diff: bug fix

[Simon TAYLOR]

Hi Fergus,

Could you please review this.

Simon.


Estimated hours taken: 1.5

Fix a determinism analysis abort ("inappropriate determinism inside a 
negation") which was caused by det_analysis.m not updating the instmap 
to include the initial insts of the lambda variables before processing 
a lambda goal. This problem was also present in cse_detection.m and 
simplify.m.

compiler/cse_detection.m
compiler/det_analysis.m
compiler/simplify.m
	Make sure that the instmap is updated before processing a lambda goal.

compiler/switch_detection.m
compiler/instmap.m
	Move some code to update the instmap before a lambda goal from
	switch_detection.m into a new predicate instmap__pre_lambda_update/5,
	which takes an instmap and a list of modes of a lambda expression,
	and adds the initial insts of the lambda variables to the instmap.

tests/valid/Mmake
tests/valid/lambda_instmap_bug.m
	Regression test.	



Index: cse_detection.m
===================================================================
RCS file: /home/staff/zs/imp/mercury/compiler/cse_detection.m,v
retrieving revision 1.42
diff -u -r1.42 cse_detection.m
--- cse_detection.m	1997/05/05 11:16:44	1.42
+++ cse_detection.m	1997/05/06 07:36:31
@@ -209,9 +209,12 @@
 detect_cse_in_goal_2(call(A,B,C,D,E,F), _, _, CseInfo, CseInfo, no,
 	call(A,B,C,D,E,F)).
 
-detect_cse_in_goal_2(unify(A,B0,C,D,E), _, InstMap, CseInfo0, CseInfo, Redo,
+detect_cse_in_goal_2(unify(A,B0,C,D,E), _, InstMap0, CseInfo0, CseInfo, Redo,
 		unify(A,B,C,D,E)) :-
 	( B0 = lambda_goal(PredOrFunc, Vars, Modes, Det, Goal0) ->
+		CseInfo0 = cse_info(_, _, ModuleInfo),
+		instmap__pre_lambda_update(ModuleInfo, 
+			Vars, Modes, InstMap0, InstMap),
 		detect_cse_in_goal(Goal0, InstMap, CseInfo0, CseInfo, Redo,
 			Goal),
 		B = lambda_goal(PredOrFunc, Vars, Modes, Det, Goal)
Index: det_analysis.m
===================================================================
RCS file: /home/staff/zs/imp/mercury/compiler/det_analysis.m,v
retrieving revision 1.114
diff -u -r1.114 det_analysis.m
--- det_analysis.m	1997/05/05 11:16:49	1.114
+++ det_analysis.m	1997/05/06 07:36:46
@@ -448,7 +448,10 @@
 		;	
 			LambdaSolnContext = all_solns
 		),
-		det_infer_goal(Goal0, InstMap0, LambdaSolnContext, DetInfo,
+		det_info_get_module_info(DetInfo, ModuleInfo),
+		instmap__pre_lambda_update(ModuleInfo, Vars, Modes,
+			InstMap0, InstMap1),
+		det_infer_goal(Goal0, InstMap1, LambdaSolnContext, DetInfo,
 				Goal, LambdaInferredDet, Msgs1),
 		det_check_lambda(LambdaDeclaredDet, LambdaInferredDet,
 				Goal, GoalInfo, DetInfo, Msgs2),
Index: instmap.m
===================================================================
RCS file: /home/staff/zs/imp/mercury/compiler/instmap.m,v
retrieving revision 1.6
diff -u -r1.6 instmap.m
--- instmap.m	1997/02/17 01:26:38	1.6
+++ instmap.m	1997/05/06 07:37:40
@@ -146,6 +146,12 @@
 		instmap, instmap, module_info, module_info).
 :- mode instmap__bind_var_to_functor(in, in, in, out, in, out) is det.
 
+	% Update the given instmap to include the initial insts of the
+	% lambda variables.
+:- pred instmap__pre_lambda_update(module_info, list(var), list(mode),
+		instmap, instmap).
+:- mode instmap__pre_lambda_update(in, in, in, in, out) is det.
+
 %-----------------------------------------------------------------------------%
 
 	% Given two instmaps and a set of variables, compute an instmap delta
@@ -422,6 +428,11 @@
 
 %-----------------------------------------------------------------------------%
 
+instmap__pre_lambda_update(ModuleInfo, Vars, Modes, InstMap0, InstMap) :-
+	mode_list_get_initial_insts(Modes, ModuleInfo, Insts),
+	assoc_list__from_corresponding_lists(Vars, Insts, VarInsts),
+	instmap_delta_from_assoc_list(VarInsts, InstMapDelta),
+	instmap__apply_instmap_delta(InstMap0, InstMapDelta, InstMap).
 
 %-----------------------------------------------------------------------------%
 
Index: simplify.m
===================================================================
RCS file: /home/staff/zs/imp/mercury/compiler/simplify.m,v
retrieving revision 1.31
diff -u -r1.31 simplify.m
--- simplify.m	1997/05/05 11:17:30	1.31
+++ simplify.m	1997/05/06 07:37:00
@@ -440,8 +440,14 @@
 			LambdaGoal0)
 	->
 		simplify_info_get_common_info(Info0, Common),
-		simplify__goal(LambdaGoal0, LambdaGoal, Info0, Info1),
-		simplify_info_set_common_info(Info1, Common, Info),
+		simplify_info_get_module_info(Info0, ModuleInfo),
+		simplify_info_get_instmap(Info0, InstMap0),
+		instmap__pre_lambda_update(ModuleInfo, Vars, Modes,
+			InstMap0, InstMap1),
+		simplify_info_set_instmap(Info0, InstMap1, Info1),
+		simplify__goal(LambdaGoal0, LambdaGoal, Info1, Info2),
+		simplify_info_set_common_info(Info2, Common, Info3),
+		simplify_info_set_instmap(Info3, InstMap0, Info),
 		RT = lambda_goal(PredOrFunc, Vars, Modes, LambdaDeclaredDet,
 			LambdaGoal),
 		Goal = unify(LT0, RT, M, U0, C),
Index: switch_detection.m
===================================================================
RCS file: /home/staff/zs/imp/mercury/compiler/switch_detection.m,v
retrieving revision 1.68
diff -u -r1.68 switch_detection.m
--- switch_detection.m	1997/05/05 11:17:34	1.68
+++ switch_detection.m	1997/05/06 07:37:16
@@ -168,10 +168,8 @@
 	( RHS0 = lambda_goal(PredOrFunc, Vars, Modes, Det, Goal0) ->
 		% we need to insert the initial insts for the lambda
 		% variables in the instmap before processing the lambda goal
-		mode_list_get_initial_insts(Modes, ModuleInfo, Insts),
-		assoc_list__from_corresponding_lists(Vars, Insts, VarInsts),
-		instmap_delta_from_assoc_list(VarInsts, InstmapDelta),
-		instmap__apply_instmap_delta(InstMap0, InstmapDelta, InstMap1),
+		instmap__pre_lambda_update(ModuleInfo, 
+			Vars, Modes, InstMap0, InstMap1),
 		detect_switches_in_goal(Goal0, InstMap1, VarTypes, ModuleInfo,
 			Goal),
 		RHS = lambda_goal(PredOrFunc, Vars, Modes, Det, Goal)



% Regression test for a case where cse_detection.m, det_analysis.m 
% and simplify.m were not updating the instmap before processing
% a lambda expression, causing an abort in determinism analysis.
:- module lambda_instmap_bug.

:- interface.

:- import_module set, std_util.

:- type instr == pair(instruction, string).

:- type instruction
	--->	clear(int)
	;	drop(int)
	;	join(int, int, int).

:- pred detect_streams(set(int), list(instr), list(instr)).
:- mode detect_streams(in, in, out) is det.

:- implementation.

:- import_module list.

detect_streams(Streams, Instrs0, Instrs) :-

	% Don't attempt to clear or drop streams.
	IsNotStreamClear = 
		lambda([Instr::in] is semidet, (
			\+ (
				( Instr = clear(Rel) - _
				; Instr = drop(Rel) - _
				),
				set__member(Rel, Streams)
			)
		)),
	list__filter(IsNotStreamClear, Instrs0, Instrs).