat_ugn.texi
+++ b/gcc/ada/gnat_ugn.texi
@@ -23326,10 +23326,23 @@ Verbose mode: generate version information.
 @findex binding
 
 @noindent
-GNAT now comes with a new experimental binding generator for C and C++
-headers which is intended to do 95% of the tedious work of generating
-Ada specs from C or C++ header files. Note that this still is a work in
-progress, not designed to generate 100% correct Ada specs.
+GNAT now comes with a binding generator for C and C++ headers which is
+intended to do 95% of the tedious work of generating Ada specs from C
+or C++ header files.
+
+Note that this capability is not intended to generate 100% correct Ada specs,
+and will is some cases require manual adjustments, although it can often
+be used out of the box in practice.
+
+Some of the known limitations include:
+
+@itemize @bullet
+@item only very simple character constant macros are translated into Ada
+constants. Function macros (macros with arguments) are partially translated
+as comments, to be completed manually if needed.
+@item some extensions (e.g. vector types) are not supported
+@item pointers to pointers or complex structures are mapped to System.Address
+@end itemize
 
 The code generated is using the Ada 2005 syntax, which makes it
 easier to interface with other languages than previous versions of Ada.