From 679274088e5d9825a629ebfd2ba99049030153ba Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Tue, 19 Apr 2016 09:27:10 +0200
Subject: cerl: Add missing API function is_c_map_pattern/1

---
 lib/compiler/src/cerl.erl | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/lib/compiler/src/cerl.erl b/lib/compiler/src/cerl.erl
index d033050d3c..37ec4e97c9 100644
--- a/lib/compiler/src/cerl.erl
+++ b/lib/compiler/src/cerl.erl
@@ -126,6 +126,7 @@
 	 %% keep map exports here for now
 	 c_map_pattern/1,
 	 is_c_map/1,
+	 is_c_map_pattern/1,
 	 map_es/1,
 	 map_arg/1,
 	 update_c_map/3,
@@ -1636,6 +1637,11 @@ is_c_map_empty(#c_map{ es=[] }) -> true;
 is_c_map_empty(#c_literal{val=M}) when is_map(M),map_size(M) =:= 0 -> true;
 is_c_map_empty(_) -> false.
 
+-spec is_c_map_pattern(c_map()) -> boolean().
+
+is_c_map_pattern(#c_map{is_pat=IsPat}) ->
+    IsPat.
+
 -spec ann_c_map([term()], [c_map_pair()]) -> c_map() | c_literal().
 
 ann_c_map(As, Es) ->
-- 
cgit v1.2.3


From 743c176426b956bce36c34ae1b873be9310a91de Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Tue, 19 Apr 2016 09:27:56 +0200
Subject: cerl_trees: Correct handling of maps in label/2

Make sure that we don't convert a map pattern to a map expression.
---
 lib/compiler/src/cerl_trees.erl | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/lib/compiler/src/cerl_trees.erl b/lib/compiler/src/cerl_trees.erl
index 6d38748964..b3decbec1f 100644
--- a/lib/compiler/src/cerl_trees.erl
+++ b/lib/compiler/src/cerl_trees.erl
@@ -61,6 +61,7 @@
 	       map_arg/1, map_es/1,
 	       ann_c_map/3,
 	       update_c_map/3,
+	       is_c_map_pattern/1, ann_c_map_pattern/2,
 	       map_pair_key/1,map_pair_val/1,map_pair_op/1,
 	       ann_c_map_pair/4,
 	       update_c_map_pair/4
@@ -752,10 +753,17 @@ label(T, N, Env) ->
 	    {As, N2} = label_ann(T, N1),
 	    {ann_c_tuple_skel(As, Ts), N2};
  	map ->
-	    {M,  N1} = label(map_arg(T), N, Env),
-	    {Ts, N2} = label_list(map_es(T), N1, Env),
-	    {As, N3} = label_ann(T, N2),
-	    {ann_c_map(As, M, Ts), N3};
+	    case is_c_map_pattern(T) of
+		false ->
+		    {M,  N1} = label(map_arg(T), N, Env),
+		    {Ts, N2} = label_list(map_es(T), N1, Env),
+		    {As, N3} = label_ann(T, N2),
+		    {ann_c_map(As, M, Ts), N3};
+		true ->
+		    {Ts, N1} = label_list(map_es(T), N, Env),
+		    {As, N2} = label_ann(T, N1),
+		    {ann_c_map_pattern(As, Ts), N2}
+	    end;
 	map_pair ->
 	    {Op,  N1} = label(map_pair_op(T), N, Env),
 	    {Key, N2} = label(map_pair_key(T), N1, Env),
-- 
cgit v1.2.3


From ee08efadd1fd5eb0e1f3f13c19d56f0ab0883611 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Mon, 18 Apr 2016 14:36:35 +0200
Subject: core_parse: Handle annotations in more contexts

Annotations would not be accepted for all constructs.
---
 lib/compiler/src/core_parse.yrl | 59 ++++++++++++++++++++++++++++++-----------
 1 file changed, 44 insertions(+), 15 deletions(-)

diff --git a/lib/compiler/src/core_parse.yrl b/lib/compiler/src/core_parse.yrl
index 315324e906..e01f826eef 100644
--- a/lib/compiler/src/core_parse.yrl
+++ b/lib/compiler/src/core_parse.yrl
@@ -47,12 +47,14 @@ receive_expr timeout try_expr
 sequence catch_expr
 variable clause clause_pattern
 
-map_expr map_pairs map_pair map_pair_assoc map_pair_exact
+map_expr anno_map_expr map_pairs anno_map_pair map_pair map_pair_assoc map_pair_exact
 map_pattern map_pair_patterns map_pair_pattern
 
-annotation anno_fun anno_expression anno_expressions
+annotation anno_atom anno_fun anno_expression anno_expressions
 anno_variable anno_variables anno_pattern anno_patterns
 anno_function_name
+anno_literal
+anno_segment anno_segment_pattern
 anno_clause anno_clauses.
 
 Terminals
@@ -90,7 +92,7 @@ module_definition ->
 module_definition ->
     '(' 'module' atom module_export module_attribute module_defs 'end'
 	'-|' annotation ')' :
-	#c_module{anno='$9',name=tok_val('$3'),exports='$4',
+        #c_module{anno='$9',name=#c_literal{val=tok_val('$3')},exports='$4',
 		  attrs='$5',defs='$6'}.
 
 module_export -> '[' ']' : [].
@@ -99,7 +101,7 @@ module_export -> '[' exported_names ']' : '$2'.
 exported_names -> exported_name ',' exported_names : ['$1' | '$3'].
 exported_names -> exported_name : ['$1'].
 
-exported_name -> function_name : '$1'.
+exported_name -> anno_function_name : '$1'.
 
 module_attribute -> 'attributes' '[' ']' : [].
 module_attribute -> 'attributes' '[' attribute_list ']' : '$3'.
@@ -107,8 +109,16 @@ module_attribute -> 'attributes' '[' attribute_list ']' : '$3'.
 attribute_list -> attribute ',' attribute_list : ['$1' | '$3'].
 attribute_list -> attribute : ['$1'].
 
-attribute -> atom '=' literal :
-	{#c_literal{val=tok_val('$1')},'$3'}.
+attribute -> anno_atom '=' anno_literal :
+	{'$1','$3'}.
+
+anno_atom -> atom :
+         cerl:c_atom(tok_val('$1')).
+anno_atom -> '(' atom '-|' annotation ')' :
+         cerl:ann_c_atom('$4', tok_val('$2')).
+
+anno_literal -> literal : '$1'.
+anno_literal -> '(' literal '-|' annotation ')' : cerl:set_ann('$2', '$4').
 
 module_defs -> function_definitions : '$1'.
 
@@ -187,6 +197,8 @@ tuple_pattern -> '{' anno_patterns '}' : c_tuple('$2').
 map_pattern -> '~' '{' '}' '~' : c_map_pattern([]).
 map_pattern -> '~' '{' map_pair_patterns '}' '~' :
 		   c_map_pattern(lists:sort('$3')).
+map_pattern -> '~' '{' map_pair_patterns '|' anno_map_expr '}' '~' :
+		   ann_c_map_pattern('$5', lists:sort('$3')).
 
 map_pair_patterns -> map_pair_pattern : ['$1'].
 map_pair_patterns -> map_pair_pattern ',' map_pair_patterns : ['$1' | '$3'].
@@ -194,6 +206,9 @@ map_pair_patterns -> map_pair_pattern ',' map_pair_patterns : ['$1' | '$3'].
 map_pair_pattern -> anno_expression ':=' anno_pattern :
 			#c_map_pair{op=#c_literal{val=exact},
 				    key='$1',val='$3'}.
+map_pair_pattern -> '(' anno_expression ':=' anno_pattern '-|' annotation ')' :
+			#c_map_pair{anno='$6',op=#c_literal{val=exact},
+				    key='$2',val='$4'}.
 
 cons_pattern -> '[' anno_pattern tail_pattern :
 		    c_cons('$2', '$3').
@@ -206,8 +221,12 @@ tail_pattern -> ',' anno_pattern tail_pattern :
 binary_pattern -> '#' '{' '}' '#' : #c_binary{segments=[]}.
 binary_pattern -> '#' '{' segment_patterns '}' '#' : #c_binary{segments='$3'}.
 
-segment_patterns -> segment_pattern ',' segment_patterns : ['$1' | '$3'].
-segment_patterns -> segment_pattern : ['$1'].
+segment_patterns -> anno_segment_pattern ',' segment_patterns : ['$1' | '$3'].
+segment_patterns -> anno_segment_pattern : ['$1'].
+
+anno_segment_pattern -> segment_pattern : '$1'.
+anno_segment_pattern -> '(' segment_pattern '-|' annotation ')' :
+      cerl:set_ann('$2', '$4').
 
 segment_pattern -> '#' '<' anno_pattern '>' '(' anno_expressions ')':
 	case '$6' of
@@ -289,11 +308,17 @@ tuple -> '{' anno_expressions '}' : c_tuple('$2').
 
 map_expr -> '~' '{' '}' '~' : c_map([]).
 map_expr -> '~' '{' map_pairs '}' '~' : c_map('$3').
-map_expr -> '~' '{' map_pairs '|' variable '}' '~' : ann_c_map([], '$5', '$3').
-map_expr -> '~' '{' map_pairs '|' map_expr '}' '~' : ann_c_map([], '$5', '$3').
+map_expr -> '~' '{' map_pairs '|' anno_variable '}' '~' : ann_c_map([], '$5', '$3').
+map_expr -> '~' '{' map_pairs '|' anno_map_expr '}' '~' : ann_c_map([], '$5', '$3').
 
-map_pairs -> map_pair : ['$1'].
-map_pairs -> map_pair ',' map_pairs : ['$1' | '$3'].
+anno_map_expr -> map_expr : '$1'.
+anno_map_expr -> '(' map_expr '-|' annotation ')' : cerl:set_ann('$2', '$4').
+
+map_pairs -> anno_map_pair : ['$1'].
+map_pairs -> anno_map_pair ',' map_pairs : ['$1' | '$3'].
+
+anno_map_pair -> map_pair : '$1'.
+anno_map_pair -> '(' map_pair '-|' annotation ')' : cerl:set_ann('$2', '$4').
 
 map_pair -> map_pair_assoc : '$1'.
 map_pair -> map_pair_exact : '$1'.
@@ -312,8 +337,11 @@ tail -> ',' anno_expression tail : c_cons('$2', '$3').
 binary -> '#' '{' '}' '#' : #c_literal{val = <<>>}.
 binary -> '#' '{' segments '}' '#' : make_binary('$3').
 
-segments -> segment ',' segments : ['$1' | '$3'].
-segments -> segment : ['$1'].
+segments -> anno_segment ',' segments : ['$1' | '$3'].
+segments -> anno_segment : ['$1'].
+
+anno_segment -> segment : '$1'.
+anno_segment -> '(' segment '-|' annotation ')' : cerl:set_ann('$2', '$4').
 
 segment -> '#' '<' anno_expression '>' '(' anno_expressions ')':
 	case '$6' of
@@ -413,7 +441,8 @@ Erlang code.
 
 -include("core_parse.hrl").
 
--import(cerl, [ann_c_map/3,c_cons/2,c_map/1,c_map_pattern/1,c_tuple/1]).
+-import(cerl, [ann_c_map/3,ann_c_map_pattern/2,c_cons/2,c_map/1,
+	       c_map_pattern/1,c_tuple/1]).
 
 tok_val(T) -> element(3, T).
 tok_line(T) -> element(2, T).
-- 
cgit v1.2.3


From 5a7029ac5afc2a6a55241a2e01d0174741ab4a1c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Wed, 20 Apr 2016 05:20:25 +0200
Subject: core_parse: Don't sort map patterns

If we pretty print to a file and read it back in, we expect to
get the same cerl data structures back.
---
 lib/compiler/src/core_parse.yrl | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/compiler/src/core_parse.yrl b/lib/compiler/src/core_parse.yrl
index e01f826eef..8028aa99bb 100644
--- a/lib/compiler/src/core_parse.yrl
+++ b/lib/compiler/src/core_parse.yrl
@@ -196,9 +196,9 @@ tuple_pattern -> '{' anno_patterns '}' : c_tuple('$2').
 
 map_pattern -> '~' '{' '}' '~' : c_map_pattern([]).
 map_pattern -> '~' '{' map_pair_patterns '}' '~' :
-		   c_map_pattern(lists:sort('$3')).
+		   c_map_pattern('$3').
 map_pattern -> '~' '{' map_pair_patterns '|' anno_map_expr '}' '~' :
-		   ann_c_map_pattern('$5', lists:sort('$3')).
+		   ann_c_map_pattern('$5', '$3').
 
 map_pair_patterns -> map_pair_pattern : ['$1'].
 map_pair_patterns -> map_pair_pattern ',' map_pair_patterns : ['$1' | '$3'].
-- 
cgit v1.2.3


From 3f1a4f5c2ef43c57ed0e82dcd4189aa36e1bf7aa Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Tue, 19 Apr 2016 13:28:16 +0200
Subject: core_pp: Add format_all/1 that prints all annotations

---
 lib/compiler/src/core_pp.erl | 70 ++++++++++++++++++++++++++++----------------
 1 file changed, 44 insertions(+), 26 deletions(-)

diff --git a/lib/compiler/src/core_pp.erl b/lib/compiler/src/core_pp.erl
index 78a081e9ca..c601b13963 100644
--- a/lib/compiler/src/core_pp.erl
+++ b/lib/compiler/src/core_pp.erl
@@ -21,7 +21,7 @@
 
 -module(core_pp).
 
--export([format/1]).
+-export([format/1,format_all/1]).
 
 -include("core_parse.hrl").
 
@@ -38,20 +38,30 @@
 	       item_indent = 2 :: integer(),
 	       body_indent = 4 :: integer(),
 	       tab_width = 8   :: non_neg_integer(),
-	       line = 0        :: integer()}).
+	       line = 0        :: integer(),
+	       clean = true    :: boolean()}).
 
 -spec format(cerl:cerl()) -> iolist().
 
 format(Node) ->
     format(Node, #ctxt{}).
 
-maybe_anno(Node, Fun, Ctxt) ->
+-spec format_all(cerl:cerl()) -> iolist().
+
+format_all(Node) ->
+    format(Node, #ctxt{clean=false}).
+
+maybe_anno(Node, Fun, #ctxt{clean=false}=Ctxt) ->
     As = cerl:get_ann(Node),
-    case get_line(As) of
+    maybe_anno(Node, Fun, Ctxt, As);
+maybe_anno(Node, Fun, #ctxt{clean=true}=Ctxt) ->
+    As0 = cerl:get_ann(Node),
+    case get_line(As0) of
 	none ->
-	    maybe_anno(Node, Fun, Ctxt, As);
+	    maybe_anno(Node, Fun, Ctxt, As0);
   	Line ->
-	    if  Line > Ctxt#ctxt.line ->
+	    As = strip_line(As0),
+	    if Line > Ctxt#ctxt.line ->
 		    [io_lib:format("%% Line ~w",[Line]),
 		     nl_indent(Ctxt),
 		     maybe_anno(Node, Fun, Ctxt#ctxt{line = Line}, As)
@@ -61,19 +71,16 @@ maybe_anno(Node, Fun, Ctxt) ->
 	    end
     end.
 
-maybe_anno(Node, Fun, Ctxt, As) ->
-    case strip_line(As) of
-	[] ->
-	    Fun(Node, Ctxt);
-	List ->
-	    Ctxt1 = add_indent(Ctxt, 2),
-	    Ctxt2 = add_indent(Ctxt1, 3),
-	    ["( ",
-	     Fun(Node, Ctxt1),
-	     nl_indent(Ctxt1),
-	     "-| ",format_anno(List, Ctxt2)," )"
-	    ]
-    end.
+maybe_anno(Node, Fun, Ctxt, []) ->
+    Fun(Node, Ctxt);
+maybe_anno(Node, Fun, Ctxt, List) ->
+    Ctxt1 = add_indent(Ctxt, 2),
+    Ctxt2 = add_indent(Ctxt1, 3),
+    ["( ",
+     Fun(Node, Ctxt1),
+     nl_indent(Ctxt1),
+     "-| ",format_anno(List, Ctxt2)," )"
+    ].
 
 format_anno([_|_]=List, Ctxt) ->
     [$[,format_anno_list(List, Ctxt),$]];
@@ -172,7 +179,8 @@ format_1(#c_tuple{es=Es}, Ctxt) ->
      format_hseq(Es, ",", add_indent(Ctxt, 1), fun format/2),
      $}
     ];
-format_1(#c_map{arg=#c_literal{val=M},es=Es}, Ctxt) when is_map(M),map_size(M)=:=0 ->
+format_1(#c_map{arg=#c_literal{anno=[],val=M},es=Es}, Ctxt)
+  when is_map(M), map_size(M) =:= 0 ->
     ["~{",
      format_hseq(Es, ",", add_indent(Ctxt, 1), fun format/2),
      "}~"
@@ -195,9 +203,16 @@ format_1(#c_values{es=Es}, Ctxt) ->
 format_1(#c_alias{var=V,pat=P}, Ctxt) ->
     Txt = [format(V, Ctxt)|" = "],
     [Txt|format(P, add_indent(Ctxt, width(Txt, Ctxt)))];
-format_1(#c_let{vars=Vs0,arg=A,body=B}, Ctxt) ->
-    Vs = [cerl:set_ann(V, []) || V <- Vs0],
-    case is_simple_term(A) of
+format_1(#c_let{anno=Anno0,vars=Vs0,arg=A0,body=B}, #ctxt{clean=Clean}=Ctxt) ->
+    {Vs,A,Anno} = case Clean of
+		      false ->
+			  {Vs0,A0,Anno0};
+		      true ->
+			  {[cerl:set_ann(V, []) || V <- Vs0],
+			   cerl:set_ann(A0, []),
+			   []}
+		  end,
+    case is_simple_term(A) andalso Anno =:= [] of
 	false ->
 	    Ctxt1 = add_indent(Ctxt, Ctxt#ctxt.body_indent),
 	    ["let ",
@@ -214,7 +229,7 @@ format_1(#c_let{vars=Vs0,arg=A,body=B}, Ctxt) ->
 	    ["let ",
 	     format_values(Vs, add_indent(Ctxt, 4)),
 	     " = ",
-	     format(cerl:set_ann(A, []), Ctxt1),
+	     format(A, Ctxt1),
 	     nl_indent(Ctxt),
 	     "in  "
 	     | format(B, add_indent(Ctxt, 4))
@@ -362,7 +377,10 @@ format_values(Vs, Ctxt) ->
      format_hseq(Vs, ",", add_indent(Ctxt, 1), fun format/2),
      $>].
 
-format_bitstr(#c_bitstr{val=V,size=S,unit=U,type=T,flags=Fs}, Ctxt0) ->
+format_bitstr(Node, Ctxt) ->
+    maybe_anno(Node, fun do_format_bitstr/2, Ctxt).
+
+do_format_bitstr(#c_bitstr{val=V,size=S,unit=U,type=T,flags=Fs}, Ctxt0) ->
     Vs = [S, U, T, Fs],
     Ctxt1 = add_indent(Ctxt0, 2),
     Val = format(V, Ctxt1),
@@ -387,7 +405,7 @@ format_clause_1(#c_clause{pats=Ps,guard=G,body=B}, Ctxt) ->
 					 width(Ptxt, Ctxt) + 6))];
 	 false ->
 	     [nl_indent(Ctxt2), "when ",
-	      format_guard(G, add_indent(Ctxt2, 2))]
+	      format_guard(G, add_indent(set_class(Ctxt2, expr), 2))]
      end++
      " ->",
      nl_indent(Ctxt2)
-- 
cgit v1.2.3


From 232cb70f33fa2618412b814b8f9aa78d1d20ef25 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Tue, 19 Apr 2016 14:01:39 +0200
Subject: core_pp: Print {file,File} annotations more compactly

This will speed up test cases that print all annotations.
---
 lib/compiler/src/core_pp.erl | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/lib/compiler/src/core_pp.erl b/lib/compiler/src/core_pp.erl
index c601b13963..88275998be 100644
--- a/lib/compiler/src/core_pp.erl
+++ b/lib/compiler/src/core_pp.erl
@@ -84,6 +84,9 @@ maybe_anno(Node, Fun, Ctxt, List) ->
 
 format_anno([_|_]=List, Ctxt) ->
     [$[,format_anno_list(List, Ctxt),$]];
+format_anno({file,Name}, _Ctxt) ->
+    %% Optimization: Reduces file size considerably.
+    io_lib:format("{'file',~p}", [Name]);
 format_anno(Tuple, Ctxt) when is_tuple(Tuple) ->
     [${,format_anno_list(tuple_to_list(Tuple), Ctxt),$}];
 format_anno(Val, Ctxt) when is_atom(Val) ->
-- 
cgit v1.2.3


From b5d290306a9be6a22e63df34456a880074b324cc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Tue, 19 Apr 2016 13:32:05 +0200
Subject: v3_core: Construct {badmap,Map} as literal if possible

---
 lib/compiler/src/v3_core.erl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/compiler/src/v3_core.erl b/lib/compiler/src/v3_core.erl
index de775097e3..3299149457 100644
--- a/lib/compiler/src/v3_core.erl
+++ b/lib/compiler/src/v3_core.erl
@@ -784,7 +784,7 @@ badmap_term(_Map, #core{in_guard=true}) ->
     %% since it is not user-visible.
     #c_literal{val=badmap};
 badmap_term(Map, #core{in_guard=false}) ->
-    #c_tuple{es=[#c_literal{val=badmap},Map]}.
+    c_tuple([#c_literal{val=badmap},Map]).
 
 map_build_pairs(Map, Es0, Ann, St0) ->
     {Es,Pre,St1} = map_build_pairs_1(Es0, St0),
-- 
cgit v1.2.3


From 9f1a4c94b57d3ead1d098d236260771f935336c8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Wed, 20 Apr 2016 05:47:01 +0200
Subject: Add compile_SUITE:core_roundtrip/1

When debugging, it is important that we can trust the Core Erlang
pretty printer and Core Erlang parser.
---
 lib/compiler/test/compile_SUITE.erl | 119 +++++++++++++++++++++++++++++++++++-
 1 file changed, 117 insertions(+), 2 deletions(-)

diff --git a/lib/compiler/test/compile_SUITE.erl b/lib/compiler/test/compile_SUITE.erl
index e1db99b357..72e88370b6 100644
--- a/lib/compiler/test/compile_SUITE.erl
+++ b/lib/compiler/test/compile_SUITE.erl
@@ -31,7 +31,8 @@
 	 binary/1, makedep/1, cond_and_ifdef/1, listings/1, listings_big/1,
 	 other_output/1, encrypted_abstr/1,
 	 strict_record/1,
-	 missing_testheap/1, cover/1, env/1, core/1, asm/1,
+	 missing_testheap/1, cover/1, env/1, core/1,
+	 core_roundtrip/1, asm/1,
 	 sys_pre_attributes/1, dialyzer/1,
 	 warnings/1, pre_load_check/1
 	]).
@@ -50,7 +51,7 @@ all() ->
      binary, makedep, cond_and_ifdef, listings, listings_big,
      other_output, encrypted_abstr,
      strict_record,
-     missing_testheap, cover, env, core, asm,
+     missing_testheap, cover, env, core, core_roundtrip, asm,
      sys_pre_attributes, dialyzer, warnings, pre_load_check].
 
 groups() -> 
@@ -790,6 +791,120 @@ compile_forms(Forms, Opts) ->
 	Other -> throw({error,Other})
     end.
 
+%% Pretty-print core and read it back. Should be identical.
+
+core_roundtrip(Config) ->
+    PrivDir = proplists:get_value(priv_dir, Config),
+    Outdir = filename:join(PrivDir, atom_to_list(?FUNCTION_NAME)),
+    ok = file:make_dir(Outdir),
+
+    Wc = filename:join(filename:dirname(code:which(?MODULE)), "*.beam"),
+    TestBeams = filelib:wildcard(Wc),
+    test_lib:p_run(fun(F) -> do_core_roundtrip(F, Outdir) end, TestBeams).
+
+do_core_roundtrip(Beam, Outdir) ->
+    try
+	{ok,{Mod,[{abstract_code,{raw_abstract_v1,Abstr}}]}} =
+	    beam_lib:chunks(Beam, [abstract_code]),
+	do_core_roundtrip_1(Mod, Abstr, Outdir)
+    catch
+	throw:{error,Error} ->
+	    io:format("*** compilation failure '~p' for file ~s\n",
+		      [Error,Beam]),
+	    error;
+	Class:Error ->
+	    io:format("~p: ~p ~p\n~p\n",
+		      [Beam,Class,Error,erlang:get_stacktrace()]),
+	    error
+    end.
+
+do_core_roundtrip_1(Mod, Abstr, Outdir) ->
+    {ok,Mod,Core0} = compile:forms(Abstr, [to_core0]),
+    do_core_roundtrip_2(Mod, Core0, Outdir),
+
+    %% Primarily, test that annotations are accepted for all
+    %% constructs. Secondarily, smoke test cerl_trees:label/1.
+    {Core,_} = cerl_trees:label(Core0),
+    do_core_roundtrip_2(Mod, Core, Outdir).
+
+do_core_roundtrip_2(M, Core0, Outdir) ->
+    CoreFile = filename:join(Outdir, atom_to_list(M)++".core"),
+    CorePP = core_pp:format_all(Core0),
+    ok = file:write_file(CoreFile, CorePP),
+
+    %% Parse the .core file and return the result as Core Erlang Terms.
+    Core2 = case compile:file(CoreFile, [report_errors,from_core,
+					 no_copt,to_core,binary]) of
+		{ok,M,Core1} -> Core1;
+		Other -> throw({error,Other})
+	    end,
+    Core = undo_var_translation(Core2),
+    ok = file:delete(CoreFile),
+
+    case cmp_core(Core0, Core, M) of
+	true -> ok;
+	false -> error
+    end,
+
+    ok.
+
+undo_var_translation(Tree) ->
+    F = fun(Node) ->
+		case cerl:is_c_var(Node) of
+		    true ->
+			Name0 = cerl:var_name(Node),
+			try atom_to_list(Name0) of
+			    "_X"++Name ->
+				cerl:update_c_var(Node, list_to_atom(Name));
+			    "_"++Name ->
+				cerl:update_c_var(Node, list_to_atom(Name));
+			    _ ->
+				Node
+			catch
+			    error:badarg ->
+				Node
+
+			end;
+		    false ->
+			Node
+		end
+	end,
+    cerl_trees:map(F, Tree).
+
+cmp_core(E, E, _Mod) ->
+    true;
+cmp_core(M1, M2, Mod) ->
+    cmp_core_fs(cerl:module_defs(M1), cerl:module_defs(M2), Mod).
+
+cmp_core_fs([F1|T1], [F2|T2], Mod) ->
+    cmp_core_f(F1, F2, Mod) andalso cmp_core_fs(T1, T2, Mod);
+cmp_core_fs([], [], _Mod) ->
+    true;
+cmp_core_fs(_, _, _Mod) ->
+    false.
+
+cmp_core_f(E, E, _Mod) ->
+    true;
+cmp_core_f({Name,F1}, {Name,F2}, Mod) ->
+    case diff(F1, F2) of
+	F1 ->
+	    true;
+	Diff ->
+	    io:format("~p ~p:\n~p\n", [Mod,Name,Diff]),
+	    false
+    end.
+
+diff(E, E) ->
+    E;
+diff([H1|T1], [H2|T2]) ->
+    [diff(H1, H2)|diff(T1, T2)];
+diff(T1, T2) when tuple_size(T1) =:= tuple_size(T2) ->
+    L = diff(tuple_to_list(T1), tuple_to_list(T2)),
+    list_to_tuple(L);
+diff(E1, E2) ->
+    {'DIFF',E1,E2}.
+
+
 %% Compile to Beam assembly language (.S) and then try to
 %% run .S through the compiler again.
 
-- 
cgit v1.2.3