Fix compile:forms/1,2 crash when not in an existing directory

compile:forms/1,2 will crash when the current working directory has
been deleted. Fix that problem, and while we are at it, also stop
including {source,""} in module_info() when no source code file is
given.

Reported-at: http://bugs.erlang.org/browse/ERL-113
Reported-by: Adam Lindberg

2 files changed, 16 insertions, 2 deletions

diff --git a/lib/compiler/src/beam_asm.erl b/lib/compiler/src/beam_asm.erl
index 95be471de3..28fd061bdc 100644
--- a/lib/compiler/src/beam_asm.erl
+++ b/lib/compiler/src/beam_asm.erl
@@ -225,10 +225,14 @@ flatten_imports(Imps) ->
     list_to_binary(map(fun({M,F,A}) -> <<M:32,F:32,A:32>> end, Imps)).
 
 build_attributes(Opts, SourceFile, Attr, MD5) ->
+    Misc0 = case SourceFile of
+		[] -> [];
+		[_|_] -> [{source,SourceFile}]
+	    end,
     Misc = case member(slim, Opts) of
 	       false ->
 		   {{Y,Mo,D},{H,Mi,S}} = erlang:universaltime(),
-		   [{time,{Y,Mo,D,H,Mi,S}},{source,SourceFile}];
+		   [{time,{Y,Mo,D,H,Mi,S}}|Misc0];
 	       true -> []
 	   end,
     Compile = [{options,Opts},{version,?COMPILER_VSN}|Misc],
diff --git a/lib/compiler/src/compile.erl b/lib/compiler/src/compile.erl
index 332bc0bdf9..65566df025 100644
--- a/lib/compiler/src/compile.erl
+++ b/lib/compiler/src/compile.erl
@@ -1328,7 +1328,7 @@ save_core_code(St) ->
 
 beam_asm(#compile{ifile=File,code=Code0,
 		  abstract_code=Abst,mod_options=Opts0}=St) ->
-    Source = filename:absname(File),
+    Source = paranoid_absname(File),
     Opts1 = lists:map(fun({debug_info_key,_}) -> {debug_info_key,'********'};
 			 (Other) -> Other
 		      end, Opts0),
@@ -1337,6 +1337,16 @@ beam_asm(#compile{ifile=File,code=Code0,
 	{ok,Code} -> {ok,St#compile{code=Code,abstract_code=[]}}
     end.
 
+paranoid_absname(""=File) ->
+    File;
+paranoid_absname(File) ->
+    case file:get_cwd() of
+	{ok,Cwd} ->
+	    filename:absname(File, Cwd);
+	_ ->
+	    File
+    end.
+
 test_native(#compile{options=Opts}) ->
     %% This test is done late, in case some other option has turned off native.
     %% 'native' given on the command line can be overridden by