Officially support building assembler files

erlc is wired to treat *.S files as assembler and build them as
compile:file(File, [from_asm]), but this is not documented. There's also
a documented compile:file/2 option called 'asm' (mapping to 'from_asm'),
but the wording discourages its use. All of this has been in place and
in use for a long time. Therefore, it should be supported officially.

To fix that, make the following changes:
 * document erlc handling of *.core files
 * un-document 'asm' and document 'from_asm' instead
 * deprecate 'asm'

While at it, fix a minor typo in the test suite.

4 files changed, 14 insertions, 6 deletions

diff --git a/erts/doc/src/erlc.xml b/erts/doc/src/erlc.xml
index 10cab344b0..2df026aef5 100644
--- a/erts/doc/src/erlc.xml
+++ b/erts/doc/src/erlc.xml
@@ -234,6 +234,11 @@ erlc +export_all file.erl</pre>
           from the shell.</p>
         <p>Supported options: -I, -o, -D, -v, -W, -b.</p>
       </item>
+      <tag>.S</tag>
+      <item>
+        <p>Erlang assembler source code. It generates a <c><![CDATA[.beam]]></c> file.</p>
+        <p>Supported options: same as for .erl.</p>
+      </item>
       <tag>.yrl</tag>
       <item>
         <p>Yecc source code. It generates an <c><![CDATA[.erl]]></c> file.</p>
diff --git a/lib/compiler/doc/src/compile.xml b/lib/compiler/doc/src/compile.xml
index 73d75851cf..eb7745890e 100644
--- a/lib/compiler/doc/src/compile.xml
+++ b/lib/compiler/doc/src/compile.xml
@@ -350,12 +350,11 @@ module.beam: module.erl \
               parsed code before the code is checked for errors.</p>
           </item>
 
-	  <tag><c>asm</c></tag>
+	  <tag><c>from_asm</c></tag>
           <item>
             <p>The input file is expected to be assembler code (default
 	      file suffix ".S"). Note that the format of assembler files
-              is not documented, and may change between releases - this
-              option is primarily for internal debugging use.</p>
+              is not documented, and may change between releases.</p>
           </item>
 
           <tag><c>no_strict_record_tests</c></tag>
diff --git a/lib/compiler/src/compile.erl b/lib/compiler/src/compile.erl
index 47d446273b..38a733751a 100644
--- a/lib/compiler/src/compile.erl
+++ b/lib/compiler/src/compile.erl
@@ -417,6 +417,10 @@ pass(from_core) ->
 pass(from_asm) ->
     {".S",[?pass(beam_consult_asm)|asm_passes()]};
 pass(asm) ->
+    %% TODO: remove 'asm' in R18
+    io:format("compile:file/2 option 'asm' has been deprecated and will be "
+	      "removed in R18.~n"
+	      "Use 'from_asm' instead.~n"),
     pass(from_asm);
 pass(from_beam) ->
     {".beam",[?pass(read_beam_file)|binary_passes()]};
@@ -1613,7 +1617,7 @@ compile_beam(File0, _OutFile, Opts) ->
 
 compile_asm(File0, _OutFile, Opts) ->
     File = shorten_filename(File0),
-    case file(File, [asm|make_erl_options(Opts)]) of
+    case file(File, [from_asm|make_erl_options(Opts)]) of
 	{ok,_Mod} -> ok;
 	Other -> Other
     end.
diff --git a/lib/compiler/test/compile_SUITE.erl b/lib/compiler/test/compile_SUITE.erl
index 1dc1ddb653..4ec75d015e 100644
--- a/lib/compiler/test/compile_SUITE.erl
+++ b/lib/compiler/test/compile_SUITE.erl
@@ -769,8 +769,8 @@ do_core({M,A}, Outdir) ->
 	    error
     end.
 
-%% Compile to Beam assembly language (.S) and the try to
-%% run .S throught the compiler again.
+%% Compile to Beam assembly language (.S) and then try to
+%% run .S through the compiler again.
 
 asm(Config) when is_list(Config) ->
     ?line Dog = test_server:timetrap(test_server:minutes(20)),