Merge branch 'bg/compiler-bopt-bug' into ccase/r13b04_dev

* bg/compiler-bopt-bug:
  beam_bool: Fix generation of code that does not validate
  Fix crash in beam_bool

OTP-8338  Using complex boolean expressions in ifs could cause the compiler
          to either crash or teminate with an internal error. (Thanks to
          Simon Cornish.)

2 files changed, 79 insertions, 14 deletions

diff --git a/lib/compiler/src/beam_bool.erl b/lib/compiler/src/beam_bool.erl
index d8c201a194..dcc6ad4c7c 100644
--- a/lib/compiler/src/beam_bool.erl
+++ b/lib/compiler/src/beam_bool.erl
@@ -123,6 +123,12 @@ bopt_block(Reg, Fail, OldIs, [{block,Bl0}|Acc0], St0) ->
 		throw:mixed ->
 		    failed;
 
+		%% There was a reference to a boolean expression
+		%% from inside a protected block (try/catch), to
+		%% a boolean expression outside.
+		  throw:protected_barrier ->
+		    failed;
+
 		  %% The 'xor' operator was used. We currently don't
 		  %% find it worthwile to translate 'xor' operators
 		  %% (the code would be clumsy).
@@ -167,7 +173,7 @@ bopt_block(Reg, Fail, OldIs, [{block,Bl0}|Acc0], St0) ->
 %%  whether the optimized code is guaranteed to work in the same
 %%  way as the original code.
 %%
-%%  Throws an exception if the optmization is not safe.
+%%  Throw an exception if the optimization is not safe.
 %%
 ensure_opt_safe(Bl, NewCode, OldIs, Fail, PreceedingCode, St) ->
     %% Here are the conditions that must be true for the
@@ -184,10 +190,10 @@ ensure_opt_safe(Bl, NewCode, OldIs, Fail, PreceedingCode, St) ->
     %%    by the code that follows.
     %%
     %% 3. Any register that is assigned a value in the optimized
-    %%    code must be UNUSED or KILLED in the following code.
-    %%    (Possible future improvement: Registers that are known
-    %%    to be assigned the SAME value in the original and optimized
-    %%    code don't need to be unused in the following code.)
+    %%    code must be UNUSED or KILLED in the following code
+    %%    (because the register might be assigned the wrong value,
+    %%    and even if the value is right it might no longer be
+    %%    assigned on *all* paths leading to its use).
 
     InitInPreceeding = initialized_regs(PreceedingCode),
 
@@ -304,6 +310,8 @@ dst_regs([{set,[D],_,{bif,_,{f,_}}}|Is], Acc) ->
     dst_regs(Is, [D|Acc]);
 dst_regs([{set,[D],_,{alloc,_,{gc_bif,_,{f,_}}}}|Is], Acc) ->
     dst_regs(Is, [D|Acc]);
+dst_regs([{set,[D],_,move}|Is], Acc) ->
+    dst_regs(Is, [D|Acc]);
 dst_regs([_|Is], Acc) ->
     dst_regs(Is, Acc);
 dst_regs([], Acc) -> ordsets:from_list(Acc).
@@ -414,11 +422,10 @@ bopt_good_args([A|As], Regs) ->
 bopt_good_args([], _) -> ok.
 
 bopt_good_arg({Tag,_}=X, Regs) when Tag =:= x; Tag =:= tmp ->
-    case gb_trees:get(X, Regs) of
-	any -> ok;
-	_Other ->
-	    %%io:format("not any: ~p: ~p\n", [X,_Other]),
-	    throw(mixed)
+    case gb_trees:lookup(X, Regs) of
+	{value,any} -> ok;
+	{value,_} -> throw(mixed);
+	none -> throw(protected_barrier)
     end;
 bopt_good_arg(_, _) -> ok.
 
diff --git a/lib/compiler/test/andor_SUITE.erl b/lib/compiler/test/andor_SUITE.erl
index 34609a49f2..a460d54239 100644
--- a/lib/compiler/test/andor_SUITE.erl
+++ b/lib/compiler/test/andor_SUITE.erl
@@ -20,13 +20,14 @@
 
 -export([all/1,
 	 t_case/1,t_and_or/1,t_andalso/1,t_orelse/1,inside/1,overlap/1,
-	 combined/1,in_case/1]).
+	 combined/1,in_case/1,before_and_inside_if/1]).
 	 
 -include("test_server.hrl").
 
 all(suite) ->
     test_lib:recompile(?MODULE),
-    [t_case,t_and_or,t_andalso,t_orelse,inside,overlap,combined,in_case].
+    [t_case,t_and_or,t_andalso,t_orelse,inside,overlap,combined,in_case,
+     before_and_inside_if].
 
 t_case(Config) when is_list(Config) ->
     %% We test boolean cases almost but not quite like cases
@@ -380,6 +381,65 @@ in_case_1_guard(LenUp, LenDw, LenN, Rotation, Count) ->
 	false -> loop
     end.
 
+before_and_inside_if(Config) when is_list(Config) ->
+    ?line no = before_and_inside_if([a], [b], delete),
+    ?line no = before_and_inside_if([a], [b], x),
+    ?line no = before_and_inside_if([a], [], delete),
+    ?line no = before_and_inside_if([a], [], x),
+    ?line no = before_and_inside_if([], [], delete),
+    ?line yes = before_and_inside_if([], [], x),
+    ?line yes = before_and_inside_if([], [b], delete),
+    ?line yes = before_and_inside_if([], [b], x),
+
+    ?line {ch1,ch2} = before_and_inside_if_2([a], [b], blah),
+    ?line {ch1,ch2} = before_and_inside_if_2([a], [b], xx),
+    ?line {ch1,ch2} = before_and_inside_if_2([a], [], blah),
+    ?line {ch1,ch2} = before_and_inside_if_2([a], [], xx),
+    ?line {no,no} = before_and_inside_if_2([], [b], blah),
+    ?line {no,no} = before_and_inside_if_2([], [b], xx),
+    ?line {ch1,no} = before_and_inside_if_2([], [], blah),
+    ?line {no,ch2} = before_and_inside_if_2([], [], xx),
+    ok.
+
+%% Thanks to Simon Cornish and Kostis Sagonas.
+%% Used to crash beam_bool.
+before_and_inside_if(XDo1, XDo2, Do3) ->
+    Do1 = (XDo1 =/= []),
+    Do2 = (XDo2 =/= []),
+    if
+	%% This expression occurs in a try/catch (protected)
+	%% block, which cannot refer to variables outside of
+	%% the block that are boolean expressions.
+	Do1 =:= true;
+	Do1 =:= false, Do2 =:= false, Do3 =:= delete ->
+	    no;
+       true ->
+	    yes
+    end.
+
+%% Thanks to Simon Cornish.
+%% Used to generate code that would not set {y,0} on
+%% all paths before its use (and therefore fail
+%% validation by the beam_validator).
+before_and_inside_if_2(XDo1, XDo2, Do3) ->
+    Do1    = (XDo1 =/= []),
+    Do2    = (XDo2 =/= []),
+    CH1 = if Do1 == true;
+	     Do1 == false,Do2==false,Do3 == blah ->
+		  ch1;
+	     true ->
+		  no
+	  end,
+    CH2 = if Do1 == true;
+	     Do1 == false,Do2==false,Do3 == xx ->
+		  ch2;
+	     true ->
+		  no
+	  end,
+    {CH1,CH2}.
+
+%% Utilities.
+
 check(V1, V0) ->
     if V1 /= V0 ->
 	    io:fwrite("error: ~w.\n", [V1]),
@@ -393,5 +453,3 @@ echo(X) ->
     X.
 
 id(I) -> I.
-
-