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, 31 insertions, 13 deletions

diff --git a/lib/dialyzer/src/dialyzer_cl_parse.erl b/lib/dialyzer/src/dialyzer_cl_parse.erl
index 0160b84abc..2f9e577544 100644
--- a/lib/dialyzer/src/dialyzer_cl_parse.erl
+++ b/lib/dialyzer/src/dialyzer_cl_parse.erl
@@ -138,11 +138,17 @@ cl(["-pa", Path|T]) ->
     true -> cl(T);
     {error, _} -> error("Bad directory for -pa: "++Path)
   end;
-cl(["--plt", PLT|T]) ->
-  put(dialyzer_init_plt, PLT),
-  cl(T);
 cl(["--plt"]) ->
   error("No plt specified for --plt");
+cl(["--plt", PLT|T]) ->
+  put(dialyzer_init_plts, [PLT]),
+  cl(T);
+cl(["--plts"]) ->
+  error("No plts specified for --plts");
+cl(["--plts"|T]) ->
+  {PLTs, NewT} = get_plts(T, []),
+  put(dialyzer_init_plts, PLTs),
+  cl(NewT);
 cl(["-q"|T]) ->
   put(dialyzer_options_report_mode, quiet),
   cl(T);
@@ -284,7 +290,7 @@ common_options() ->
   [{defines, get(dialyzer_options_defines)},
    {from, get(dialyzer_options_from)},
    {include_dirs, get(dialyzer_include)},
-   {init_plt, get(dialyzer_init_plt)},
+   {plts, get(dialyzer_init_plts)},
    {output_plt, get(dialyzer_output_plt)},
    {report_mode, get(dialyzer_options_report_mode)},
    {use_spec, get(dialyzer_options_use_contracts)},
@@ -309,6 +315,13 @@ get_lib_dir([], Acc) ->
 
 %%-----------------------------------------------------------------------
 
+get_plts(["--"|T], Acc) -> {lists:reverse(Acc), T};
+get_plts(["-"++_Opt = H|T], Acc) -> {lists:reverse(Acc), [H|T]};
+get_plts([H|T], Acc) -> get_plts(T, [H|Acc]);
+get_plts([], Acc) -> {lists:reverse(Acc), []}.
+
+%%-----------------------------------------------------------------------
+
 help_warnings() ->
   S = warning_options_msg(),
   io:put_chars(S),
@@ -316,9 +329,10 @@ help_warnings() ->
 
 help_message() ->
   S = "Usage: dialyzer [--help] [--version] [--shell] [--quiet] [--verbose]
-		[-pa dir]* [--plt plt] [-Ddefine]* [-I include_dir]* 
-		[--output_plt file] [-Wwarn]* [--src] [--gui | --wx]
-		[files_or_dirs] [-r dirs] [--apps applications] [-o outfile]
+		[-pa dir]* [--plt plt] [--plts plts] [-Ddefine]*
+                [-I include_dir]* [--output_plt file] [-Wwarn]*
+                [--src] [--gui | --wx] [files_or_dirs] [-r dirs]
+                [--apps applications] [-o outfile]
 		[--build_plt] [--add_to_plt] [--remove_from_plt]
 		[--check_plt] [--no_check_plt] [--plt_info] [--get_warnings]
                 [--no_native]
@@ -362,6 +376,10 @@ Options:
   --plt plt
       Use the specified plt as the initial plt (if the plt was built 
       during setup the files will be checked for consistency)
+  --plts plts
+      Merges the specified plts to create the initial plt -- requires
+      that the plts are disjoint (i.e., do not have any module
+      appearing in more than one plt)
   -Wwarn
       A family of options which selectively turn on/off warnings
       (for help on the names of warnings use dialyzer -Whelp)
@@ -378,12 +396,12 @@ Options:
   --build_plt
       The analysis starts from an empty plt and creates a new one from the
       files specified with -c and -r. Only works for beam files.
-      Use --plt or --output_plt to override the default plt location.
+      Use --plt(s) or --output_plt to override the default plt location.
   --add_to_plt
       The plt is extended to also include the files specified with -c and -r.
-      Use --plt to specify wich plt to start from, and --output_plt to 
-      specify where to put the plt. Note that the analysis might include 
-      files from the plt if they depend on the new files. 
+      Use --plt(s) to specify wich plt to start from, and --output_plt to
+      specify where to put the plt. Note that the analysis might include
+      files from the plt if they depend on the new files.
       This option only works with beam files.
   --remove_from_plt
       The information from the files specified with -c and -r is removed
@@ -396,8 +414,8 @@ Options:
       Skip the plt check when running Dialyzer. Useful when working with
       installed plts that never change.
   --plt_info
-      Makes Dialyzer print information about the plt and then quit. The plt 
-      can be specified with --plt.
+      Makes Dialyzer print information about the plt and then quit. The plt
+      can be specified with --plt(s).
   --get_warnings
       Makes Dialyzer emit warnings even when manipulating the plt. Only 
       emits warnings for files that are actually analyzed.