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

9 files changed, 338 insertions, 3 deletions

diff --git a/lib/compiler/doc/src/compile.xml b/lib/compiler/doc/src/compile.xml
index c3d65b4cb5..77f3e9b0be 100644
--- a/lib/compiler/doc/src/compile.xml
+++ b/lib/compiler/doc/src/compile.xml
@@ -164,6 +164,70 @@
               for details.</p>
           </item>
 
+          <tag><c>makedep</c></tag>
+          <item>
+            <p>Produce a Makefile rule to track headers dependencies.
+              No object file is produced.
+            </p>
+            <p>By default, this rule is written to
+              <c><![CDATA[<File>.Pbeam]]></c>. However, if the option
+                <c>binary</c> is set, nothing is written and the rule is
+                returned in <c>Binary</c>.
+            </p>
+            <p>For instance, if one has the following module:
+            </p>
+            <code>
+-module(module).
+
+-include_lib("eunit/include/eunit.hrl").
+-include("header.hrl").
+            </code>
+            <p>Here is the Makefile rule generated by this option:
+            </p>
+            <code>
+module.beam: module.erl \
+  /usr/local/lib/erlang/lib/eunit/include/eunit.hrl \
+  header.hrl
+            </code>
+          </item>
+
+          <tag><c>{makedep_output, Output}</c></tag>
+          <item>
+            <p>Write generated rule(s) to <c>Output</c> instead of the
+              default <c><![CDATA[<File>.Pbeam]]></c>. <c>Output</c>
+              can be a filename or an <c>io_device()</c>. To write to
+              stdout, use <c>standard_io</c>. However if <c>binary</c>
+              is set, nothing is written to <c>Output</c> and the
+              result is returned to the caller with
+              <c>{ok, ModuleName, Binary}</c>.
+            </p>
+          </item>
+
+          <tag><c>{makedep_target, Target}</c></tag>
+          <item>
+            <p>Change the name of the rule emitted to <c>Target</c>.
+            </p>
+          </item>
+
+          <tag><c>makedep_quote_target</c></tag>
+          <item>
+            <p>Characters in <c>Target</c> special to make(1) are quoted.
+            </p>
+          </item>
+
+          <tag><c>makedep_add_missing</c></tag>
+          <item>
+            <p>Consider missing headers as generated files and add them to the
+              dependencies.
+            </p>
+          </item>
+
+          <tag><c>makedep_phony</c></tag>
+          <item>
+            <p>Add a phony target for each dependency.
+            </p>
+          </item>
+
           <tag><c>'P'</c></tag>
           <item>
             <p>Produces a listing of the parsed code after preprocessing
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.
 
diff --git a/lib/compiler/test/compile_SUITE.erl b/lib/compiler/test/compile_SUITE.erl
index e1cc5dafb5..cf0f352979 100644
--- a/lib/compiler/test/compile_SUITE.erl
+++ b/lib/compiler/test/compile_SUITE.erl
@@ -25,7 +25,7 @@
 -export([all/1,
 	 app_test/1,
 	 file_1/1, module_mismatch/1, big_file/1, outdir/1, 
-	 binary/1, cond_and_ifdef/1, listings/1, listings_big/1,
+	 binary/1, makedep/1, cond_and_ifdef/1, listings/1, listings_big/1,
 	 other_output/1, package_forms/1, encrypted_abstr/1,
 	 bad_record_use/1, bad_record_use1/1, bad_record_use2/1, strict_record/1,
 	 missing_testheap/1, cover/1, env/1, core/1, asm/1]).
@@ -40,7 +40,7 @@
 all(suite) ->
     test_lib:recompile(?MODULE),
     [app_test,
-     file_1, module_mismatch, big_file, outdir, binary,
+     file_1, module_mismatch, big_file, outdir, binary, makedep,
      cond_and_ifdef, listings, listings_big,
      other_output, package_forms,
      encrypted_abstr,
@@ -132,6 +132,76 @@ binary(Config) when is_list(Config) ->
     ?line test_server:timetrap_cancel(Dog),
     ok.
 
+%% Tests that the dependencies-Makefile-related options work.
+
+makedep(Config) when is_list(Config) ->
+    ?line Dog = test_server:timetrap(test_server:seconds(60)),
+    ?line {Simple,Target} = files(Config, "makedep"),
+    ?line DataDir = ?config(data_dir, Config),
+    ?line SimpleRootname = filename:rootname(Simple),
+    ?line IncludeDir = filename:join(filename:dirname(Simple), "include"),
+    ?line IncludeOptions = [
+      {d,need_foo},
+      {d,foo_value,42},
+      {d,include_generated},
+      {i,IncludeDir}
+    ],
+    %% Basic rule.
+    ?line BasicMf1Name = SimpleRootname ++ "-basic1.mk",
+    ?line {ok,BasicMf1} = file:read_file(BasicMf1Name),
+    ?line {ok,_,Mf1} = compile:file(Simple, [binary,makedep]),
+    ?line BasicMf1 = makedep_canonicalize_result(Mf1, DataDir),
+    %% Basic rule with one existing header.
+    ?line BasicMf2Name = SimpleRootname ++ "-basic2.mk",
+    ?line {ok,BasicMf2} = file:read_file(BasicMf2Name),
+    ?line {ok,_,Mf2} = compile:file(Simple, [binary,makedep|IncludeOptions]),
+    ?line BasicMf2 = makedep_canonicalize_result(Mf2, DataDir),
+    %% Rule with one existing header and one missing header.
+    ?line MissingMfName = SimpleRootname ++ "-missing.mk",
+    ?line {ok,MissingMf} = file:read_file(MissingMfName),
+    ?line {ok,_,Mf3} = compile:file(Simple,
+      [binary,makedep,makedep_add_missing|IncludeOptions]),
+    ?line MissingMf = makedep_canonicalize_result(Mf3, DataDir),
+    %% Rule with modified target.
+    ?line TargetMf1Name = SimpleRootname ++ "-target1.mk",
+    ?line {ok,TargetMf1} = file:read_file(TargetMf1Name),
+    ?line {ok,_,Mf4} = compile:file(Simple,
+      [binary,makedep,{makedep_target,"$target"}|IncludeOptions]),
+    ?line TargetMf1 = makedep_modify_target(
+      makedep_canonicalize_result(Mf4, DataDir), "$$target"),
+    %% Rule with quoted modified target.
+    ?line TargetMf2Name = SimpleRootname ++ "-target2.mk",
+    ?line {ok,TargetMf2} = file:read_file(TargetMf2Name),
+    ?line {ok,_,Mf5} = compile:file(Simple,
+      [binary,makedep,{makedep_target,"$target"},makedep_quote_target|
+        IncludeOptions]),
+    ?line TargetMf2 = makedep_modify_target(
+      makedep_canonicalize_result(Mf5, DataDir), "$$target"),
+    %% Basic rule written to some file.
+    ?line {ok,_} = compile:file(Simple,
+      [makedep,{makedep_output,Target}|IncludeOptions]),
+    ?line {ok,Mf6} = file:read_file(Target),
+    ?line BasicMf2 = makedep_canonicalize_result(Mf6, DataDir),
+
+    ?line ok = file:delete(Target),
+    ?line ok = file:del_dir(filename:dirname(Target)),
+    ?line test_server:timetrap_cancel(Dog),
+    ok.
+
+makedep_canonicalize_result(Mf, DataDir) ->
+    Mf0 = binary_to_list(Mf),
+    %% Replace the Datadir by "$(srcdir)".
+    Mf1 = re:replace(Mf0, DataDir, "$(srcdir)/",
+      [global,multiline,{return,list}]),
+    %% Long lines are splitted, put back everything on one line.
+    Mf2 = re:replace(Mf1, "\\\\\n  ", "", [global,multiline,{return,list}]),
+    list_to_binary(Mf2).
+
+makedep_modify_target(Mf, Target) ->
+    Mf0 = binary_to_list(Mf),
+    Mf1 = re:replace(Mf0, Target, "$target", [{return,list}]),
+    list_to_binary(Mf1).
+
 %% Tests that conditional compilation, defining values, including files work.
 
 cond_and_ifdef(Config) when is_list(Config) ->
diff --git a/lib/compiler/test/compile_SUITE_data/simple-basic1.mk b/lib/compiler/test/compile_SUITE_data/simple-basic1.mk
new file mode 100644
index 0000000000..4073fa82d0
--- /dev/null
+++ b/lib/compiler/test/compile_SUITE_data/simple-basic1.mk
@@ -0,0 +1 @@
+simple.beam: $(srcdir)/simple.erl
diff --git a/lib/compiler/test/compile_SUITE_data/simple-basic2.mk b/lib/compiler/test/compile_SUITE_data/simple-basic2.mk
new file mode 100644
index 0000000000..761d1d9582
--- /dev/null
+++ b/lib/compiler/test/compile_SUITE_data/simple-basic2.mk
@@ -0,0 +1 @@
+simple.beam: $(srcdir)/simple.erl $(srcdir)/include/simple.hrl
diff --git a/lib/compiler/test/compile_SUITE_data/simple-missing.mk b/lib/compiler/test/compile_SUITE_data/simple-missing.mk
new file mode 100644
index 0000000000..b13d44ec36
--- /dev/null
+++ b/lib/compiler/test/compile_SUITE_data/simple-missing.mk
@@ -0,0 +1 @@
+simple.beam: $(srcdir)/simple.erl $(srcdir)/include/simple.hrl generated.hrl
diff --git a/lib/compiler/test/compile_SUITE_data/simple-target1.mk b/lib/compiler/test/compile_SUITE_data/simple-target1.mk
new file mode 100644
index 0000000000..dd9fa0d6e5
--- /dev/null
+++ b/lib/compiler/test/compile_SUITE_data/simple-target1.mk
@@ -0,0 +1 @@
+$target: $(srcdir)/simple.erl $(srcdir)/include/simple.hrl
diff --git a/lib/compiler/test/compile_SUITE_data/simple-target2.mk b/lib/compiler/test/compile_SUITE_data/simple-target2.mk
new file mode 100644
index 0000000000..a5fc6f461d
--- /dev/null
+++ b/lib/compiler/test/compile_SUITE_data/simple-target2.mk
@@ -0,0 +1 @@
+$$target: $(srcdir)/simple.erl $(srcdir)/include/simple.hrl
diff --git a/lib/compiler/test/compile_SUITE_data/simple.erl b/lib/compiler/test/compile_SUITE_data/simple.erl
index 2021056388..8e98852417 100644
--- a/lib/compiler/test/compile_SUITE_data/simple.erl
+++ b/lib/compiler/test/compile_SUITE_data/simple.erl
@@ -37,3 +37,7 @@ foo() ->
     {?included_value, ?foo_value}.
 
 -endif.
+
+-ifdef(include_generated).
+-include("generated.hrl").
+-endif.