[m-rev.] diff: workaround to fix nightly builds

[Mark Brown]

On 15-Aug-2005, Julien Fischer <juliensf at cs.mu.OZ.AU> wrote:
> 
> Estimated hours taken: 0.1
> Branches: main
> 
> library/Mercury.options:
> 	Workaround a bug in the compiler that is causing the
> 	library to fail to build in grade asm_fast.gc.tr.debug
> 	at -O5.  This is just to get the nightly builds up and
> 	running again.
> 

The following diff appears to fix the problem.  I'll commit it after
further testing, assuming it passes.

Cheers,
Mark.

Estimated hours taken: 1
Branches: main

Fix a problem exposed by the exists_cast transformation.  saved_vars.m was
renaming prog_vars in procedure bodies without updating the rtti_varmaps.
As a result, pre-birth sets were being calculated wrongly in some cases,
leading to a failure of the code generator when compiliing
library/version_store.m at -O5 in debug grades.

compiler/saved_vars.m:
	Build up a variable renaming in the slot_info.  Apply it to the
	rtti_varmaps at the end of processing.

library/Mercury.options:
	Remove the workaround for this bug.

library/map.m:
	Add a new type, renaming/1, which is a map whose key and value types
	are the same.  Move two predicates for manipulating renamings from
	simplify.m into map.m.

compiler/simplify.m:
	Use the map library instead of local definitions.

Index: compiler/saved_vars.m
===================================================================
RCS file: /home/mercury1/repository/mercury/compiler/saved_vars.m,v
retrieving revision 1.49
diff -u -r1.49 saved_vars.m
--- compiler/saved_vars.m	31 May 2005 06:55:31 -0000	1.49
+++ compiler/saved_vars.m	15 Aug 2005 13:00:35 -0000
@@ -71,16 +71,22 @@
 	proc_info_goal(!.ProcInfo, Goal0),
 	proc_info_varset(!.ProcInfo, Varset0),
 	proc_info_vartypes(!.ProcInfo, VarTypes0),
+	proc_info_rtti_varmaps(!.ProcInfo, RttiVarMaps0),
 	init_slot_info(Varset0, VarTypes0, SlotInfo0),
 
 	saved_vars_in_goal(Goal0, Goal1, SlotInfo0, SlotInfo),
 
-	final_slot_info(Varset1, VarTypes1, SlotInfo),
-	proc_info_headvars(!.ProcInfo, HeadVars),
+	final_slot_info(Varset1, VarTypes1, RecRenaming, SlotInfo),
 
 	% hlds_out__write_goal(Goal1, !.ModuleInfo, Varset1, 0, "\n"),
 
+	% Apply the prog_var substitution to the rtti_varmaps.
+	map__transitive_closure(RecRenaming, Renaming),
+	apply_substitutions_to_rtti_varmaps(map__init, map__init, Renaming,
+		RttiVarMaps0, RttiVarMaps),
+
 	% recompute the nonlocals for each goal
+	proc_info_headvars(!.ProcInfo, HeadVars),
 	implicitly_quantify_clause_body(HeadVars, _Warnings, Goal1, Goal2,
 		Varset1, Varset, VarTypes1, VarTypes),
 	proc_info_get_initial_instmap(!.ProcInfo, !.ModuleInfo, InstMap0),
@@ -92,7 +98,8 @@
 
 	proc_info_set_goal(Goal, !ProcInfo),
 	proc_info_set_varset(Varset, !ProcInfo),
-	proc_info_set_vartypes(VarTypes, !ProcInfo).
+	proc_info_set_vartypes(VarTypes, !ProcInfo),
+	proc_info_set_rtti_varmaps(RttiVarMaps, !ProcInfo).
 
 %-----------------------------------------------------------------------------%
 
@@ -503,28 +510,32 @@
 :- type slot_info
 	---> slot_info(
 		prog_varset,
-		vartypes
+		vartypes,
+		renaming(prog_var)
 	).
 
 :- pred init_slot_info(prog_varset::in, map(prog_var, type)::in,
 	slot_info::out) is det.
 
-init_slot_info(Varset, VarTypes, slot_info(Varset, VarTypes)).
+init_slot_info(Varset, VarTypes, slot_info(Varset, VarTypes, map__init)).
 
-:- pred final_slot_info(prog_varset::out, vartypes::out, slot_info::in) is det.
+:- pred final_slot_info(prog_varset::out, vartypes::out,
+	renaming(prog_var)::out, slot_info::in) is det.
 
-final_slot_info(Varset, VarTypes, slot_info(Varset, VarTypes)).
+final_slot_info(Varset, VarTypes, Renaming, SlotInfo) :-
+	SlotInfo = slot_info(Varset, VarTypes, Renaming).
 
-:- pred rename_var(prog_var::in, prog_var::out, map(prog_var, prog_var)::out,
+:- pred rename_var(prog_var::in, prog_var::out, renaming(prog_var)::out,
 	slot_info::in, slot_info::out) is det.
 
 rename_var(Var, NewVar, Substitution, !SlotInfo) :-
-	!.SlotInfo = slot_info(Varset0, VarTypes0),
+	!.SlotInfo = slot_info(Varset0, VarTypes0, Renaming0),
 	varset__new_var(Varset0, NewVar, Varset),
 	map__from_assoc_list([Var - NewVar], Substitution),
 	map__lookup(VarTypes0, Var, Type),
 	map__det_insert(VarTypes0, NewVar, Type, VarTypes),
-	!:SlotInfo = slot_info(Varset, VarTypes).
+	map__det_insert(Renaming0, Var, NewVar, Renaming),
+	!:SlotInfo = slot_info(Varset, VarTypes, Renaming).
 
 %-----------------------------------------------------------------------------%
 
Index: compiler/simplify.m
===================================================================
RCS file: /home/mercury1/repository/mercury/compiler/simplify.m,v
retrieving revision 1.146
diff -u -r1.146 simplify.m
--- compiler/simplify.m	15 Aug 2005 07:18:30 -0000	1.146
+++ compiler/simplify.m	15 Aug 2005 12:55:45 -0000
@@ -1798,7 +1798,7 @@
         ( map__is_empty(Subn1) ->
             Goals = Goals0
         ;
-            renaming_transitive_closure(Subn1, Subn),
+            map__transitive_closure(Subn1, Subn),
             list__reverse(RevGoals, Goals1),
             MustSub = no,
             goal_util__rename_vars_in_goals(Goals1, MustSub, Subn, Goals),
@@ -1814,7 +1814,7 @@
         Goals = Goals0
     ).
 
-:- type var_renaming == map(prog_var, prog_var).
+:- type var_renaming == renaming(prog_var).
 
 :- pred simplify__find_excess_assigns_in_conj(trace_level::in, bool::in,
     prog_varset::in, set(prog_var)::in, list(hlds_goal)::in,
@@ -1845,8 +1845,8 @@
     Unif = assign(LeftVar0, RightVar0),
 
     % Check if we've already substituted one or both of the variables.
-    find_renamed_var(!.Subn, LeftVar0, LeftVar),
-    find_renamed_var(!.Subn, RightVar0, RightVar),
+    map__search_transitively(!.Subn, LeftVar0, LeftVar),
+    map__search_transitively(!.Subn, RightVar0, RightVar),
 
     CanElimLeft = ( set__member(LeftVar, ConjNonLocals) -> no ; yes ),
     CanElimRight = ( set__member(RightVar, ConjNonLocals) -> no ; yes ),
@@ -1890,26 +1890,6 @@
         string__to_int(Suffix, _)
     ).
 
-:- pred find_renamed_var(var_renaming::in, prog_var::in, prog_var::out) is det.
-
-find_renamed_var(Subn, Var0, Var) :-
-    ( map__search(Subn, Var0, Var1) ->
-        find_renamed_var(Subn, Var1, Var)
-    ;
-        Var = Var0
-    ).
-
-    % Collapse chains of renamings.
-    %
-:- pred renaming_transitive_closure(var_renaming::in, var_renaming::out)
-    is det.
-
-renaming_transitive_closure(VarRenaming0, VarRenaming) :-
-    map__map_values(
-        (pred(_::in, Value0::in, Value::out) is det :-
-            find_renamed_var(VarRenaming0, Value0, Value)
-        ), VarRenaming0, VarRenaming).
-
 %-----------------------------------------------------------------------------%
 
 :- pred simplify__switch(prog_var::in, list(case)::in, list(case)::in,
Index: library/Mercury.options
===================================================================
RCS file: /home/mercury1/repository/mercury/library/Mercury.options,v
retrieving revision 1.9
diff -u -r1.9 Mercury.options
--- library/Mercury.options	15 Aug 2005 07:28:25 -0000	1.9
+++ library/Mercury.options	15 Aug 2005 12:57:34 -0000
@@ -20,7 +20,6 @@
 MCFLAGS-std_util += --no-halt-at-warn
 MCFLAGS-dir += --no-halt-at-warn
 MCFLAGS-exception += --no-halt-at-warn
-MCFLAGS-version_store += -O0
 
 # io.m uses library features that are supported by POSIX but which are not
 # part of ANSI C, such as `struct stat', fileno(), and putenv().
Index: library/map.m
===================================================================
RCS file: /home/mercury1/repository/mercury/library/map.m,v
retrieving revision 1.98
diff -u -r1.98 map.m
--- library/map.m	16 Jun 2005 04:08:02 -0000	1.98
+++ library/map.m	15 Aug 2005 09:13:39 -0000
@@ -442,6 +442,24 @@
 :- func 'map__det_elem :='(K, map(K, V), V) = map(K, V).
 
 %-----------------------------------------------------------------------------%
+
+	% A "renaming" is a map where the keys and values have the
+	% same type.
+	%
+:- type renaming(T) == map(T, T).
+
+	% Follow a chain of renamed elements until we find one that is
+	% not renamed.
+	%
+:- func map__search_transitively(renaming(T), T) = T.
+:- pred map__search_transitively(renaming(T)::in, T::in, T::out) is det.
+
+	% Collapse a recursive renaming into a non-recursive one.
+	%
+:- func map__transitive_closure(renaming(T)) = renaming(T).
+:- pred map__transitive_closure(renaming(T)::in, renaming(T)::out) is det.
+
+%-----------------------------------------------------------------------------%
 %-----------------------------------------------------------------------------%
 
 :- implementation.
@@ -1105,3 +1123,25 @@
 'map__elem :='(Key, Map, Value) = map__set(Map, Key, Value).
 
 'map__det_elem :='(Key, Map, Value) = map__det_update(Map, Key, Value).
+
+%-----------------------------------------------------------------------------%
+
+map__search_transitively(Renaming, !Val) :-
+	( map__search(Renaming, !Val) ->
+		map__search_transitively(Renaming, !Val)
+	;
+		true
+	).
+
+map__search_transitively(Renaming, Val0) = Val :-
+	map__search_transitively(Renaming, Val0, Val).
+
+map__transitive_closure(!Renaming) :-
+	Pred = (pred(_::in, !.Val::in, !:Val::out) is det :-
+			map__search_transitively(!.Renaming, !Val)
+		),
+	map__map_values(Pred, !Renaming).
+
+map__transitive_closure(Renaming0) = Renaming :-
+	map__transitive_closure(Renaming0, Renaming).
+
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