From 66144dba0c398c4fd2e21581b7264e861e872701 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Tue, 8 Mar 2011 07:19:47 +0100
Subject: beam_lib: Retain the "Line" chunk when stripping BEAM files

---
 lib/stdlib/src/beam_lib.erl        | 19 +++++++++++--------
 lib/stdlib/test/beam_lib_SUITE.erl | 21 ++++++++++++++++++++-
 2 files changed, 31 insertions(+), 9 deletions(-)

diff --git a/lib/stdlib/src/beam_lib.erl b/lib/stdlib/src/beam_lib.erl
index d9c645d787..9077e59fdc 100644
--- a/lib/stdlib/src/beam_lib.erl
+++ b/lib/stdlib/src/beam_lib.erl
@@ -224,7 +224,7 @@ version(File) ->
       MD5 :: binary().
 
 md5(File) ->
-    case catch read_significant_chunks(File) of
+    case catch read_significant_chunks(File, md5_chunks()) of
 	{ok, {Module, Chunks0}} ->
 	    Chunks = filter_funtab(Chunks0),
 	    {ok, {Module, erlang:md5([C || {_Id, C} <- Chunks])}};
@@ -395,7 +395,7 @@ strip_fils(Files) ->
 
 %% -> {ok, {Mod, FileName}} | {ok, {Mod, binary()}} | throw(Error)
 strip_file(File) ->
-    {ok, {Mod, Chunks}} = read_significant_chunks(File),
+    {ok, {Mod, Chunks}} = read_significant_chunks(File, significant_chunks()),
     {ok, Stripped0} = build_module(Chunks),
     Stripped = compress(Stripped0),
     case File of
@@ -453,8 +453,8 @@ 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
+read_significant_chunks(File, ChunkList) ->
+    case read_chunk_data(File, ChunkList, [allow_missing_chunks]) of
 	{ok, {Module, Chunks0}} ->
 	    Mandatory = mandatory_chunks(),
 	    Chunks = filter_significant_chunks(Chunks0, Mandatory, File, Module),
@@ -835,12 +835,15 @@ file_error(FileName, {error, Reason}) ->
 error(Reason) ->
     throw({error, ?MODULE, Reason}).
 
-
-%% The following chunks are significant when calculating the MD5 for a module,
-%% and also the modules that must be retained when stripping a file.
-%% They are listed in the order that they should be MD5:ed.
+%% The following chunks must be kept when stripping a BEAM file.
 
 significant_chunks() ->
+    ["Line" | md5_chunks()].
+
+%% The following chunks are significant when calculating the MD5
+%% for a module. They are listed in the order that they should be MD5:ed.
+
+md5_chunks() ->
     ["Atom", "Code", "StrT", "ImpT", "ExpT", "FunT", "LitT"].
 
 %% The following chunks are mandatory in every Beam file.
diff --git a/lib/stdlib/test/beam_lib_SUITE.erl b/lib/stdlib/test/beam_lib_SUITE.erl
index 4ccc863795..e42dd341c0 100644
--- a/lib/stdlib/test/beam_lib_SUITE.erl
+++ b/lib/stdlib/test/beam_lib_SUITE.erl
@@ -330,6 +330,7 @@ strip(Conf) when is_list(Conf) ->
     ?line {Source2D1, BeamFile2D1} = make_beam(PrivDir, simple2, concat),
     ?line {Source3D1, BeamFile3D1} = make_beam(PrivDir, make_fun, make_fun),
     ?line {Source4D1, BeamFile4D1} = make_beam(PrivDir, constant, constant),
+    ?line {Source5D1, BeamFile5D1} = make_beam(PrivDir, lines, lines),
 
     ?line NoOfTables = length(ets:all()),
     ?line P0 = pps(),
@@ -360,13 +361,25 @@ strip(Conf) when is_list(Conf) ->
     ?line {module, make_fun} = code:load_abs(filename:rootname(BeamFile3D1)),
     ?line {module, constant} = code:load_abs(filename:rootname(BeamFile4D1)),
 
+    %% check that line number information is still present after stripping
+    ?line {module, lines} = code:load_abs(filename:rootname(BeamFile5D1)),
+    ?line {'EXIT',{badarith,[{lines,t,1,Info}|_]}} =
+	(catch lines:t(atom)),
+    ?line true = code:delete(lines),
+    ?line false = code:purge(lines),
+    ?line {ok, {lines,BeamFile5D1}} = beam_lib:strip(BeamFile5D1),
+    ?line {module, lines} = code:load_abs(filename:rootname(BeamFile5D1)),
+    ?line {'EXIT',{badarith,[{lines,t,1,Info}|_]}} =
+	(catch lines:t(atom)),
+
     ?line true = (P0 == pps()),
     ?line NoOfTables = length(ets:all()),
 
     ?line delete_files([SourceD1, BeamFileD1, 
 			Source2D1, BeamFile2D1, 
 			Source3D1, BeamFile3D1,
-			Source4D1, BeamFile4D1]),
+			Source4D1, BeamFile4D1,
+			Source5D1, BeamFile5D1]),
     ok.
 
 
@@ -773,6 +786,12 @@ simple_file(File, Module, constant2) ->
 			"t(A) -> "
 			"    {a,b,[2,3],x,y}. "]),
     ok = file:write_file(File, B);
+simple_file(File, Module, lines) ->
+    B = list_to_binary(["-module(", atom_to_list(Module), ").\n"
+			"-export([t/1]).\n"
+			"t(A) ->\n"
+			"    A+1.\n"]),
+    ok = file:write_file(File, B);
 simple_file(File, Module, F) ->
     B = list_to_binary(["-module(", atom_to_list(Module), "). "
 			"-export([t/0]). "
-- 
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