[m-dev.] for review: fix lambda bug

[Fergus Henderson]

I will go ahead and commit this.

On 04-Sep-1999, Fergus Henderson <fjh at cs.mu.OZ.AU> wrote:
> Hi,
> 
> Zoltan, could you please review this one?
> 
> ----------
> 
> Estimated hours taken: 4
> 
> compiler/lambda.m:
> 	Fix a bug: when adding extra type_infos need for lambda procs,
> 	we need to add extra type_infos for the lambda parameters too,
> 	not just for the the lambda goal's non-locals.
> 	This bug caused an internal compiler error when compiling
> 	extras/trailed_update/tests/var_test.m.
> 
> diff -u -r1.55 lambda.m
> --- compiler/lambda.m	1999/08/13 01:43:03	1.55
> +++ compiler/lambda.m	1999/09/03 19:29:31
> @@ -313,34 +305,12 @@
>  	% (see the documentation at top of this file)
>  	ExistQVars = [],
>  	LambdaGoal = _ - LambdaGoalInfo,
> -	goal_info_get_nonlocals(LambdaGoalInfo, LambdaNonLocals),
> +	goal_info_get_nonlocals(LambdaGoalInfo, LambdaGoalNonLocals),
> +	set__insert_list(LambdaGoalNonLocals, Vars, LambdaNonLocals),
>  	goal_util__extra_nonlocal_typeinfos(TVarMap, TCVarMap, VarTypes,
>  		ExistQVars, LambdaNonLocals, ExtraTypeInfos),
> 
> ----------
> 
> Estimated hours taken: 0.5
> 
> compiler/lambda.m:
> 	Clean up the code a bit: lambda__transform_lambda does not
> 	need to be exported, since it isn't used elsewhere, and the
> 	code is in fact clearer if it is manually inlined into its
> 	caller (lambda__process_lambda).
> 
> Workspace: /usr/hg2/fjh/mercury
> Index: compiler/lambda.m
> ===================================================================
> RCS file: /home/mercury1/repository/mercury/compiler/lambda.m,v
> retrieving revision 1.55
> diff -u -r1.55 lambda.m
> --- compiler/lambda.m	1999/08/13 01:43:03	1.55
> +++ compiler/lambda.m	1999/09/03 19:29:31
> @@ -69,8 +69,7 @@
>  
>  :- interface. 
>  
> -:- import_module hlds_module, hlds_pred, hlds_goal, prog_data.
> -:- import_module list, map, set.
> +:- import_module hlds_module, hlds_pred.
>  
>  :- pred lambda__process_module(module_info, module_info).
>  :- mode lambda__process_module(in, out) is det.
> @@ -78,24 +77,16 @@
>  :- pred lambda__process_pred(pred_id, module_info, module_info).
>  :- mode lambda__process_pred(in, in, out) is det.
>  
> -:- pred lambda__transform_lambda(pred_or_func, lambda_eval_method, string,
> -		list(prog_var), list(mode), determinism, list(prog_var),
> -		set(prog_var), hlds_goal, unification, prog_varset,
> -		map(prog_var, type), class_constraints, tvarset,
> -		map(tvar, type_info_locn), map(class_constraint, prog_var),
> -		pred_markers, aditi_owner, module_info, unify_rhs,
> -		unification, module_info).
> -:- mode lambda__transform_lambda(in, in, in, in, in, in, in, in, in, in,
> -		in, in, in, in, in, in, in, in, in, out, out, out) is det.
> -
>  %-----------------------------------------------------------------------------%
>  %-----------------------------------------------------------------------------%
>  
>  :- implementation.
>  
> +:- import_module hlds_goal, prog_data.
>  :- import_module hlds_data, make_hlds, globals, options, type_util.
>  :- import_module goal_util, prog_util, mode_util, inst_match, llds, arg_info.
>  
> +:- import_module list, map, set.
>  :- import_module term, varset, bool, string, std_util, require.
>  
>  :- type lambda_info --->
> @@ -291,11 +282,12 @@
>  :- mode lambda__process_lambda(in, in, in, in, in, in, in, in, out, out,
>  		in, out) is det.
>  
> -lambda__process_lambda(PredOrFunc, EvalMethod, Vars, Modes, Det,
> +lambda__process_lambda(PredOrFunc, EvalMethod, Vars, Modes, Detism,
>  		OrigNonLocals0, LambdaGoal, Unification0, Functor,
>  		Unification, LambdaInfo0, LambdaInfo) :-
>  	LambdaInfo0 = lambda_info(VarSet, VarTypes, _PredConstraints, TVarSet,
> -		TVarMap, TCVarMap, Markers, POF, PredName, Owner, ModuleInfo0),
> +		TVarMap, TCVarMap, Markers, POF, OrigPredName, Owner,
> +		ModuleInfo0),
>  
>  		% Calculate the constraints which apply to this lambda
>  		% expression. 
> @@ -313,34 +305,12 @@
>  	% (see the documentation at top of this file)
>  	ExistQVars = [],
>  	LambdaGoal = _ - LambdaGoalInfo,
> -	goal_info_get_nonlocals(LambdaGoalInfo, LambdaNonLocals),
> +	goal_info_get_nonlocals(LambdaGoalInfo, LambdaGoalNonLocals),
> +	set__insert_list(LambdaGoalNonLocals, Vars, LambdaNonLocals),
>  	goal_util__extra_nonlocal_typeinfos(TVarMap, TCVarMap, VarTypes,
>  		ExistQVars, LambdaNonLocals, ExtraTypeInfos),
> -	lambda__transform_lambda(PredOrFunc, EvalMethod, PredName, Vars, Modes,
> -		Det, OrigNonLocals0, ExtraTypeInfos, LambdaGoal, Unification0,
> -		VarSet, VarTypes, Constraints, TVarSet, TVarMap, TCVarMap,
> -		Markers, Owner, ModuleInfo0, Functor, Unification, ModuleInfo),
> -	LambdaInfo = lambda_info(VarSet, VarTypes, Constraints, TVarSet,
> -		TVarMap, TCVarMap, Markers, POF, PredName, Owner, ModuleInfo).
> -
> -:- pred lambda__constraint_contains_vars(list(tvar), class_constraint).
> -:- mode lambda__constraint_contains_vars(in, in) is semidet.
> -
> -lambda__constraint_contains_vars(LambdaVars, ClassConstraint) :-
> -	ClassConstraint = constraint(_, ConstraintTypes),
> -	list__map(type_util__vars, ConstraintTypes, ConstraintVarsList),
> -	list__condense(ConstraintVarsList, ConstraintVars),
> -		% Probably not the most efficient way of doing it, but I
> -		% wouldn't think that it matters.
> -	set__list_to_set(LambdaVars, LambdaVarsSet),
> -	set__list_to_set(ConstraintVars, ConstraintVarsSet),
> -	set__subset(ConstraintVarsSet, LambdaVarsSet).
> +	OrigVars = OrigNonLocals0,
>  
> -lambda__transform_lambda(PredOrFunc, EvalMethod, OrigPredName, Vars, Modes,
> -		Detism, OrigVars, ExtraTypeInfos, LambdaGoal, Unification0,
> -		VarSet, VarTypes, Constraints, TVarSet, TVarMap, TCVarMap,
> -		Markers, Owner, ModuleInfo0, Functor,
> -		Unification, ModuleInfo) :-
>  	(
>  		Unification0 = construct(Var0, _, _, UniModes0, _, _, _)
>  	->
> @@ -350,26 +320,26 @@
>  		error("lambda__transform_lambda: weird unification")
>  	),
>  
> -	% Optimize a special case: replace
> -	%	`lambda([Y1, Y2, ...] is Detism, p(X1, X2, ..., Y1, Y2, ...))'
> -	% where `p' has determinism `Detism' with
> -	%	`p(X1, X2, ...)'
> -	%
> -	% This optimization is only valid if the modes of the Xi are
> -	% input, since only input arguments can be curried.
> -	% It's also only valid if all the inputs in the Yi precede the
> -	% outputs.  It's also not valid if any of the Xi are in the Yi.
> +	set__delete_list(LambdaGoalNonLocals, Vars, NonLocals1),
>  
> -	LambdaGoal = _ - LambdaGoalInfo,
> -	goal_info_get_nonlocals(LambdaGoalInfo, NonLocals0),
> -	set__delete_list(NonLocals0, Vars, NonLocals1),
> -
>  	% We need all the typeinfos, including the ones that are not used,
>  	% for the layout structure describing the closure.
>  	set__union(NonLocals1, ExtraTypeInfos, NonLocals),
>  
>  	set__to_sorted_list(NonLocals, ArgVars1),
> +
>  	( 
> +		% Optimize a special case: replace
> +		%	`lambda([Y1, Y2, ...] is Detism,
> +		%		p(X1, X2, ..., Y1, Y2, ...))'
> +		% where `p' has determinism `Detism' with
> +		%	`p(X1, X2, ...)'
> +		%
> +		% This optimization is only valid if the modes of the Xi are
> +		% input, since only input arguments can be curried.
> +		% It's also only valid if all the inputs in the Yi precede the
> +		% outputs.  It's also not valid if any of the Xi are in the Yi.
> +
>  		LambdaGoal = call(PredId0, ProcId0, CallVars,
>  					_, _, PredName0) - _,
>  		module_info_pred_proc_info(ModuleInfo0, PredId0, ProcId0,
> @@ -441,7 +411,7 @@
>  		goal_info_get_context(LambdaGoalInfo, LambdaContext),
>  		% The TVarSet is a superset of what it really ought be,
>  		% but that shouldn't matter.
> -		% XXX existentially typed lambda expressions are not
> +		% Existentially typed lambda expressions are not
>  		% yet supported (see the documentation at top of this file)
>  		ExistQVars = [],
>  		lambda__uni_modes_to_modes(UniModes1, OrigArgModes),
> @@ -542,7 +512,23 @@
>  	VarToReuse = no,
>  	RLExprnId = no,
>  	Unification = construct(Var, ConsId, ArgVars, UniModes,
> -		VarToReuse, cell_is_unique, RLExprnId).
> +		VarToReuse, cell_is_unique, RLExprnId),
> +	LambdaInfo = lambda_info(VarSet, VarTypes, Constraints, TVarSet,
> +		TVarMap, TCVarMap, Markers, POF, OrigPredName, Owner,
> +		ModuleInfo).
> +
> +:- pred lambda__constraint_contains_vars(list(tvar), class_constraint).
> +:- mode lambda__constraint_contains_vars(in, in) is semidet.
> +
> +lambda__constraint_contains_vars(LambdaVars, ClassConstraint) :-
> +	ClassConstraint = constraint(_, ConstraintTypes),
> +	list__map(type_util__vars, ConstraintTypes, ConstraintVarsList),
> +	list__condense(ConstraintVarsList, ConstraintVars),
> +		% Probably not the most efficient way of doing it, but I
> +		% wouldn't think that it matters.
> +	set__list_to_set(LambdaVars, LambdaVarsSet),
> +	set__list_to_set(ConstraintVars, ConstraintVarsSet),
> +	set__subset(ConstraintVarsSet, LambdaVarsSet).
>  
>  :- pred lambda__uni_modes_to_modes(list(uni_mode), list(mode)).
>  :- mode lambda__uni_modes_to_modes(in, out) is det.

-- 
Fergus Henderson <fjh at cs.mu.oz.au>  |  "I have always known that the pursuit
WWW: <http://www.cs.mu.oz.au/~fjh>  |  of excellence is a lethal habit"
PGP: finger fjh at 128.250.37.3        |     -- the last words of T. S. Garp.
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