Use compile source info in debugger

Prior to this commit, the debugger relied on a simple heuristic
that traverses directory from the beam file to find a source file.
The heuristic was maintained with this patch but, if it fails,
it fallbacks to the source value in the module compile info.

In order to illustrate how it works, one of the tests that
could not find its source now passes successfully (showing the
source lookup is more robust).

1 files changed, 15 insertions, 3 deletions

diff --git a/lib/debugger/src/int.erl b/lib/debugger/src/int.erl
index 4f54beb45b..1e43d1858a 100644
--- a/lib/debugger/src/int.erl
+++ b/lib/debugger/src/int.erl
@@ -547,7 +547,7 @@ load({Mod, Src, Beam, BeamBin, Exp, Abst}, Dist) ->
 check_module(Mod) ->
     case code:which(Mod) of
 	Beam when is_list(Beam) ->
-	    case find_src(Beam) of
+	    case find_src(Mod, Beam) of
 		Src when is_list(Src) ->
 		    check_application(Src),
 		    case check_beam(Beam) of
@@ -608,7 +608,7 @@ check_application2("gs-"++_) -> throw({error,{app,gs}});
 check_application2("debugger-"++_) -> throw({error,{app,debugger}});
 check_application2(_) -> ok.
 
-find_src(Beam) ->
+find_src(Mod, Beam) ->
     Src0 = filename:rootname(Beam) ++ ".erl",
     case is_file(Src0) of
 	true -> Src0;
@@ -618,10 +618,22 @@ find_src(Beam) ->
 				 filename:basename(Src0)]),
 	    case is_file(Src) of
 		true -> Src;
-		false -> error
+		false -> find_src_from_module(Mod)
 	    end
     end.
 
+find_src_from_module(Mod) ->
+    Compile = Mod:module_info(compile),
+    case lists:keyfind(source, 1, Compile) of
+	{source, Src} ->
+	    case is_file(Src) of
+		true -> Src;
+		false -> error
+	    end;
+	false ->
+	    error
+    end.
+
 find_beam(Mod, Src) ->
     SrcDir = filename:dirname(Src),
     BeamFile = atom_to_list(Mod) ++ code:objfile_extension(),