[m-dev.] diff: accurate gc typeinfo variable bug.

[Tyson Richard DOWD]

> Tyson Richard DOWD, you wrote:
> > 
> > 	Fergus, can you please review this?
> 
> > +		% If a variable is unused in the goal, it shouldn't be
> > +		% in the initial liveness. (If we allowed it to start
> > +		% live, it wouldn't ever become dead, because it would
> > +		% have to be used to be killed).
> > +		% So we intersect the headvars with the non-locals.
> > +	proc_info_goal(ProcInfo, _Goal - GoalInfo),
> > +	goal_info_get_nonlocals(GoalInfo, NonLocals),
> > +	set__intersect(Liveness2, NonLocals, Liveness3),
> > +		% If doing accurate garbage collection, the corresponding
> > +		% typeinfos need to be added to these.
> > +	module_info_globals(ModuleInfo, Globals),
> > +	globals__get_gc_method(Globals, GCmethod),
> > +	(
> > +		GCmethod = accurate
> > +	->
> > +		proc_info_get_typeinfo_vars_setwise(ProcInfo, Liveness3,
> > +			TypeInfoVars),
> > +		set__union(Liveness3, TypeInfoVars, Liveness)
> > +	;
> > +		Liveness = Liveness3
> 
> Are you sure that these two steps are done in the right order?
> Shouldn't the typeinfo vars be intersected with the non-locals too?

Although for the particular problem I was trying to solve, it wouldn't
matter, in general I think you are right. I'll do it that way.

Also, I attached the wrong diff to the mail (the changes to liveness.m
were part of the code I intended Tom to review). I meant to ask you to
review these changes to polymorphism...

===================================================================

Estimated hours taken: 10

Fix a bug in compilation in accurate GC grades.

compiler/polymorphism.m:
	Add any introduced typeinfo variables to the typevar map.
	Without this unbound type variables won't not occur in the 
	typevar map, and the liveness calculations won't be able to
	make sure the typeinfos for the unbound type variables are
	kept live when they should be. (that is, the map lookups would
	fail looking in the typevar map).

Index: polymorphism.m
===================================================================
RCS file: /home/staff/zs/imp/mercury/compiler/polymorphism.m,v
retrieving revision 1.103
diff -u -r1.103 polymorphism.m
--- polymorphism.m	1997/05/05 11:17:24	1.103
+++ polymorphism.m	1997/05/08 06:49:27
@@ -665,7 +665,7 @@
 polymorphism__process_call(PredId, _ProcId, ArgVars0, ArgVars,
 				ExtraVars, ExtraGoals, Info0, Info) :-
 	Info0 = poly_info(VarSet0, VarTypes0, TypeVarSet0,
-				TypeInfoMap, ModuleInfo),
+				TypeInfoMap0, ModuleInfo),
 	module_info_pred_info(ModuleInfo, PredId, PredInfo),
 	pred_info_arg_types(PredInfo, PredTypeVarSet, PredArgTypes0),
 		% rename apart
@@ -691,9 +691,10 @@
 		term__var_list_to_term_list(PredTypeVars, PredTypes0),
 		term__apply_rec_substitution_to_list(PredTypes0, TypeSubst,
 			PredTypes),
-		polymorphism__make_vars(PredTypes, ModuleInfo, TypeInfoMap,
+		polymorphism__make_vars(PredTypes, ModuleInfo, TypeInfoMap0,
 				VarSet0, VarTypes0,
-				ExtraVars, ExtraGoals, VarSet, VarTypes),
+				ExtraVars, TypeInfoMap, ExtraGoals, VarSet, 
+				VarTypes),
 		list__append(ExtraVars, ArgVars0, ArgVars),
 		Info = poly_info(VarSet, VarTypes, TypeVarSet,
 				TypeInfoMap, ModuleInfo)
@@ -749,27 +750,33 @@
 % Update the varset and vartypes accordingly.
 
 :- pred polymorphism__make_vars(list(type), module_info, map(tvar, var),
-	varset, map(var, type), list(var), list(hlds_goal),
+	varset, map(var, type), list(var), map(tvar, var), list(hlds_goal),
 	varset, map(var, type)).
-:- mode polymorphism__make_vars(in, in, in, in, in, out, out, out, out) is det.
+:- mode polymorphism__make_vars(in, in, in, in, in, out, out, out, out, 
+	out) is det.
 
-polymorphism__make_vars([], _, _, VarSet, VarTypes, [], [], VarSet, VarTypes).
-polymorphism__make_vars([Type | Types], ModuleInfo, TypeInfoMap,
-		VarSet0, VarTypes0, ExtraVars, ExtraGoals, VarSet, VarTypes) :-
-	polymorphism__make_var(Type, ModuleInfo, TypeInfoMap,
-		VarSet0, VarTypes0, Var, ExtraGoals1, VarSet1, VarTypes1),
-	polymorphism__make_vars(Types, ModuleInfo, TypeInfoMap,
-		VarSet1, VarTypes1, ExtraVars2, ExtraGoals2, VarSet, VarTypes),
+polymorphism__make_vars([], _, TypeInfoMap, VarSet, VarTypes, [], TypeInfoMap,
+		[], VarSet, VarTypes).
+polymorphism__make_vars([Type | Types], ModuleInfo, TypeInfoMap0,
+		VarSet0, VarTypes0, ExtraVars, TypeInfoMap, ExtraGoals, 
+		VarSet, VarTypes) :-
+	polymorphism__make_var(Type, ModuleInfo, TypeInfoMap0,
+		VarSet0, VarTypes0, Var, TypeInfoMap1, ExtraGoals1, VarSet1,
+		VarTypes1),
+	polymorphism__make_vars(Types, ModuleInfo, TypeInfoMap1,
+		VarSet1, VarTypes1, ExtraVars2, TypeInfoMap, ExtraGoals2, 
+		VarSet, VarTypes),
 	ExtraVars = [Var | ExtraVars2],
 	list__append(ExtraGoals1, ExtraGoals2, ExtraGoals).
 
-:- pred polymorphism__make_var(type, module_info, map(tvar, var),
-	varset, map(var, type), var, list(hlds_goal),
+:- pred polymorphism__make_var(type, module_info, map(tvar, var), 
+	varset, map(var, type), var, map(tvar, var), list(hlds_goal),
 	varset, map(var, type)).
-:- mode polymorphism__make_var(in, in, in, in, in, out, out, out, out) is det.
+:- mode polymorphism__make_var(in, in, in, in, in, out, out, out, out, out) 
+	is det.
 
-polymorphism__make_var(Type, ModuleInfo, TypeInfoMap,
-		VarSet0, VarTypes0, Var, ExtraGoals, VarSet, VarTypes) :-
+polymorphism__make_var(Type, ModuleInfo, TypeInfoMap0, VarSet0, VarTypes0, 
+		Var, TypeInfoMap, ExtraGoals, VarSet, VarTypes) :-
 	(
 		type_is_higher_order(Type, _PredOrFunc, TypeArgs)
 	->
@@ -785,8 +792,8 @@
 		% the type_info of higher-order types.
 		TypeId = unqualified("pred") - 0,
 		polymorphism__construct_type_info(Type, TypeId, TypeArgs,
-			yes, ModuleInfo, TypeInfoMap, VarSet0, VarTypes0,
-			Var, ExtraGoals, VarSet, VarTypes)
+			yes, ModuleInfo, TypeInfoMap0, VarSet0, VarTypes0,
+			Var, TypeInfoMap, ExtraGoals, VarSet, VarTypes)
 	;
 		type_to_type_id(Type, TypeId, TypeArgs)
 	->
@@ -796,11 +803,11 @@
 		% at the top of the module.
 
 		polymorphism__construct_type_info(Type, TypeId, TypeArgs,
-			no, ModuleInfo, TypeInfoMap, VarSet0, VarTypes0,
-			Var, ExtraGoals, VarSet, VarTypes)
+			no, ModuleInfo, TypeInfoMap0, VarSet0, VarTypes0,
+			Var, TypeInfoMap, ExtraGoals, VarSet, VarTypes)
 	;
 		Type = term__variable(TypeVar1),
-		map__search(TypeInfoMap, TypeVar1, TypeInfoVar)
+		map__search(TypeInfoMap0, TypeVar1, TypeInfoVar)
 	->
 		% This occurs for code where a predicate calls a polymorphic
 		% predicate with a bound but unknown value of the type variable.
@@ -821,8 +828,11 @@
 		Var = TypeInfoVar,
 		ExtraGoals = [],
 		VarSet = VarSet0,
-		VarTypes = VarTypes0
+		VarTypes = VarTypes0,
+		TypeInfoMap = TypeInfoMap0
 	;
+		Type = term__variable(TypeVar1)
+	->
 		% This occurs for code where a predicate calls a polymorphic
 		% predicate with an unbound type variable, for example
 		%
@@ -854,24 +864,27 @@
 		% variable to zero
 		TypeId = unqualified("void") - 0,
 		polymorphism__construct_type_info(Type, TypeId, [],
-			no, ModuleInfo, TypeInfoMap, VarSet0, VarTypes0,
-			Var, ExtraGoals, VarSet, VarTypes)
+			no, ModuleInfo, TypeInfoMap0, VarSet0, VarTypes0,
+			Var, TypeInfoMap1, ExtraGoals, VarSet, VarTypes),
+		map__det_insert(TypeInfoMap1, TypeVar1, Var, TypeInfoMap)
+	;
+		error("polymorphism__make_var: unknown type")
 	).
 
 :- pred polymorphism__construct_type_info(type, type_id, list(type),
 	bool, module_info, map(tvar, var), varset, map(var, type),
-	var, list(hlds_goal), varset, map(var, type)).
+	var, map(tvar, var), list(hlds_goal), varset, map(var, type)).
 :- mode polymorphism__construct_type_info(in, in, in, in, in, in, in, in,
-	out, out, out, out) is det.
+	out, out, out, out, out) is det.
 
 polymorphism__construct_type_info(Type, TypeId, TypeArgs, IsHigherOrder, 
-		ModuleInfo, TypeInfoMap, VarSet0, VarTypes0,
-		Var, ExtraGoals, VarSet, VarTypes) :-
+		ModuleInfo, TypeInfoMap0, VarSet0, VarTypes0,
+		Var, TypeInfoMap, ExtraGoals, VarSet, VarTypes) :-
 
 	% Create the typeinfo vars for the arguments
-	polymorphism__make_vars(TypeArgs, ModuleInfo, TypeInfoMap,
-		VarSet0, VarTypes0, ArgTypeInfoVars, ArgTypeInfoGoals,
-		VarSet1, VarTypes1),
+	polymorphism__make_vars(TypeArgs, ModuleInfo, TypeInfoMap0,
+		VarSet0, VarTypes0, ArgTypeInfoVars, TypeInfoMap, 
+		ArgTypeInfoGoals, VarSet1, VarTypes1),
 
 	module_info_globals(ModuleInfo, Globals),
 	globals__get_type_info_method(Globals, TypeInfoMethod),


-- 
       Tyson Dowd           #
                            #             Sign on refrigerator:
     trd at cs.mu.oz.au        #           Refrigerate after opening. 
http://www.cs.mu.oz.au/~trd #                  - C. J. Owen.