Store abstract code in the Dbgi chunk

The new Dbgi chunk returns data in the following format:

    {debug_info_v1, Backend, Data}

This allows compilers to store the debug info in different
formats. In order to retrieve a particular format, for
instance, Erlang Abstract Format, one may invoke:

    Backend:debug_info(erlang_v1, Module, Data, Opts)

Besides introducing the chunk above, this commit also:

  * Changes beam_lib:chunk(Beam, [:abstract_code]) to
    read from the new Dbgi chunk while keeping backwards
    compatibility with old .beams

  * Adds the {debug_info, {Backend, Data}} option to
    compile:file/2 and friends that are stored in the
    Dbgi chunk. This allows the debug info encryption
    mechanism to work across compilers

  * Improves dialyzer to work directly on Core Erlang,
    allowing languages that do not have the Erlang
    Abstract Format to be dialyzer as long as they emit
    the new chunk and their backend implementation is
    available

Backwards compatibility is kept across the board except
for those calling beam_lib:chunk(Beam, ["Abst"]), as the
old chunk is no longer available. Note however the "Abst"
chunk has always been optional.

Future OTP versions may remove parsing the "Abst" chunk
altogether from beam_lib once Erlang 19 and earlier is no
longer supported.

The current Dialyzer implementation still supports earlier
.beam files and such may also be removed in future versions.

1 files changed, 51 insertions, 38 deletions

diff --git a/lib/compiler/src/compile.erl b/lib/compiler/src/compile.erl
index 019d8ba864..b106f856ee 100644
--- a/lib/compiler/src/compile.erl
+++ b/lib/compiler/src/compile.erl
@@ -198,9 +198,9 @@ expand_opts(Opts0) ->
     %% {debug_info_key,Key} implies debug_info.
     Opts = case {proplists:get_value(debug_info_key, Opts0),
 		 proplists:get_value(encrypt_debug_info, Opts0),
-		 proplists:get_bool(debug_info, Opts0)} of
+		 proplists:get_value(debug_info, Opts0)} of
 	       {undefined,undefined,_} -> Opts0;
-	       {_,_,false} -> [debug_info|Opts0];
+	       {_,_,undefined} -> [debug_info|Opts0];
 	       {_,_,_} -> Opts0
 	   end,
     foldr(fun expand_opt/2, [], Opts).
@@ -302,7 +302,7 @@ format_error_reason(Reason) ->
 		  ofile=""    :: file:filename(),
 		  module=[]   :: module() | [],
 		  core_code=[] :: cerl:c_module() | [],
-		  abstract_code=[] :: binary() | [], %Abstract code for debugger.
+		  abstract_code=[] :: abstract_code(), %Abstract code for debugger.
 		  options=[]  :: [option()],  %Options for compilation
 		  mod_options=[]  :: [option()], %Options for module_info
                   encoding=none :: none | epp:source_encoding(),
@@ -1315,44 +1315,43 @@ core_inline_module(Code0, #compile{options=Opts}=St) ->
     Code = cerl_inline:core_transform(Code0, Opts),
     {ok,Code,St}.
 
-save_abstract_code(Code, #compile{ifile=File}=St) ->
-    case abstract_code(Code, St) of
-	{ok,Abstr} ->
-	    {ok,Code,St#compile{abstract_code=Abstr}};
-	{error,Es} ->
-	    {error,St#compile{errors=St#compile.errors ++ [{File,Es}]}}
-    end.
+save_abstract_code(Code, St) ->
+    {ok,Code,St#compile{abstract_code=erl_parse:anno_to_term(Code)}}.
+
+debug_info(#compile{module=Module,mod_options=Opts0,ofile=OFile,abstract_code=Abst}) ->
+    AbstOpts = cleanup_compile_options(Opts0),
+    Opts1 = proplists:delete(debug_info, Opts0),
+    {Backend,Metadata,Opts2} =
+	case proplists:get_value(debug_info, Opts0, false) of
+	    {OptBackend,OptMetadata} when is_atom(OptBackend) -> {OptBackend,OptMetadata,Opts1};
+	    false -> {erl_abstract_code,{none,AbstOpts},Opts1};
+	    true -> {erl_abstract_code,{Abst,AbstOpts},[debug_info | Opts1]}
+	end,
+    DebugInfo = erlang:term_to_binary({debug_info_v1,Backend,Metadata}, [compressed]),
 
-abstract_code(Code0, #compile{options=Opts,ofile=OFile}) ->
-    Code = erl_parse:anno_to_term(Code0),
-    Abstr = erlang:term_to_binary({raw_abstract_v1,Code}, [compressed]),
-    case member(encrypt_debug_info, Opts) of
+    case member(encrypt_debug_info, Opts2) of
 	true ->
-	    case keyfind(debug_info_key, 1, Opts) of
-		{_,Key} ->
-		    encrypt_abs_code(Abstr, Key);
+	    case lists:keytake(debug_info_key, 1, Opts2) of
+		{value,{_, Key},Opts3} ->
+		    encrypt_debug_info(DebugInfo, Key, [{debug_info_key,'********'} | Opts3]);
 		false ->
-		    %% Note: #compile.module has not been set yet.
-		    %% Here is an approximation that should work for
-		    %% all valid cases.
-		    Module = list_to_atom(filename:rootname(filename:basename(OFile))),
-		    Mode = proplists:get_value(crypto_mode, Opts, des3_cbc),
+		    Mode = proplists:get_value(crypto_mode, Opts2, des3_cbc),
 		    case beam_lib:get_crypto_key({debug_info, Mode, Module, OFile}) of
 			error ->
 			    {error, [{none,?MODULE,no_crypto_key}]};
 			Key ->
-			    encrypt_abs_code(Abstr, {Mode, Key})
+			    encrypt_debug_info(DebugInfo, {Mode, Key}, Opts2)
 		    end
 	    end;
 	false ->
-	    {ok,Abstr}
+	    {ok,DebugInfo,Opts2}
     end.
 
-encrypt_abs_code(Abstr, Key0) ->
+encrypt_debug_info(DebugInfo, Key, Opts) ->
     try
-	RealKey = generate_key(Key0),
+	RealKey = generate_key(Key),
 	case start_crypto() of
-	    ok -> {ok,encrypt(RealKey, Abstr)};
+	    ok -> {ok,encrypt(RealKey, DebugInfo),Opts};
 	    {error,_}=E -> E
 	end
     catch
@@ -1360,6 +1359,20 @@ encrypt_abs_code(Abstr, Key0) ->
 	    {error,[{none,?MODULE,bad_crypto_key}]}
     end.
 
+cleanup_compile_options(Opts) ->
+    lists:filter(fun keep_compile_option/1, Opts).
+
+%% We are storing abstract, not asm or core.
+keep_compile_option(from_asm) -> false;
+keep_compile_option(from_core) -> false;
+%% Parse transform and macros have already been applied.
+keep_compile_option({parse_transform, _}) -> false;
+keep_compile_option({d, _, _}) -> false;
+%% Do not affect compilation result on future calls.
+keep_compile_option({outdir, _}) -> false;
+keep_compile_option(warnings_as_errors) -> false;
+keep_compile_option(Option) -> effects_code_generation(Option).
+
 start_crypto() ->
     try crypto:start() of
 	{error,{already_started,crypto}} -> ok;
@@ -1386,16 +1399,16 @@ encrypt({des3_cbc=Type,Key,IVec,BlockSize}, Bin0) ->
 save_core_code(Code, St) ->
     {ok,Code,St#compile{core_code=cerl:from_records(Code)}}.
 
-beam_asm(Code0, #compile{ifile=File,abstract_code=Abst,extra_chunks=ExtraChunks,
-			 options=CompilerOpts,mod_options=Opts0}=St) ->
-    Source = paranoid_absname(File),
-    Opts1 = lists:map(fun({debug_info_key,_}) -> {debug_info_key,'********'};
-			 (Other) -> Other
-		      end, Opts0),
-    Opts2 = [O || O <- Opts1, effects_code_generation(O)],
-    Chunks = [{<<"Abst">>, Abst} | ExtraChunks],
-    case beam_asm:module(Code0, Chunks, Source, Opts2, CompilerOpts) of
-	{ok,Code} -> {ok,Code,St#compile{abstract_code=[]}}
+beam_asm(Code0, #compile{ifile=File,extra_chunks=ExtraChunks,options=CompilerOpts}=St) ->
+    case debug_info(St) of
+	{ok,DebugInfo,Opts0} ->
+	    Source = paranoid_absname(File),
+	    Opts1 = [O || O <- Opts0, effects_code_generation(O)],
+	    Chunks = [{<<"Dbgi">>, DebugInfo} | ExtraChunks],
+	    {ok,Code} = beam_asm:module(Code0, Chunks, Source, Opts1, CompilerOpts),
+	    {ok,Code,St#compile{abstract_code=[]}};
+	{error,Es} ->
+	    {error,St#compile{errors=St#compile.errors ++ [{File,Es}]}}
     end.
 
 paranoid_absname(""=File) ->
@@ -1479,7 +1492,7 @@ embed_native_code(Code, {Architecture,NativeCode}) ->
 %%  errors will be reported).
 
 effects_code_generation(Option) ->
-    case Option of 
+    case Option of
 	beam -> false;
 	report_warnings -> false;
 	report_errors -> false;