[m-dev.] for review: more RTTI restructuring

[Fergus Henderson]

Here's a relative diff addressing Zoltan's review comments.
I'll go ahead and commit this now.

--- old/CHANGES6	Mon Apr 17 16:10:50 2000
+++ ./CHANGES6	Mon Apr 17 16:13:15 2000
@@ -25,10 +25,12 @@
 compiler/code_util.m:
 	Add new procedure `make_entry_label_from_rtti', for use by rtti_out.m.
 	Restructure the implementation of the predicates make_entry_label,
 	make_local_entry_label, and make_proc_label so that they work by first
 	calling rtti__make_proc_label.
+	Also update the documentation for code_util__compiler_generated,
+	adding an XXX comment saying that the name is misleading.
 
--- old/code_util.m	Mon Apr 17 14:58:02 2000
+++ code_util.m	Mon Apr 17 15:38:47 2000
@@ -97,6 +97,18 @@
 :- pred code_util__negate_the_test(list(instruction), list(instruction)).
 :- mode code_util__negate_the_test(in, out) is det.
 
+	% code_util__compiler_generated(PredInfo) succeeds iff
+	% the PredInfo is for a compiler generated instance of a
+	% type-specific special_pred (i.e. one of the __Unify__,
+	% __Index__, or __Compare__ predicates generated as a
+	% type-specific instance of unify/2, index/2, or compare/3).
+	% 
+	% XXX The name of this predicate is misleading, because there
+	% are other kinds of compiler-generated predicates, e.g. those
+	% for lambda expressions, those generated by higher-order
+	% specialization, ordinary type specialization, deforestation,
+	% etc., for which this predicate does not succeed.
+
 :- pred code_util__compiler_generated(pred_info).
 :- mode code_util__compiler_generated(in) is semidet.
 
@@ -256,9 +268,10 @@
 code_util__make_proc_label_from_rtti(RttiProcLabel, ProcLabel) :-
 	RttiProcLabel = rtti_proc_label(PredOrFunc, ThisModule,
 		PredModule, PredName, Arity, ArgTypes, _PredId, ProcId,
-		IsImported, _IsPseudoImported, _IsExported),
+		IsImported, _IsPseudoImported, _IsExported,
+		IsSpecialPredInstance),
 	(
-		special_pred_name_arity(_, _, PredName, Arity)
+		IsSpecialPredInstance = yes
 	->
 		(
 			special_pred_get_type(PredName, ArgTypes, Type),
@@ -377,9 +390,8 @@
 
 %-----------------------------------------------------------------------------%
 
-	% code_util__compiler_generated(PredInfo) should succeed iff
-	% the PredInfo is for a compiler generated predicate.
-
+	% XXX The name of this predicate is misleading -- see the comment
+	% in the declaration.
 code_util__compiler_generated(PredInfo) :-
 	pred_info_name(PredInfo, PredName),
 	pred_info_arity(PredInfo, PredArity),
--- old/ml_code_util.m	Mon Apr 17 14:58:03 2000
+++ ml_code_util.m	Mon Apr 17 15:39:58 2000
@@ -755,9 +755,9 @@
 ml_gen_pred_label_from_rtti(RttiProcLabel, MLDS_PredLabel, MLDS_Module) :-
 	RttiProcLabel = rtti_proc_label(PredOrFunc, ThisModule, PredModule,	
 		PredName, Arity, ArgTypes, _PredId, ProcId, IsImported,
-		_IsPseudoImported, _IsExported),
+		_IsPseudoImported, _IsExported, IsSpecialPredInstance),
 	(
-		special_pred_name_arity(_, _, PredName, Arity)
+		IsSpecialPredInstance = yes
 	->
 		(
 			special_pred_get_type(PredName, ArgTypes, Type),
--- old/rtti.m	Mon Apr 17 14:58:03 2000
+++ rtti.m	Mon Apr 17 16:07:05 2000
@@ -330,9 +330,27 @@
 			arg_types		::	list(type),
 			pred_id			::	pred_id,
 			proc_id			::	proc_id,
-			is_imported		::	bool,
-			is_pseudo_imported	::	bool,
-			is_exported		::	bool
+			%
+			% The following booleans hold values computed from the
+			% pred_info, using procedures
+			%	pred_info_is_imported/1,
+			%	pred_info_is_pseudo_imported/1,
+			%	pred_info_is_exported/1, and
+			%	pred_info_is_compiler_generated/1
+			% respectively.
+			% We store booleans here, rather than storing the
+			% pred_info, to avoid retaining a reference to the
+			% parts of the pred_info that we aren't interested in,
+			% so that those parts can be garbage collected.
+			% We use booleans rather than an import_status
+			% so that we can continue to use the above-mentioned
+			% abstract interfaces rather than hard-coding tests
+			% on the import_status.
+			%
+			is_imported			::	bool,
+			is_pseudo_imported		::	bool,
+			is_exported			::	bool,
+			is_special_pred_instance	::	bool
 		).
 
 	% Construct an rtti_proc_label for a given procedure.
@@ -358,7 +376,10 @@
 
 :- implementation.
 
-:- import_module llds_out, hlds_data, type_util.
+:- import_module code_util.	% for code_util__compiler_defined
+:- import_module llds_out.	% for name_mangle and sym_name_mangle
+:- import_module hlds_data, type_util.
+
 :- import_module string, require.
 
 rtti__make_proc_label(ModuleInfo, PredId, ProcId) = ProcLabel :-
@@ -372,9 +393,11 @@
 	IsImported = (pred_info_is_imported(PredInfo) -> yes ; no),
 	IsPseudoImp = (pred_info_is_pseudo_imported(PredInfo) -> yes ; no),
 	IsExported = (pred_info_is_exported(PredInfo) -> yes ; no),
+	IsSpecialPredInstance =
+		(code_util__compiler_generated(PredInfo) -> yes ; no),
 	ProcLabel = rtti_proc_label(PredOrFunc, ThisModule, PredModule,
-		    PredName, Arity, ArgTypes, PredId, ProcId,
-		    IsImported, IsPseudoImp, IsExported).
+		PredName, Arity, ArgTypes, PredId, ProcId,
+		IsImported, IsPseudoImp, IsExported, IsSpecialPredInstance).
 
 rtti__addr_to_string(RttiTypeId, RttiName, Str) :-
 	rtti__mangle_rtti_type_id(RttiTypeId, ModuleName, TypeName, A_str),

-- 
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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