beam_validator: Use a record representing the match context

Using a record will make it much easier to add additional information.

1 files changed, 20 insertions, 14 deletions

diff --git a/lib/compiler/src/beam_validator.erl b/lib/compiler/src/beam_validator.erl
index 1af17dc641..1cb90a043a 100644
--- a/lib/compiler/src/beam_validator.erl
+++ b/lib/compiler/src/beam_validator.erl
@@ -161,6 +161,12 @@ validate_0(Module, [{function,Name,Ar,Entry,Code}|Fs], Ft) ->
 	 		% in the module (those that start with bs_start_match2).
 	}).
 
+%% Match state.
+-record(ms,
+	{valid=0 :: non_neg_integer(),		%Valid slots
+	 slots=0 :: non_neg_integer()		%Number of slots
+	}).
+
 validate_1(Is, Name, Arity, Entry, Ft) ->
     validate_2(labels(Is), Name, Arity, Entry, Ft).
 
@@ -274,7 +280,7 @@ valfun_1({bs_context_to_binary,Ctx}, #vst{current=#st{x=Xs}}=Vst) ->
     case Ctx of
 	{Tag,X} when Tag =:= x; Tag =:= y ->
 	    Type = case gb_trees:lookup(X, Xs) of
-		       {value,{match_context,_,_}} -> term;
+		       {value,#ms{}} -> term;
 		       _ -> get_term_type(Ctx, Vst)
 		   end,
 	    set_type_reg(Type, Ctx, Vst);
@@ -575,7 +581,7 @@ valfun_4({test,bs_start_match2,{f,Fail},Live,[Ctx,NeedSlots],Ctx}, Vst0) ->
     verify_live(Live, Vst0),
     Vst1 = prune_x_regs(Live, Vst0),
     BranchVst = case CtxType of
-		    {match_context,_,_} ->
+		    #ms{} ->
 			%% The failure branch will never be taken when Ctx
 			%% is a match context. Therefore, the type for Ctx
 			%% at the failure label must not be match_context
@@ -851,7 +857,7 @@ verify_call_args(_, 0, #vst{}) ->
 verify_call_args({f,Lbl}, Live, Vst) when is_integer(Live)->
     Verify = fun(R) ->
 		     case get_move_term_type(R, Vst) of
-			 {match_context,_,_} ->
+			 #ms{} ->
 			     verify_call_match_context(Lbl, Vst);
 			 _ ->
 			     ok
@@ -1009,7 +1015,7 @@ assert_unique_map_keys([_,_|_]=Ls) ->
 %%%
 
 bsm_match_state(Slots) ->
-    {match_context,0,Slots}.
+    #ms{slots=Slots}.
 
 bsm_validate_context(Reg, Vst) ->
     _ = bsm_get_context(Reg, Vst),
@@ -1017,7 +1023,7 @@ bsm_validate_context(Reg, Vst) ->
 
 bsm_get_context({x,X}=Reg, #vst{current=#st{x=Xs}}=_Vst) when is_integer(X) ->
     case gb_trees:lookup(X, Xs) of
-	{value,{match_context,_,_}=Ctx} -> Ctx;
+	{value,#ms{}=Ctx} -> Ctx;
 	_ -> error({no_bsm_context,Reg})
     end;
 bsm_get_context(Reg, _) -> error({bad_source,Reg}).
@@ -1029,8 +1035,8 @@ bsm_save(Reg, {atom,start}, Vst) ->
     Vst;
 bsm_save(Reg, SavePoint, Vst) ->
     case bsm_get_context(Reg, Vst) of
-	{match_context,Bits,Slots} when SavePoint < Slots ->
-	    Ctx = {match_context,Bits bor (1 bsl SavePoint),Slots},
+	#ms{valid=Bits,slots=Slots}=Ctxt0 when SavePoint < Slots ->
+	    Ctx = Ctxt0#ms{valid=Bits bor (1 bsl SavePoint),slots=Slots},
 	    set_type_reg(Ctx, Reg, Vst);
 	_ -> error({illegal_save,SavePoint})
     end.
@@ -1042,7 +1048,7 @@ bsm_restore(Reg, {atom,start}, Vst) ->
     Vst;
 bsm_restore(Reg, SavePoint, Vst) ->
     case bsm_get_context(Reg, Vst) of
-	{match_context,Bits,Slots} when SavePoint < Slots ->
+	#ms{valid=Bits,slots=Slots} when SavePoint < Slots ->
 	    case Bits band (1 bsl SavePoint) of
 		0 -> error({illegal_restore,SavePoint,not_set});
 		_ -> Vst
@@ -1123,7 +1129,7 @@ assert_term(Src, Vst) ->
 %%			Thus 'exception' is never stored as type descriptor
 %%			for a register.
 %%
-%% {match_context,_,_}	A matching context for bit syntax matching. We do allow
+%% #ms{}	        A match context for bit syntax matching. We do allow
 %%			it to moved/to from stack, but otherwise it must only
 %%			be accessed by bit syntax matching instructions.
 %%
@@ -1230,7 +1236,7 @@ get_term_type(Src, Vst) ->
 	initialized -> error({unassigned,Src});
 	{catchtag,_} -> error({catchtag,Src});
 	{trytag,_} -> error({trytag,Src});
-	{match_context,_,_} -> error({match_context,Src});
+	#ms{} -> error({match_context,Src});
 	Type -> Type
     end.
 
@@ -1382,11 +1388,11 @@ merge_types(bool, {atom,A}) ->
     merge_bool(A);
 merge_types({atom,A}, bool) ->
     merge_bool(A);
-merge_types({match_context,B0,Slots},{match_context,B1,Slots}) ->
-    {match_context,B0 bor B1,Slots};
-merge_types({match_context,_,_}=M, _) ->
+merge_types(#ms{valid=B0,slots=Slots}=M,#ms{valid=B1,slots=Slots}) ->
+    M#ms{valid=B0 bor B1,slots=Slots};
+merge_types(#ms{}=M, _) ->
     M;
-merge_types(_, {match_context,_,_}=M) ->
+merge_types(_, #ms{}=M) ->
     M;
 merge_types(T1, T2) when T1 =/= T2 ->
     %% Too different. All we know is that the type is a 'term'.