[m-rev.] diff: fix typeclass inlining bug

[Simon Taylor]

Estimated hours taken: 3
Branches: main

compiler/inlining.m:
	Fix a bug in inlining of procedures with typeclass constraints.
	The type_info location for the callee overwrote the location
	in the caller, but the location in the callee may have been
	computed by extracting type_infos from typeclass_infos in the
	caller, so it wouldn't be valid when computing the locations of
	the type variables in the head of the caller.

	Remove a partial work-around for this bug, which disabled
	inlining of procedures with class constraints when tracing
	is enabled. The work-around didn't prevent the code generator
	abort occurring when constructing closure layouts.

tests/valid/Mmakefile:
tests/valid/typeclass_inlining_bug.m:
	Test case.

Index: compiler/inlining.m
===================================================================
RCS file: /home/mercury1/repository/mercury/compiler/inlining.m,v
retrieving revision 1.107
diff -u -u -r1.107 inlining.m
--- compiler/inlining.m	28 Mar 2002 03:43:05 -0000	1.107
+++ compiler/inlining.m	19 Jul 2002 14:07:53 -0000
@@ -727,7 +727,13 @@
 
 	apply_substitutions_to_var_map(CalleeTypeInfoVarMap0, 
 		TypeRenaming, TypeSubn, Subn, CalleeTypeInfoVarMap1),
-	map__merge(TypeInfoVarMap0, CalleeTypeInfoVarMap1,
+
+	% Prefer the type_info_locn from the caller.
+	% The type_infos or typeclass_infos passed to the callee may
+	% have been produced by extracting type_infos or typeclass_infos
+	% from typeclass_infos in the caller, so they won't necessarily
+	% be the same.
+	map__overlay(CalleeTypeInfoVarMap1, TypeInfoVarMap0,
 		TypeInfoVarMap).
 
 inlining__get_type_substitution(HeadTypes, ArgTypes,
@@ -835,10 +841,10 @@
 	is semidet.
 
 inlining__should_inline_proc(PredId, ProcId, BuiltinState, HighLevelCode,
-		Tracing, InlinedProcs, CallingPredMarkers, ModuleInfo) :-
+		_Tracing, InlinedProcs, CallingPredMarkers, ModuleInfo) :-
 	InlinePromisedPure = yes,
 	inlining__can_inline_proc(PredId, ProcId, BuiltinState,
-		HighLevelCode, Tracing, InlinePromisedPure,
+		HighLevelCode, InlinePromisedPure,
 		CallingPredMarkers, ModuleInfo),
 
 	% OK, we could inline it - but should we?  Apply our heuristic.
@@ -854,18 +860,16 @@
 		CallingPredMarkers, ModuleInfo) :-
 	module_info_globals(ModuleInfo, Globals),
 	globals__lookup_bool_option(Globals, highlevel_code, HighLevelCode), 
-	globals__get_trace_level(Globals, TraceLevel),
-	Tracing = bool__not(trace_level_is_none(TraceLevel)),
 	inlining__can_inline_proc(PredId, ProcId, BuiltinState,
-		HighLevelCode, Tracing, InlinePromisedPure,
+		HighLevelCode, InlinePromisedPure,
 		CallingPredMarkers, ModuleInfo).
 
 :- pred inlining__can_inline_proc(pred_id, proc_id, builtin_state, bool,
-	bool, bool, pred_markers, module_info).
-:- mode inlining__can_inline_proc(in, in, in, in, in, in, in, in) is semidet.
+	bool, pred_markers, module_info).
+:- mode inlining__can_inline_proc(in, in, in, in, in, in, in) is semidet.
 
 inlining__can_inline_proc(PredId, ProcId, BuiltinState, HighLevelCode,
-		Tracing, InlinePromisedPure, CallingPredMarkers, ModuleInfo) :-
+		InlinePromisedPure, CallingPredMarkers, ModuleInfo) :-
 
 	% don't inline builtins, the code generator will handle them
 	BuiltinState = not_builtin,
@@ -904,22 +908,6 @@
 		CalledGoal = foreign_proc(_,_,_,_,_,_,_) - _,
 		proc_info_interface_determinism(ProcInfo, Detism),
 		( Detism = nondet ; Detism = multidet )
-	),
-
-	% XXX:
-	% If tracing is enabled, then the code generator will need to figure
-	% out the locations of typeinfos inside typeclass_infos. At the moment,
-	% due to a bug, the algorithm for doing this figuring can cause a
-	% compiler abort if we inline calls that have typeclass constraints.
-	(
-		Tracing = yes
-	=>
-		(
-			pred_info_clauses_info(PredInfo, ClausesInfo),
-			TypeClassInfoVarMap = ClausesInfo ^
-				clause_typeclass_info_varmap,
-			map__is_empty(TypeClassInfoVarMap)
-		)
 	),
 
 	% Only inline foreign_code if it is appropriate for
Index: tests/valid/Mmakefile
===================================================================
RCS file: /home/mercury1/repository/tests/valid/Mmakefile,v
retrieving revision 1.107
diff -u -u -r1.107 Mmakefile
--- tests/valid/Mmakefile	14 Jul 2002 15:12:41 -0000	1.107
+++ tests/valid/Mmakefile	19 Jul 2002 06:09:12 -0000
@@ -166,6 +166,7 @@
 	tricky_ite.m \
 	two_pragma_c_codes.m \
 	two_way_unif.m \
+	typeclass_inlining_bug.m \
 	type_inf_ambig_test.m \
 	unbound_inst_var.m \
 	unbound_tvar_in_lambda.m \
Index: tests/valid/typeclass_inlining_bug.m
===================================================================
RCS file: tests/valid/typeclass_inlining_bug.m
diff -N tests/valid/typeclass_inlining_bug.m
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ tests/valid/typeclass_inlining_bug.m	19 Jul 2002 06:09:33 -0000
@@ -0,0 +1,40 @@
+:- module typeclass_inlining_bug.
+
+:- interface.
+
+:- import_module list.
+
+:- type analysis
+	--->	some [Call, Answer] analysis(Call, Answer)
+			=> analysis(Call, Answer).
+
+:- typeclass analysis(Call, Answer) <=
+		(call_pattern(Call), answer_pattern(Answer))
+			where
+[].
+
+:- type analysis_name == string.
+
+:- typeclass call_pattern(Call) where [].
+
+:- typeclass answer_pattern(Answer) where [].
+
+:- type analysis_info.
+
+:- pred lookup_call_pattern(Call::in, list(analysis)::in,
+	list(Answer)::out) is det <= analysis(Call, Answer).
+
+:- implementation.
+
+:- import_module map, require, set, std_util.
+
+lookup_call_pattern(CallPattern, Results, AnswerPatterns) :-
+	AnswerPatterns = list__filter_map(filter_results(CallPattern),
+			Results).
+
+:- func filter_results(Call, analysis) = Answer is semidet
+		<= (call_pattern(Call), answer_pattern(Answer)).
+
+filter_results(_, analysis(_, Answer0)) = Answer :-
+	univ(Answer0) = univ(Answer).
+
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