Add dependencies Makefile generation to erlc(1) and compile(3)

This is useful when a project is built with Makefiles and erlc(1)
instead of EMakefiles. Tracking dependencies by hand is error-prone and
it becomes painful when using external application headers like EUnit's
one.

A dependencies Makefile will look like this:

    module.beam: module.erl \
      /usr/local/lib/erlang/lib/eunit-2.1.4/include/eunit.hrl \
      header.hrl

When included in the main Makefile, 'module' will be recompiled only
when needed.

GCC offers the same feature and new erlc(1) options are compatible with
it.

More informations at:
    http://wiki.github.com/dumbbell/otp/dependencies-makefile

1 files changed, 193 insertions, 1 deletions

diff --git a/lib/compiler/src/compile.erl b/lib/compiler/src/compile.erl
index 26da3ecad2..38603a76a1 100644
--- a/lib/compiler/src/compile.erl
+++ b/lib/compiler/src/compile.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 1996-2010. All Rights Reserved.
+%% Copyright Ericsson AB 1996-2011. 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
@@ -205,6 +205,9 @@ format_error(write_error) ->
 format_error({rename,From,To,Error}) ->
     io_lib:format("failed to rename ~s to ~s: ~s",
 		  [From,To,file:format_error(Error)]);
+format_error({delete,File,Error}) ->
+    io_lib:format("failed to delete file ~s: ~s",
+		  [File,file:format_error(Error)]);
 format_error({delete_temp,File,Error}) ->
     io_lib:format("failed to delete temporary file ~s: ~s",
 		  [File,file:format_error(Error)]);
@@ -435,6 +438,8 @@ passes(file, Opts) ->
 %%			file will be Ext.  (Ext should not contain
 %%			a period.)   No more passes will be run.
 %%
+%%    done              End compilation at this point.
+%%
 %%    {done,Ext}        End compilation at this point. Produce a listing
 %%                      as with {listing,Ext}, unless 'binary' is
 %%                      specified, in which case the current
@@ -468,6 +473,8 @@ select_passes([{src_listing,Ext}|_], _Opts) ->
     [{listing,fun (St) -> src_listing(Ext, St) end}];
 select_passes([{listing,Ext}|_], _Opts) ->
     [{listing,fun (St) -> listing(Ext, St) end}];
+select_passes([done|_], _Opts) ->
+    [];
 select_passes([{done,Ext}|_], Opts) ->
     select_passes([{unless,binary,{listing,Ext}}], Opts);
 select_passes([{iff,Flag,Pass}|Ps], Opts) ->
@@ -550,6 +557,13 @@ select_list_passes_1([], _, Acc) ->
 
 standard_passes() ->
     [?pass(transform_module),
+
+     {iff,makedep,[
+	 ?pass(makedep),
+	 {unless,binary,?pass(makedep_output)}
+       ]},
+     {iff,makedep,done},
+
      {iff,'dpp',{listing,"pp"}},
      ?pass(lint_module),
      {iff,'P',{src_listing,"P"}},
@@ -901,6 +915,184 @@ core_lint_module(St) ->
 			      errors=St#compile.errors ++ Es}}
     end.
 
+makedep(#compile{code=Code,options=Opts}=St) ->
+    Ifile = St#compile.ifile,
+    Ofile = St#compile.ofile,
+
+    %% Get the target of the Makefile rule.
+    Target0 =
+	case proplists:get_value(makedep_target, Opts) of
+	    undefined ->
+		%% The target is derived from the output filename: possibly
+		%% remove the current working directory to obtain a relative
+		%% path.
+		shorten_filename(Ofile);
+	    T ->
+		%% The caller specified one.
+		T
+	end,
+
+    %% Quote the target is the called asked for this.
+    Target1 = case proplists:get_value(makedep_quote_target, Opts) of
+		  true ->
+		      %% For now, only "$" is replaced by "$$".
+		      Fun = fun
+				($$) -> "$$";
+				(C)  -> C
+			    end,
+		      map(Fun, Target0);
+		  _ ->
+		      Target0
+	      end,
+    Target = Target1 ++ ":",
+
+    %% List the dependencies (includes) for this target.
+    {MainRule,PhonyRules} = makedep_add_headers(
+      Ifile,          % The input file name.
+      Code,           % The parsed source.
+      [],             % The list of dependencies already added.
+      length(Target), % The current line length.
+      Target,         % The target.
+      "",             % Phony targets.
+      Opts),
+
+    %% Prepare the content of the Makefile. For instance:
+    %%   hello.erl: hello.hrl common.hrl
+    %%
+    %% Or if phony targets are enabled:
+    %%   hello.erl: hello.hrl common.hrl
+    %%
+    %%   hello.hrl:
+    %%
+    %%   common.hrl:
+    Makefile = case proplists:get_value(makedep_phony, Opts) of
+		   true -> MainRule ++ PhonyRules;
+		   _ -> MainRule
+	       end,
+    {ok,St#compile{code=iolist_to_binary([Makefile,"\n"])}}.
+
+makedep_add_headers(Ifile, [{attribute,_,file,{File,_}}|Rest],
+		    Included, LineLen, MainTarget, Phony, Opts) ->
+    %% The header "File" exists, add it to the dependencies.
+    {Included1,LineLen1,MainTarget1,Phony1} =
+	makedep_add_header(Ifile, Included, LineLen, MainTarget, Phony, File),
+    makedep_add_headers(Ifile, Rest, Included1, LineLen1,
+			MainTarget1, Phony1, Opts);
+makedep_add_headers(Ifile, [{error,{_,epp,{include,file,File}}}|Rest],
+		    Included, LineLen, MainTarget, Phony, Opts) ->
+    %% The header "File" doesn't exist, do we add it to the dependencies?
+    case proplists:get_value(makedep_add_missing, Opts) of
+        true ->
+            {Included1,LineLen1,MainTarget1,Phony1} =
+		makedep_add_header(Ifile, Included, LineLen, MainTarget,
+				   Phony, File),
+            makedep_add_headers(Ifile, Rest, Included1, LineLen1,
+				MainTarget1, Phony1, Opts);
+        _ ->
+            makedep_add_headers(Ifile, Rest, Included, LineLen,
+				MainTarget, Phony, Opts)
+    end;
+makedep_add_headers(Ifile, [_|Rest], Included, LineLen,
+		    MainTarget, Phony, Opts) ->
+    makedep_add_headers(Ifile, Rest, Included,
+			LineLen, MainTarget, Phony, Opts);
+makedep_add_headers(_Ifile, [], _Included, _LineLen,
+		    MainTarget, Phony, _Opts) ->
+    {MainTarget,Phony}.
+
+makedep_add_header(Ifile, Included, LineLen, MainTarget, Phony, File) ->
+    case member(File, Included) of
+	true ->
+	    %% This file was already listed in the dependencies, skip it.
+            {Included,LineLen,MainTarget,Phony};
+	false ->
+            Included1 = [File|Included],
+
+	    %% Remove "./" in front of the dependency filename.
+	    File1 = case File of
+			"./" ++ File0 -> File0;
+			_ -> File
+	    end,
+
+	    %% Prepare the phony target name.
+	    Phony1 = case File of
+			 Ifile -> Phony;
+			 _     -> Phony ++ "\n\n" ++ File1 ++ ":"
+	    end,
+
+	    %% Add the file to the dependencies. Lines longer than 76 columns
+	    %% are splitted.
+	    if
+		LineLen + 1 + length(File1) > 76 ->
+                    LineLen1 = 2 + length(File1),
+                    MainTarget1 = MainTarget ++ " \\\n  " ++ File1,
+                    {Included1,LineLen1,MainTarget1,Phony1};
+		true ->
+                    LineLen1 = LineLen + 1 + length(File1),
+                    MainTarget1 = MainTarget ++ " " ++ File1,
+                    {Included1,LineLen1,MainTarget1,Phony1}
+	    end
+    end.
+
+makedep_output(#compile{code=Code,options=Opts,ofile=Ofile}=St) ->
+    %% Write this Makefile (Code) to the selected output.
+    %% If no output is specified, the default is to write to a file named after
+    %% the output file.
+    Output0 = case proplists:get_value(makedep_output, Opts) of
+		  undefined ->
+		      %% Prepare the default filename.
+		      outfile(filename:basename(Ofile, ".beam"), "Pbeam", Opts);
+		  O ->
+		      O
+	      end,
+
+    %% If the caller specified an io_device(), there's nothing to do. If he
+    %% specified a filename, we must create it. Furthermore, this created file
+    %% must be closed before returning.
+    Ret = case Output0 of
+	      _ when is_list(Output0) ->
+		  case file:delete(Output0) of
+		      Ret2 when Ret2 =:= ok; Ret2 =:= {error,enoent} ->
+			  case file:open(Output0, [write]) of
+			      {ok,IODev} ->
+				  {ok,IODev,true};
+			      {error,Reason2} ->
+				  {error,open,Reason2}
+			  end;
+		      {error,Reason1} ->
+			  {error,delete,Reason1}
+		  end;
+	      _ ->
+		  {ok,Output0,false}
+	  end,
+
+    case Ret of
+	{ok,Output1,CloseOutput} ->
+	    try
+		%% Write the Makefile.
+		io:fwrite(Output1, "~s", [Code]),
+		%% Close the file if relevant.
+		if
+		    CloseOutput -> file:close(Output1);
+		    true -> ok
+		end,
+		{ok,St}
+	    catch
+		exit:_ ->
+		    %% Couldn't write to output Makefile.
+		    Err = {St#compile.ifile,[{none,?MODULE,write_error}]},
+		    {error,St#compile{errors=St#compile.errors++[Err]}}
+	    end;
+	{error,open,Reason} ->
+	    %% Couldn't open output Makefile.
+	    Err = {St#compile.ifile,[{none,?MODULE,{open,Reason}}]},
+	    {error,St#compile{errors=St#compile.errors++[Err]}};
+	{error,delete,Reason} ->
+	    %% Couldn't open output Makefile.
+	    Err = {St#compile.ifile,[{none,?MODULE,{delete,Output0,Reason}}]},
+	    {error,St#compile{errors=St#compile.errors++[Err]}}
+    end.
+
 %% expand_module(State) -> State'
 %%  Do the common preprocessing of the input forms.