[m-rev.] [reuse] diff: keeping potential_reuse information

[Nancy Mazur]

Hi,


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


Estimated hours taken: 2
Branches: reuse

Extend the reuse_goal_info with a new functor: potential_reuse/1. This
is equivalent to reuse/1. Yet, insteaf of generating reuse information
during the choice (sr_choice) and indirect reuse passes (sr_indirect), 
we now generate potential_reuse information. This allows to split 
procedures into reuse versions, yet keeping all the interesting reuse-related
information (lfu, lbu, dead deconstructs which lead to no reuse) within
the basic no-reuse version. This is a first step into diagnosing what
goes on when no reuse is allowed. 
(In a second step, I'll be adding a full reuse-assignment pass based 
on a kindof matching-solving algorithm. Diagnoses will be different, but
at least it'll be possible to start comparing). 

hlds_out.m:
	Consider potential_reuse as possible reuse information. 
	Reorder some of the code. 

sr_choice.m:
sr_indirect.m:
	Instead of directly generating reuse/1, generate potential_reuse/1.

sr_data.m:
	Extend the reuse_goal_info type with potential_reuse/1.

sr_split.m:
	When splitting procedures into their reuse/no-reuse versions
	we now proceed by running over the hlds_goal of the reuse version
	and substituting all potential_reuse/1 by reuse/1. 
	The basic no-reuse versions are then simply those versions
	with possibly potential_reuse/1 annotations, instead of the
	plain clean procedures as they were before reuse analysis. 
	This allows to check what is going on, even for procedures
	which do not have any reuse. 

structure_reuse.m:
	No reference to the HLDS as it was before reuse analysis is needed
	when splitting the procedures. 



Index: hlds_out.m
===================================================================
RCS file: /home/mercury1/repository/mercury/compiler/hlds_out.m,v
retrieving revision 1.243.2.20
diff -u -r1.243.2.20 hlds_out.m
--- hlds_out.m	2001/04/20 15:22:20	1.243.2.20
+++ hlds_out.m	2001/06/22 14:22:29
@@ -1162,27 +1162,40 @@
 		{ set__to_sorted_list(LFU, LFU_list) },
 			hlds_out__write_indent(Indent),
 			io__write_string("% lfu: "),
-			mercury_output_vars(LFU_list, VarSet,
+			mercury_output_vars(LFU_list, VarSet, 
 				AppendVarnums),
 			io__write_string("\n"),
 
 		{ goal_info_get_reuse(GoalInfo, REUSE) } ,
 	        (
-			{ REUSE = reuse(no_reuse) ; REUSE = empty }
+			{ REUSE = potential_reuse(no_reuse); 
+			  REUSE = reuse(no_reuse) ; 
+			  REUSE = empty }
 		->
 			[]
 		; 
-			hlds_out__write_indent(Indent),
-			io__write_string("% reuse: "),
+			{ REUSE = potential_reuse(SR) ; REUSE = reuse(SR) }
+		-> 
+			hlds_out__write_indent(Indent), 
+			io__write_string("% reuse"),
+			( 
+				{ REUSE = potential_reuse(_) }
+			-> 
+				io__write_string(" (potential)")
+			;	
+				[]
+			),
+			io__write_string(": "),
 			(
-				{ REUSE = reuse(cell_died) }
-			->
+				{ SR = no_reuse },
+				io__write_string("nothing.\n")
+			;
+				{ SR = cell_died },
 				io__write_string("cell just died (deconstruction).\n") 
 			;
-				{ REUSE = reuse(cell_reused(ProgVar,
+				{ SR = cell_reused(ProgVar,
 						IntroducesCondition,
-						ConsIds, _ReuseFields)) }
-			->
+						ConsIds, _ReuseFields) },
 				io__write_string("cell "),
 				mercury_output_var(ProgVar, VarSet, 
 					AppendVarnums),
@@ -1198,9 +1211,7 @@
 				),
 				io__nl
 			;
-				{ REUSE = reuse(
-					reuse_call(IntroducesCondition)) }
-			->
+				{ SR = reuse_call(IntroducesCondition) },
 				( { IntroducesCondition = yes } ->
 					io__write_string("Conditional ")
 				;
@@ -1208,13 +1219,12 @@
 				),
 				io__write_string("call to procedure with reuse.\n")
 			;
-				{ REUSE = reuse(missed_reuse_call(Causes)) } 
-			->
+				{ SR = missed_reuse_call(Causes) } ,
 				io__write_string("failed reuse call:\n"),
 				write_missed_reuse_call_text(Indent,Causes)
-			;
-				{ require__error("Not a legal alternative for short_reuse_info at this stage.\n") }
 			)
+		;
+			[]
 		),
 
 		{ goal_info_get_lbu(GoalInfo, Lbu) },
Index: sr_choice.m
===================================================================
RCS file: /home/mercury1/repository/mercury/compiler/Attic/sr_choice.m,v
retrieving revision 1.1.2.21
diff -u -r1.1.2.21 sr_choice.m
--- sr_choice.m	2001/04/23 12:34:45	1.1.2.21
+++ sr_choice.m	2001/06/22 14:23:22
@@ -690,7 +690,8 @@
 			ConditionalReuse = yes
 		},
 		{ goal_info_set_reuse(GoalInfo0,
-				reuse(cell_reused(ReuseVar, ConditionalReuse,
+				potential_reuse(cell_reused(ReuseVar, 
+						ConditionalReuse,
 						ConsIds, ReuseFields)),
 				GoalInfo) },
 		ReuseConditions =^ reuse_conds,
@@ -698,7 +699,7 @@
 	;
 		{ LocalReused = LocalReused0 },
 		{ goal_info_set_reuse(GoalInfo0,
-				reuse(no_reuse),
+				potential_reuse(no_reuse),
 				GoalInfo) }
 	),
 	^ local_used := LocalReused.
@@ -812,7 +813,8 @@
 	{ ReuseInfo = choice(deconstruct(MaybeDies)) ->
 		(
 			MaybeDies = yes(Condition),
-			goal_info_set_reuse(GoalInfo0, reuse(cell_died),
+			goal_info_set_reuse(GoalInfo0, 
+					potential_reuse(cell_died),
 					GoalInfo),
 			( set__member(Var, ReusedVars) ->
 				CanCGC = no
@@ -832,7 +834,8 @@
 		;
 			MaybeDies = no,
 			CanCGC = no,
-			goal_info_set_reuse(GoalInfo0, reuse(no_reuse),
+			goal_info_set_reuse(GoalInfo0, 
+					potential_reuse(no_reuse),
 					GoalInfo)
 		)
 	;
Index: sr_data.m
===================================================================
RCS file: /home/mercury1/repository/mercury/compiler/Attic/sr_data.m,v
retrieving revision 1.1.2.17
diff -u -r1.1.2.17 sr_data.m
--- sr_data.m	2001/03/16 09:09:56	1.1.2.17
+++ sr_data.m	2001/06/22 14:23:22
@@ -24,10 +24,14 @@
 	% structure reuse.
 	% This field should be initilaised to empty.
 	% The sr_dead module replaces empty with choice.
-	% The sr_choice module replaces choice with reuse.
+	% The sr_choice&sr_indirect module replaces choice with 
+	% 	potential_reuse.
+	% The sr_split module replaces potential_reuse with reuse for
+	% 	the reuse-version of a procedure. 
 :- type reuse_goal_info
 	--->	empty
 	;	choice(choice_info)
+	; 	potential_reuse(short_reuse_info)
 	;	reuse(short_reuse_info).
 
 :- type short_reuse_info --->
@@ -92,6 +96,13 @@
 
 :- type memo_reuse == maybe(list(reuse_condition)).
 
+
+%-----------------------------------------------------------------------------%
+% small predicates for manipulating/transforming reuse_goal_info
+%-----------------------------------------------------------------------------%
+
+% :- func reuse_to_string(reuse_goal_info) = string. 
+
 %-----------------------------------------------------------------------------%
 % reuse_condition predicates 
 %-----------------------------------------------------------------------------%
@@ -173,6 +184,24 @@
 :- import_module pa_datastruct, pa_alias_as.
 :- import_module mercury_to_mercury, prog_out, prog_io, prog_io_util.
 :- import_module sr_util, pa_sr_util.
+
+%-----------------------------------------------------------------------------%
+/**
+reuse_to_string(Reuse) = String :- 
+	Reuse = empty, 
+	String = "empty".
+reuse_to_string(Reuse) = String :- 
+	Reuse = choice(_), 
+	String = "choice".
+reuse_to_string(Reuse) = String :- 
+	Reuse = potential_reuse(_), 
+	String = "potential_reuse".
+reuse_to_string(Reuse) = String :- 
+	Reuse = reuse, 
+	String = "reuse".
+**/
+%-----------------------------------------------------------------------------%
+
 
 reuse_condition_merge(C1, C2, C):-
 	(
Index: sr_indirect.m
===================================================================
RCS file: /home/mercury1/repository/mercury/compiler/Attic/sr_indirect.m,v
retrieving revision 1.1.2.24
diff -u -r1.1.2.24 sr_indirect.m
--- sr_indirect.m	2001/04/20 15:23:24	1.1.2.24
+++ sr_indirect.m	2001/06/22 14:23:23
@@ -514,7 +514,8 @@
 				Memo, LFUi, LBUi, 
 				Alias0, ConditionalReuse, Pool0, Pool),
 			goal_info_set_reuse(Info0,
-					reuse(reuse_call(ConditionalReuse)),
+					potential_reuse(
+						reuse_call(ConditionalReuse)),
 					Info),
 			YesNo = yes
 		;
@@ -526,7 +527,7 @@
 					Cause), 
 			
 			goal_info_set_reuse(Info0, 
-				reuse(missed_reuse_call(Cause)), Info), 
+				potential_reuse(missed_reuse_call(Cause)), Info), 
 			YesNo = no
 		)
 	).
Index: sr_split.m
===================================================================
RCS file: /home/mercury1/repository/mercury/compiler/Attic/sr_split.m,v
retrieving revision 1.1.2.14
diff -u -r1.1.2.14 sr_split.m
--- sr_split.m	2001/04/20 15:23:25	1.1.2.14
+++ sr_split.m	2001/06/22 14:23:24
@@ -17,12 +17,12 @@
 :- import_module hlds_module, io, string.
 :- import_module hlds_pred, sr_data, std_util, hlds_goal.
 
-	% create_multiple_versions(VirginHLDS, ReuseHLDS, FinalHLDS).
+	% create_multiple_versions(ReuseHLDS, FinalHLDS).
 	% Starting from the VirginHLDS, it computes a new HLDS where for
 	% each procedure having conditional reuse (ReuseHLDS), a new
 	% separate reuse-procedure is added. The calls can then also 
 	% be corrected so that they point to the correct reuse-versions.
-:- pred sr_split__create_multiple_versions(module_info::in, module_info::in,
+:- pred sr_split__create_multiple_versions(module_info::in,
 		module_info::out, io__state::di, io__state::uo) is det.
 
 :- pred create_reuse_pred(pred_proc_id::in, memo_reuse::in,
@@ -46,9 +46,9 @@
 reuse_predicate_name(PredName) :- 
 	string__prefix(PredName, "reuse__").
 
-sr_split__create_multiple_versions(VirginHLDS, ReuseHLDS, HLDS) --> 
+sr_split__create_multiple_versions(ReuseHLDS, HLDS) --> 
 		% compute the strongly connected components
-	{ create_versions(VirginHLDS, ReuseHLDS, HLDS1) },
+	{ create_versions(ReuseHLDS, HLDS1) },
 	{ reprocess_all_goals(HLDS1, HLDS) }.
 
 	% reprocess each of the procedures to make sure that all calls
@@ -104,28 +104,27 @@
 	).
 
 
-:- pred create_versions(module_info, module_info, module_info).
-:- mode create_versions(in, in, out) is det.
+:- pred create_versions(module_info, module_info).
+:- mode create_versions(in, out) is det.
 
-create_versions(VirginHLDS, ReuseHLDS, HLDS) :- 
+create_versions(ReuseHLDS, HLDS) :- 
 	module_info_predids(ReuseHLDS, PredIds), 
 	list__foldl(
-		create_versions_2(VirginHLDS),
+		create_versions_2,
 		PredIds,
 		ReuseHLDS, 
 		HLDS).
 
-:- pred create_versions_2(module_info::in, pred_id::in, 
+:- pred create_versions_2(pred_id::in, 
 			module_info::in, module_info::out) is det.
 
-create_versions_2(VirginHLDS, PredId , HLDS0, HLDS) :- 
+create_versions_2(PredId , HLDS0, HLDS) :- 
 	module_info_pred_info(HLDS0, PredId, PredInfo0), 
 	pred_info_procids(PredInfo0, ProcIds), 
 	list__foldl(
 		pred(Id::in, H0::in, H::out) is det :- 
 		(
-			create_versions_3(VirginHLDS, 
-				proc(PredId, Id), 
+			create_versions_3(proc(PredId, Id), 
 				H0, H)
 		),
 		ProcIds,
@@ -133,23 +132,24 @@
 		HLDS
 	).
 
-:- pred create_versions_3(module_info::in, pred_proc_id::in, 
+:- pred create_versions_3(pred_proc_id::in, 
 		module_info::in, module_info::out) is det.
 
-create_versions_3(VirginHLDS, PredProcId, WorkingHLDS, HLDS):- 
+create_versions_3(PredProcId, WorkingHLDS, HLDS):- 
 	module_info_pred_proc_info(WorkingHLDS, PredProcId, 
 				PredInfo0, ProcInfo0),
 	proc_info_reuse_information(ProcInfo0, Memo), 
-	module_info_pred_proc_info(VirginHLDS, PredProcId, _, 
-				CleanProcInfo), 
+% 	module_info_pred_proc_info(VirginHLDS, PredProcId, _, 
+%        			CleanProcInfo), 
 	proc_info_goal(ProcInfo0, ReuseGoal), 
 
 	(
 		Memo = no
 	-> 
 		% restore the old status of the procedure
-		module_info_set_pred_proc_info(WorkingHLDS, PredProcId,
-				PredInfo0, CleanProcInfo, HLDS)
+		% module_info_set_pred_proc_info(WorkingHLDS, PredProcId,
+	       	% 		PredInfo0, CleanProcInfo, HLDS)
+		HLDS = WorkingHLDS
 	;
 		(
 			memo_reuse_is_conditional(Memo) 
@@ -242,7 +242,8 @@
 	proc_info_set_reuse_information(ProcInfo, 
 				TabledReuse, ReuseProcInfo0),
 	(
-		MaybeReuseGoal = yes(ReuseGoal),
+		MaybeReuseGoal = yes(PotReuseGoal),
+		convert_potential_reuse_to_reuse(PotReuseGoal, ReuseGoal),
 		proc_info_set_goal(ReuseProcInfo0, ReuseGoal, ReuseProcInfo)
 	;
 		MaybeReuseGoal = no,
@@ -276,6 +277,83 @@
 			ReuseProcId, ReusePredInfo).
 
 %-----------------------------------------------------------------------------%
+
+:- pred convert_potential_reuse_to_reuse(hlds_goal::in, 
+						hlds_goal::out) is det.
+convert_potential_reuse_to_reuse(Goal0 - GoalInfo0, Goal - GoalInfo) :- 
+	Goal0 = conj(Goals0),
+	list__map(convert_potential_reuse_to_reuse, Goals0, Goals), 
+	Goal = conj(Goals), 
+	GoalInfo = GoalInfo0.
+convert_potential_reuse_to_reuse(Goal0 - GoalInfo0, Goal - GoalInfo) :- 
+	Goal0 = call(_,_,_,_,_,_),
+	Goal = Goal0, 
+	goal_info_get_reuse(GoalInfo0, Reuse0), 
+	convert_reuse(Reuse0, Reuse), 
+	goal_info_set_reuse(GoalInfo0, Reuse, GoalInfo).
+convert_potential_reuse_to_reuse(Goal0 - GoalInfo0, Goal - GoalInfo) :- 
+	Goal0 = generic_call(_,_,_,_),
+	Goal = Goal0, 
+	GoalInfo = GoalInfo0.
+convert_potential_reuse_to_reuse(Goal0 - GoalInfo0, Goal - GoalInfo) :- 
+	Goal0 = switch(X,Y,Cases0,Z),
+	list__map(
+		pred(C0::in, C::out) is det:-
+			( C0 = case(Id, G0), 
+			convert_potential_reuse_to_reuse(G0, G), 
+			C = case(Id, G)),
+		Cases0,
+		Cases),
+	Goal = switch(X, Y, Cases, Z),
+	GoalInfo = GoalInfo0.
+convert_potential_reuse_to_reuse(Goal0 - GoalInfo0, Goal - GoalInfo) :- 
+	Goal0 = unify(_,_,_,_,_),
+	Goal = Goal0, 
+	goal_info_get_reuse(GoalInfo0, Reuse0), 
+	convert_reuse(Reuse0,Reuse), 
+	goal_info_set_reuse(GoalInfo0, Reuse, GoalInfo).
+convert_potential_reuse_to_reuse(Goal0 - GoalInfo0, Goal - GoalInfo) :- 
+	Goal0 = disj(Goals0, SM),
+	list__map(convert_potential_reuse_to_reuse, Goals0, Goals), 
+	Goal = disj(Goals, SM), 
+	GoalInfo = GoalInfo0.
+convert_potential_reuse_to_reuse(Goal0 - GoalInfo0, Goal - GoalInfo) :- 
+	Goal0 = not(NegGoal0),
+	convert_potential_reuse_to_reuse(NegGoal0, NegGoal), 
+	Goal = not(NegGoal), 
+	GoalInfo = GoalInfo0. 
+convert_potential_reuse_to_reuse(Goal0 - GoalInfo0, Goal - GoalInfo) :- 
+	Goal0 = some(A, B, SG0), 
+	convert_potential_reuse_to_reuse(SG0, SG), 
+	Goal = some(A, B, SG),
+	GoalInfo = GoalInfo0. 
+convert_potential_reuse_to_reuse(Goal0 - GoalInfo0, Goal - GoalInfo) :- 
+	Goal0 = if_then_else(A, If0, Then0, Else0, B),
+	convert_potential_reuse_to_reuse(If0, If), 
+	convert_potential_reuse_to_reuse(Then0, Then), 
+	convert_potential_reuse_to_reuse(Else0, Else), 
+	Goal = if_then_else(A, If, Then, Else, B),
+	GoalInfo0 = GoalInfo. 
+convert_potential_reuse_to_reuse(Goal0 - GoalInfo0, Goal - GoalInfo) :- 
+	Goal0 = foreign_proc(_,_,_,_,_,_,_),
+	Goal = Goal0, 
+	GoalInfo = GoalInfo0.
+convert_potential_reuse_to_reuse(Goal0 - GoalInfo0, Goal - GoalInfo) :- 
+	Goal0 = par_conj(_,_),
+	Goal = Goal0, 
+	GoalInfo = GoalInfo0.
+convert_potential_reuse_to_reuse(Goal0 - GoalInfo0, Goal - GoalInfo) :- 
+	Goal0 = shorthand(_),
+	Goal = Goal0, 
+	GoalInfo = GoalInfo0.
+
+:- pred convert_reuse(reuse_goal_info::in, reuse_goal_info::out) is det.
+convert_reuse(R0, R):- R0 = empty, R = R0.
+convert_reuse(R0, _R):- R0 = choice(_),
+	error("(sr_split) convert_reuse: reuse_goal_info should not be choice/1 at this stage. ").
+convert_reuse(R0, R):- R0 = potential_reuse(S), R = reuse(S).
+convert_reuse(R0, R):- R0 = reuse(_), R = R0.
+
 %-----------------------------------------------------------------------------%
 :- pred process_goal(bool::in, hlds_goal::in, hlds_goal::out,
 		module_info::in, module_info::out) is det.
Index: structure_reuse.m
===================================================================
RCS file: /home/mercury1/repository/mercury/compiler/Attic/structure_reuse.m,v
retrieving revision 1.1.2.8
diff -u -r1.1.2.8 structure_reuse.m
--- structure_reuse.m	2001/02/07 10:19:12	1.1.2.8
+++ structure_reuse.m	2001/06/22 14:23:25
@@ -71,7 +71,7 @@
 		% Do the fixpoint computation to determine all the indirect
 		% reuse, and the implied conditions.
 	sr_indirect__compute_fixpoint(HLDS1, HLDS2),
-	sr_split__create_multiple_versions(HLDS0, HLDS2, HLDS), 
+	sr_split__create_multiple_versions(HLDS2, HLDS), 
 	sr_profile_run__structure_reuse_profiling(HLDS). 
 
 

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