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

7 files changed, 81 insertions, 2 deletions

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.