Merge branch 'maint'

* maint:
  Eliminate crash in v3_codegen

2 files changed, 82 insertions, 32 deletions

diff --git a/lib/compiler/src/v3_codegen.erl b/lib/compiler/src/v3_codegen.erl
index 5083995f30..6f1912c616 100644
--- a/lib/compiler/src/v3_codegen.erl
+++ b/lib/compiler/src/v3_codegen.erl
@@ -1330,12 +1330,13 @@ bif_cg(Bif, As, [{var,V}], Le, Vdb, Bef, St0) ->
     %% that we save any variable that will be live after this BIF call.
 
     MayFail = not erl_bifs:is_safe(erlang, Bif, length(As)),
-    {Sis,Int0} = case St0#cg.in_catch andalso
-		     St0#cg.bfail =:= 0 andalso
-		     MayFail of
-		     true -> adjust_stack(Bef, Le#l.i, Le#l.i+1, Vdb);
-		     false -> {[],Bef}
-		 end,
+    {Sis,Int0} =
+	case MayFail of
+	    true ->
+		maybe_adjust_stack(Bef, Le#l.i, Le#l.i+1, Vdb, St0);
+	    false ->
+		{[],Bef}
+	end,
     Int1 = clear_dead(Int0, Le#l.i, Vdb),
     Reg = put_reg(V, Int1#sr.reg),
     Int = Int1#sr{reg=Reg},
@@ -1366,11 +1367,7 @@ gc_bif_cg(Bif, As, [{var,V}], Le, Vdb, Bef, St0) ->
     %%   Currently, we are somewhat pessimistic in
     %% that we save any variable that will be live after this BIF call.
 
-    {Sis,Int0} =
-	case St0#cg.in_catch andalso St0#cg.bfail =:= 0 of
-	    true -> adjust_stack(Bef, Le#l.i, Le#l.i+1, Vdb);
-	    false -> {[],Bef}
-	end,
+    {Sis,Int0} = maybe_adjust_stack(Bef, Le#l.i, Le#l.i+1, Vdb, St0),
 
     Int1 = clear_dead(Int0, Le#l.i, Vdb),
     Reg = put_reg(V, Int1#sr.reg),
@@ -1515,8 +1512,7 @@ set_cg([{var,R}], {cons,Es}, Le, Vdb, Bef, St) ->
     Int1 = Int0#sr{reg=put_reg(R, Int0#sr.reg)},
     Ret = fetch_reg(R, Int1#sr.reg),
     {[{put_list,S1,S2,Ret}], Int1, St};
-set_cg([{var,R}], {binary,Segs}, Le, Vdb, Bef,
-       #cg{in_catch=InCatch, bfail=Bfail}=St) ->
+set_cg([{var,R}], {binary,Segs}, Le, Vdb, Bef, #cg{bfail=Bfail}=St) ->
     %% At run-time, binaries are constructed in three stages:
     %% 1) First the size of the binary is calculated.
     %% 2) Then the binary is allocated.
@@ -1535,11 +1531,7 @@ set_cg([{var,R}], {binary,Segs}, Le, Vdb, Bef,
     %% First generate the code that constructs each field.
     Fail = {f,Bfail},
     PutCode = cg_bin_put(Segs, Fail, Bef),
-    {Sis,Int1} =
-	case InCatch of
-	    true -> adjust_stack(Int0, Le#l.i, Le#l.i+1, Vdb);
-	    false -> {[],Int0}
-	end,
+    {Sis,Int1} = maybe_adjust_stack(Int0, Le#l.i, Le#l.i+1, Vdb, St),
     MaxRegs = max_reg(Bef#sr.reg),
     Aft = clear_dead(Int1, Le#l.i, Vdb),
 
@@ -1548,14 +1540,11 @@ set_cg([{var,R}], {binary,Segs}, Le, Vdb, Bef,
     {Sis++Code,Aft,St};
 % Map single variable key
 set_cg([{var,R}], {map,Op,Map,[{map_pair,{var,_}=K,V}]}, Le, Vdb, Bef,
-       #cg{in_catch=InCatch,bfail=Bfail}=St) ->
+       #cg{bfail=Bfail}=St) ->
 
     Fail = {f,Bfail},
-    {Sis,Int0} =
-	case InCatch of
-	    true -> adjust_stack(Bef, Le#l.i, Le#l.i+1, Vdb);
-	    false -> {[],Bef}
-	end,
+    {Sis,Int0} = maybe_adjust_stack(Bef, Le#l.i, Le#l.i+1, Vdb, St),
+
     SrcReg = cg_reg_arg(Map,Int0),
     Line = line(Le#l.a),
 
@@ -1576,17 +1565,13 @@ set_cg([{var,R}], {map,Op,Map,[{map_pair,{var,_}=K,V}]}, Le, Vdb, Bef,
 
 % Map (possibly) multiple literal keys
 set_cg([{var,R}], {map,Op,Map,Es}, Le, Vdb, Bef,
-       #cg{in_catch=InCatch,bfail=Bfail}=St) ->
+       #cg{bfail=Bfail}=St) ->
 
     %% assert key literals
     [] = [Var||{map_pair,{var,_}=Var,_} <- Es],
 
     Fail = {f,Bfail},
-    {Sis,Int0} =
-	case InCatch of
-	    true -> adjust_stack(Bef, Le#l.i, Le#l.i+1, Vdb);
-	    false -> {[],Bef}
-	end,
+    {Sis,Int0} = maybe_adjust_stack(Bef, Le#l.i, Le#l.i+1, Vdb, St),
     SrcReg = cg_reg_arg(Map,Int0),
     Line = line(Le#l.a),
 
@@ -2041,6 +2026,19 @@ trim_free([R|Rs0]) ->
     end;
 trim_free([]) -> [].
 
+%% maybe_adjust_stack(Bef, FirstBefore, LastFrom, Vdb, St) -> {[Ainstr],Aft}.
+%%  Adjust the stack, but only if the code is inside a catch and not
+%%  inside a guard.  Use this funtion before instructions that may
+%%  cause an exception.
+
+maybe_adjust_stack(Bef, Fb, Lf, Vdb, St) ->
+    case St of
+	#cg{in_catch=true,bfail=0} ->
+	    adjust_stack(Bef, Fb, Lf, Vdb);
+	#cg{} ->
+	    {[],Bef}
+    end.
+
 %% adjust_stack(Bef, FirstBefore, LastFrom, Vdb) -> {[Ainstr],Aft}.
 %%  Do complete stack adjustment by compressing stack and adding
 %%  variables to be saved.  Try to optimise ordering on stack by
diff --git a/lib/compiler/test/guard_SUITE.erl b/lib/compiler/test/guard_SUITE.erl
index 3f073d79cb..47eb1ba78b 100644
--- a/lib/compiler/test/guard_SUITE.erl
+++ b/lib/compiler/test/guard_SUITE.erl
@@ -34,7 +34,8 @@
 	 tricky/1,rel_ops/1,rel_op_combinations/1,literal_type_tests/1,
 	 basic_andalso_orelse/1,traverse_dcd/1,
 	 check_qlc_hrl/1,andalso_semi/1,t_tuple_size/1,binary_part/1,
-	 bad_constants/1,bad_guards/1,scotland/1]).
+	 bad_constants/1,bad_guards/1,scotland/1,
+	 guard_in_catch/1]).
 
 suite() -> [{ct_hooks,[ts_install_cth]}].
 
@@ -52,7 +53,7 @@ groups() ->
        rel_ops,rel_op_combinations,
        literal_type_tests,basic_andalso_orelse,traverse_dcd,
        check_qlc_hrl,andalso_semi,t_tuple_size,binary_part,
-       bad_constants,bad_guards,scotland]}].
+       bad_constants,bad_guards,scotland,guard_in_catch]}].
 
 init_per_suite(Config) ->
     Config.
@@ -1852,6 +1853,57 @@ do_scotland(Echo) ->
 
 found(_, _) -> million.
 
+%% Building maps in a guard in a 'catch' would crash v3_codegen.
+
+guard_in_catch(_Config) ->
+    {'EXIT',{if_clause,_}} = do_guard_in_catch_map_1(#{}),
+    {'EXIT',{if_clause,_}} = do_guard_in_catch_map_1(#{a=>b}),
+    {'EXIT',{if_clause,_}} = do_guard_in_catch_map_1(atom),
+
+    {'EXIT',{if_clause,_}} = do_guard_in_catch_map_2(#{}),
+    {'EXIT',{if_clause,_}} = do_guard_in_catch_map_2(#{a=>b}),
+    {'EXIT',{if_clause,_}} = do_guard_in_catch_map_2(atom),
+
+    {'EXIT',{if_clause,_}} = (catch do_guard_in_catch_map_3()),
+
+    {'EXIT',{if_clause,_}} = do_guard_in_catch_bin(42),
+    {'EXIT',{if_clause,_}} = do_guard_in_catch_bin(<<1,2,3>>),
+    {'EXIT',{if_clause,_}} = do_guard_in_catch_bin(atom),
+    {'EXIT',{if_clause,_}} = do_guard_in_catch_bin(#{}),
+
+    ok.
+
+do_guard_in_catch_map_1(From) ->
+    catch
+	if
+	    From#{[] => sufficient} ->
+		saint
+	end.
+
+do_guard_in_catch_map_2(From) ->
+    catch
+	if
+	    From#{From => sufficient} ->
+		saint
+	end.
+
+do_guard_in_catch_map_3() ->
+    try
+	if [] -> solo end
+    catch
+	Friendly when Friendly#{0 => []} -> minutes
+    after
+	membership
+    end.
+
+do_guard_in_catch_bin(From) ->
+    %% Would not crash v3_codegen, but there would be an unnecessary
+    %% 'move' to a Y register.
+    catch
+	if
+	    <<From:32>> ->
+		saint
+	end.
 
 
 %% Call this function to turn off constant propagation.