dialyzer: Add support for multiple PLTs

This new feature is able to take multiple PLTs, merge them during the
start of the analysis, and work from there. This works provided that
the PLTs do not have a module with the same name appearing in more
than one PLT.

The PLTs are created in the usual way:

    dialyzer --build_plt --output_plt PLT_1  FILES_TO_INCLUDE
    ...
    dialyzer --build_plt --output_plt PLT_N  FILES_TO_INCLUDE

and then can be used in either of the following ways:

    dialyzer  FILES_TO_ANALYZE  --plts PLT_1 ... PLT_N
or:
    dialyzer --plts PLT_1 ... PLT_N -- FILES_TO_ANALYZE

(Note the -- delimiter in the second case)

1 files changed, 80 insertions, 40 deletions

diff --git a/lib/dialyzer/src/dialyzer_cl.erl b/lib/dialyzer/src/dialyzer_cl.erl
index 0250c47ad0..1987c1732c 100644
--- a/lib/dialyzer/src/dialyzer_cl.erl
+++ b/lib/dialyzer/src/dialyzer_cl.erl
@@ -81,11 +81,15 @@ build_plt(Opts) ->
 init_opts_for_build(Opts) ->
   case Opts#options.output_plt =:= none of
     true ->
-      case Opts#options.init_plt of
-	none -> Opts#options{init_plt = none, output_plt = get_default_plt()};
-	Plt  -> Opts#options{init_plt = none, output_plt = Plt}
+      case Opts#options.init_plts of
+	[] -> Opts#options{output_plt = get_default_output_plt()};
+	[Plt] -> Opts#options{init_plts = [], output_plt = Plt};
+        Plts ->
+          Msg = io_lib:format("Could not build multiple PLT files: ~s\n",
+                              [format_plts(Plts)]),
+          error(Msg)
       end;
-    false -> Opts#options{init_plt = none}
+    false -> Opts#options{init_plts = []}
   end.
 
 %%--------------------------------------------------------------------
@@ -98,39 +102,58 @@ add_to_plt(Opts) ->
 init_opts_for_add(Opts) ->
   case Opts#options.output_plt =:= none of
     true ->
-      case Opts#options.init_plt of
-	none -> Opts#options{output_plt = get_default_plt(),
-			     init_plt = get_default_plt()};
-	Plt  -> Opts#options{output_plt = Plt}
+      case Opts#options.init_plts of
+	[] -> Opts#options{output_plt = get_default_output_plt(),
+                           init_plts = get_default_init_plt()};
+	[Plt] -> Opts#options{output_plt = Plt};
+        Plts ->
+          Msg = io_lib:format("Could not add to multiple PLT files: ~s\n",
+                              [format_plts(Plts)]),
+          error(Msg)
       end;
     false ->
-      case Opts#options.init_plt =:= none of
-	true  -> Opts#options{init_plt = get_default_plt()};
+      case Opts#options.init_plts =:= [] of
+	true  -> Opts#options{init_plts = get_default_init_plt()};
 	false -> Opts
       end
   end.
 
 %%--------------------------------------------------------------------
 
-check_plt(Opts) ->
+check_plt(#options{init_plts = []} = Opts) ->
   Opts1 = init_opts_for_check(Opts),
-  report_check(Opts),
-  plt_common(Opts1, [], []).
+  report_check(Opts1),
+  plt_common(Opts1, [], []);
+check_plt(#options{init_plts = Plts} = Opts) ->
+  check_plt_aux(Plts, Opts).
+
+check_plt_aux([_] = Plt, Opts) ->
+  Opts1 = Opts#options{init_plts = Plt},
+  Opts2 = init_opts_for_check(Opts1),
+  report_check(Opts2),
+  plt_common(Opts2, [], []);
+check_plt_aux([Plt|Plts], Opts) ->
+  Opts1 = Opts#options{init_plts = [Plt]},
+  Opts2 = init_opts_for_check(Opts1),
+  report_check(Opts2),
+  plt_common(Opts2, [], []),
+  check_plt_aux(Plts, Opts).
 
 init_opts_for_check(Opts) ->
-  Plt =
-    case Opts#options.init_plt of
-      none -> get_default_plt();
-      Plt0 -> Plt0
+  InitPlt =
+    case Opts#options.init_plts of
+      []-> get_default_init_plt();
+      Plt -> Plt
     end,
+  [OutputPlt] = InitPlt,
   Opts#options{files         = [],
 	       files_rec     = [],
 	       analysis_type = plt_check,
 	       defines       = [],
 	       from          = byte_code,
-	       init_plt      = Plt,
+	       init_plts     = InitPlt,
 	       include_dirs  = [],
-	       output_plt    = Plt,
+	       output_plt    = OutputPlt,
 	       use_contracts = true
 	      }.
 
@@ -144,21 +167,25 @@ remove_from_plt(Opts) ->
 init_opts_for_remove(Opts) ->
   case Opts#options.output_plt =:= none of
     true ->
-      case Opts#options.init_plt of
-	none -> Opts#options{output_plt = get_default_plt(),
-			     init_plt = get_default_plt()};
-	Plt  -> Opts#options{output_plt = Plt}
+      case Opts#options.init_plts of
+	[] -> Opts#options{output_plt = get_default_output_plt(),
+                           init_plts = get_default_init_plt()};
+	[Plt] -> Opts#options{output_plt = Plt};
+        Plts ->
+          Msg = io_lib:format("Could not remove from multiple PLT files: ~s\n",
+                              [format_plts(Plts)]),
+          error(Msg)
       end;
     false ->
-      case Opts#options.init_plt =:= none of
-	true  -> Opts#options{init_plt = get_default_plt()};
+      case Opts#options.init_plts =:= [] of
+	true  -> Opts#options{init_plts = get_default_init_plt()};
 	false -> Opts
       end
   end.
 
 %%--------------------------------------------------------------------
 
-plt_common(Opts, RemoveFiles, AddFiles) ->
+plt_common(#options{init_plts = [InitPlt]} = Opts, RemoveFiles, AddFiles) ->
   case check_plt(Opts, RemoveFiles, AddFiles) of
     ok ->
       case Opts#options.report_mode of
@@ -174,7 +201,7 @@ plt_common(Opts, RemoveFiles, AddFiles) ->
       report_failed_plt_check(Opts, DiffMd5),
       {AnalFiles, RemovedMods, ModDeps1} = 
 	expand_dependent_modules(Md5, DiffMd5, ModDeps),
-      Plt = clean_plt(Opts#options.init_plt, RemovedMods),
+      Plt = clean_plt(InitPlt, RemovedMods),
       case AnalFiles =:= [] of
 	true ->
 	  %% Only removed stuff. Just write the PLT.
@@ -186,19 +213,19 @@ plt_common(Opts, RemoveFiles, AddFiles) ->
       end;
     {error, no_such_file} ->
       Msg = io_lib:format("Could not find the PLT: ~s\n~s",
-			  [Opts#options.init_plt, default_plt_error_msg()]),
+			  [InitPlt, default_plt_error_msg()]),
       error(Msg);
     {error, not_valid} ->
       Msg = io_lib:format("The file: ~s is not a valid PLT file\n~s",
-			  [Opts#options.init_plt, default_plt_error_msg()]),
+			  [InitPlt, default_plt_error_msg()]),
       error(Msg);
     {error, read_error} ->
       Msg = io_lib:format("Could not read the PLT: ~s\n~s",
-			  [Opts#options.init_plt, default_plt_error_msg()]),
+			  [InitPlt, default_plt_error_msg()]),
       error(Msg);
     {error, {no_file_to_remove, F}} ->
       Msg = io_lib:format("Could not remove the file ~s from the PLT: ~s\n",
-			  [F, Opts#options.init_plt]),
+			  [F, InitPlt]),
       error(Msg)
   end.
 
@@ -218,8 +245,7 @@ default_plt_error_msg() ->
 
 %%--------------------------------------------------------------------
 
-check_plt(Opts, RemoveFiles, AddFiles) ->
-  Plt = Opts#options.init_plt,
+check_plt(#options{init_plts = [Plt]} = Opts, RemoveFiles, AddFiles) ->
   case dialyzer_plt:check_plt(Plt, RemoveFiles, AddFiles) of
     {old_version, _MD5} = OldVersion ->
       report_old_version(Opts),
@@ -234,14 +260,14 @@ check_plt(Opts, RemoveFiles, AddFiles) ->
 
 %%--------------------------------------------------------------------
 
-report_check(#options{report_mode = ReportMode, init_plt = InitPlt}) ->
+report_check(#options{report_mode = ReportMode, init_plts = [InitPlt]}) ->
   case ReportMode of
     quiet -> ok;
     _ ->
       io:format("  Checking whether the PLT ~s is up-to-date...", [InitPlt])
   end.
 
-report_old_version(#options{report_mode = ReportMode, init_plt = InitPlt}) ->
+report_old_version(#options{report_mode = ReportMode, init_plts = [InitPlt]}) ->
   case ReportMode of
     quiet -> ok;
     _ ->
@@ -264,7 +290,7 @@ report_failed_plt_check(#options{analysis_type = AnalType,
 
 report_analysis_start(#options{analysis_type = Type,
 			       report_mode = ReportMode,
-			       init_plt = InitPlt, 
+			       init_plts = InitPlts,
 			       output_plt = OutputPlt}) ->
   case ReportMode of
     quiet -> ok;
@@ -272,6 +298,7 @@ report_analysis_start(#options{analysis_type = Type,
       io:format("  "),
       case Type of
 	plt_add ->
+          [InitPlt] = InitPlts,
 	  case InitPlt =:= OutputPlt of
 	    true -> io:format("Adding information to ~s...", [OutputPlt]);
 	    false -> io:format("Adding information from ~s to ~s...", 
@@ -282,6 +309,7 @@ report_analysis_start(#options{analysis_type = Type,
 	plt_check ->
 	  io:format("Rebuilding the information in ~s...", [OutputPlt]);
 	plt_remove ->
+          [InitPlt] = InitPlts,
 	  case InitPlt =:= OutputPlt of
 	    true -> io:format("Removing information from ~s...", [OutputPlt]);
 	    false -> io:format("Removing information from ~s to ~s...", 
@@ -320,16 +348,28 @@ report_md5_diff(List) ->
 
 %%--------------------------------------------------------------------
 
-get_default_plt() ->
+get_default_init_plt() ->
+  [dialyzer_plt:get_default_plt()].
+
+get_default_output_plt() ->
   dialyzer_plt:get_default_plt().
 
 %%--------------------------------------------------------------------
 
+format_plts([Plt]) -> Plt;
+format_plts([Plt|Plts]) ->
+  Plt ++ ", " ++ format_plts(Plts).
+
+%%--------------------------------------------------------------------
+
 do_analysis(Options) ->
   Files = get_files_from_opts(Options),
-  case Options#options.init_plt of
-    none -> do_analysis(Files, Options, dialyzer_plt:new(), none);
-    File -> do_analysis(Files, Options, dialyzer_plt:from_file(File), none)
+  case Options#options.init_plts of
+    [] -> do_analysis(Files, Options, dialyzer_plt:new(), none);
+    PltFiles ->
+      Plts = [dialyzer_plt:from_file(F) || F <- PltFiles],
+      Plt = dialyzer_plt:merge_plts_or_report_conflicts(PltFiles, Plts),
+      do_analysis(Files, Options, Plt, none)
   end.
   
 do_analysis(Files, Options, Plt, PltInfo) ->