Merge branch 'bg/beam_lib' into dev

* bg/beam_lib:
  Remove redundant includes
  Make beam_lib:cmp/2 stricter

OTP-8625 bg/beam_lib

The beam_lib:cmp/2 function now compares BEAM files in stricter way. The
BEAM files will be considered different if there are any changes except in
the compilation information ("CInf") chunk. beam_lib:cmp/2 used to ignore
differences in the debug information (significant for Dialyzer) and other
chunks that did not directly change the run-time behavior.

2 files changed, 26 insertions, 16 deletions

diff --git a/lib/stdlib/doc/src/beam_lib.xml b/lib/stdlib/doc/src/beam_lib.xml
index b9286f1402..27308e02f3 100644
--- a/lib/stdlib/doc/src/beam_lib.xml
+++ b/lib/stdlib/doc/src/beam_lib.xml
@@ -347,9 +347,10 @@ chunkref() = chunkname() | chunkid()</code>
       </type>
       <desc>
         <p>Compares the contents of two BEAM files. If the module names
-          are the same, and the chunks with the identifiers
-          <c>"Code"</c>, <c>"ExpT"</c>, <c>"ImpT"</c>, <c>"StrT"</c>,
-          and <c>"Atom"</c> have the same contents in both files,
+          are the same, and all chunks except for the <c>"CInf"</c> chunk
+	  (the chunk containing the compilation information which is
+	  returned by <c>Module:module_info(compile)</c>)
+	  have the same contents in both files,
           <c>ok</c> is returned. Otherwise an error message is returned.</p>
       </desc>
     </func>
diff --git a/lib/stdlib/src/beam_lib.erl b/lib/stdlib/src/beam_lib.erl
index 820afd3739..c71dad6163 100644
--- a/lib/stdlib/src/beam_lib.erl
+++ b/lib/stdlib/src/beam_lib.erl
@@ -1,19 +1,19 @@
 %%
 %% %CopyrightBegin%
-%% 
-%% Copyright Ericsson AB 2000-2009. All Rights Reserved.
-%% 
+%%
+%% Copyright Ericsson AB 2000-2010. All Rights Reserved.
+%%
 %% The contents of this file are subject to the Erlang Public License,
 %% Version 1.1, (the "License"); you may not use this file except in
 %% compliance with the License. You should have received a copy of the
 %% Erlang Public License along with this software. If not, it can be
 %% retrieved online at http://www.erlang.org/.
-%% 
+%%
 %% Software distributed under the License is distributed on an "AS IS"
 %% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 %% the License for the specific language governing rights and limitations
 %% under the License.
-%% 
+%%
 %% %CopyrightEnd%
 %%
 -module(beam_lib).
@@ -44,9 +44,6 @@
 -import(lists, [append/1, delete/2, foreach/2, keysort/2, 
 		member/2, reverse/1, sort/1, splitwith/2]).
 
--include_lib("kernel/include/file.hrl").
--include("erl_compile.hrl").
-
 %%-------------------------------------------------------------------------
 
 -type beam() :: module() | file:filename() | binary().
@@ -331,13 +328,11 @@ beam_files(Dir) ->
 
 %% -> ok | throw(Error)
 cmp_files(File1, File2) ->
-    {ok, {M1, L1}} = read_significant_chunks(File1),
-    {ok, {M2, L2}} = read_significant_chunks(File2),
+    {ok, {M1, L1}} = read_all_but_useless_chunks(File1),
+    {ok, {M2, L2}} = read_all_but_useless_chunks(File2),
     if
 	M1 =:= M2 ->
-	    List1 = filter_funtab(L1),
-	    List2 = filter_funtab(L2),
-	    cmp_lists(List1, List2);
+	    cmp_lists(L1, L2);
 	true ->
 	    error({modules_different, M1, M2})
     end.
@@ -408,6 +403,20 @@ pad(Size) ->
     end.
 
 %% -> {ok, {Module, Chunks}} | throw(Error)
+read_all_but_useless_chunks(File0) when is_atom(File0);
+					is_list(File0);
+					is_binary(File0) ->
+    File = beam_filename(File0),
+    {ok, Module, ChunkIds0} = scan_beam(File, info),
+    ChunkIds = [Name || {Name,_,_} <- ChunkIds0,
+			not is_useless_chunk(Name)],
+    {ok, Module, Chunks} = scan_beam(File, ChunkIds),
+    {ok, {Module, lists:reverse(Chunks)}}.
+
+is_useless_chunk("CInf") -> true;
+is_useless_chunk(_) -> false.
+
+%% -> {ok, {Module, Chunks}} | throw(Error)
 read_significant_chunks(File) ->
     case read_chunk_data(File, significant_chunks(), [allow_missing_chunks]) of
 	{ok, {Module, Chunks0}} ->