[m-rev.] diff: improve intermodule structure sharing analysis

[Julien Fischer]

With this diff the compiler can perform structure sharing analysis for most of
the standard library.  It currently dies with a map lookup failure when
building the .trans_opt file for the varset module (specifically with
the predicate varset.vars/2) - I haven't looked into that yet.

Estimated hours taken: 1
Branches: main

Improve the integration of the structure sharing analysis into the
(transitive-)intermodule optimization framework.

compiler/structure_sharing.analysis.m:
	When building the the optimization interfaces we were performing
	structure sharing analysis but the results were not being written out
	to the .opt files.  Add code to do this.

	Don't write out structure sharing pragmas for procedures created by
	type specialization - the compiler can't read them back in because the
	type specialized versions don't yet exist when it reads the
	.{opt,trans_opt} files.  (This is a long standing limitation.)

compiler/handle_options.m:
	Avoid unexpected behaviour: `--structure-sharing' should not imply
	`--trans-intermod-opt'.

Julien.

Index: compiler/handle_options.m
===================================================================
RCS file: /home/mercury1/repository/mercury/compiler/handle_options.m,v
retrieving revision 1.258
diff -u -r1.258 handle_options.m
--- compiler/handle_options.m	24 Feb 2006 07:11:09 -0000	1.258
+++ compiler/handle_options.m	28 Feb 2006 07:09:33 -0000
@@ -727,8 +727,6 @@
         option_implies(check_termination2, termination2, bool(yes), !Globals),
         option_implies(check_termination2, warn_missing_trans_opt_files,
             bool(yes), !Globals),
-        option_implies(structure_sharing_analysis,
-            transitive_optimization, bool(yes), !Globals),
         option_implies(make_transitive_opt_interface, transitive_optimization,
             bool(yes), !Globals),
         option_implies(transitive_optimization, intermodule_optimization,
Index: compiler/structure_sharing.analysis.m
===================================================================
RCS file: /home/mercury1/repository/mercury/compiler/structure_sharing.analysis.m,v
retrieving revision 1.5
diff -u -r1.5 structure_sharing.analysis.m
--- compiler/structure_sharing.analysis.m	27 Feb 2006 08:05:21 -0000	1.5
+++ compiler/structure_sharing.analysis.m	28 Feb 2006 07:48:06 -0000
@@ -6,8 +6,8 @@
 % Public License - see the file COPYING in the Mercury distribution.
 %-----------------------------------------------------------------------------%

-% File: structure_sharing.analysis.m
-% Main authors: nancy
+% File: structure_sharing.analysis.m.
+% Main authors: nancy.

 % Implementation of the structure sharing analysis needed for compile-time
 % garbage collection (CTGC).
@@ -46,7 +46,9 @@
 :- import_module libs.options.
 :- import_module ll_backend.liveness.
 :- import_module mdbcomp.prim_data.
+:- import_module parse_tree.error_util.
 :- import_module parse_tree.mercury_to_mercury.
+:- import_module parse_tree.modules.
 :- import_module parse_tree.prog_data.
 :- import_module parse_tree.prog_out.
 :- import_module transform_hlds.ctgc.fixpoint_table.
@@ -58,21 +60,37 @@
 :- import_module io.
 :- import_module list.
 :- import_module map.
+:- import_module set.
 :- import_module std_util.
 :- import_module string.
 :- import_module term.

 %-----------------------------------------------------------------------------%

-structure_sharing_analysis(!ModuleInfo, SharingTable, !IO):-
-    % preliminary step:
-    % annotate the liveness (as in liveness.m)
+structure_sharing_analysis(!ModuleInfo, !:SharingTable, !IO):-
+    %
+    % Annotate the HLDS with liveness information.
+    %
     annotate_liveness(!ModuleInfo, !IO),
-    % load all structure sharing information present in the HLDS.
-    load_structure_sharing_table(!.ModuleInfo, SharingTable0),
-
-    % analysis
-    sharing_analysis(!ModuleInfo, SharingTable0, SharingTable, !IO).
+    %
+    % Load all structure sharing information present in the HLDS.
+    %
+    load_structure_sharing_table(!.ModuleInfo, !:SharingTable),
+    %
+    % Analyse structure sharing for the module.
+    %
+    sharing_analysis(!ModuleInfo, !SharingTable, !IO),
+    %
+    % Maybe write structure sharing pragmas to .opt files.
+    %
+    globals.io_lookup_bool_option(make_optimization_interface,
+        MakeOptInt, !IO),
+    (
+        MakeOptInt = yes,
+        make_opt_int(!.ModuleInfo, !IO)
+    ;
+        MakeOptInt = no
+    ).

 %-----------------------------------------------------------------------------%
 %
@@ -126,7 +144,10 @@
     sharing_as_table::in, sharing_as_table::out, io::di, io::uo) is det.

 sharing_analysis(!ModuleInfo, !SharingTable, !IO):-
-    % Perform the analysis based on the strongly connected components.
+    %
+    % Perform a bottom-up traversal of the SCCs in the program,
+    % analysing structure sharing in each one as we go.
+    %
     module_info_ensure_dependency_info(!ModuleInfo),
     module_info_get_maybe_dependency_info(!.ModuleInfo, MaybeDepInfo),
     (
@@ -613,20 +634,62 @@
     fixpoint_table.get_final_semidet(PPId, T).

 %-----------------------------------------------------------------------------%
+%
+% Code for writing out optimization interfaces
+%
+
+:- pred make_opt_int(module_info::in, io::di, io::uo) is det.
+
+make_opt_int(ModuleInfo, !IO) :-
+    module_info_get_name(ModuleInfo, ModuleName),
+    module_name_to_file_name(ModuleName, ".opt.tmp", no, OptFileName, !IO),
+    globals.io_lookup_bool_option(verbose, Verbose, !IO),
+    maybe_write_string(Verbose, "% Appending structure_sharing pragmas to ",
+        !IO),
+    maybe_write_string(Verbose, add_quotes(OptFileName), !IO),
+    maybe_write_string(Verbose, "...", !IO),
+    maybe_flush_output(Verbose, !IO),
+    io.open_append(OptFileName, OptFileRes, !IO),
+    (
+        OptFileRes = ok(OptFile),
+        io.set_output_stream(OptFile, OldStream, !IO),
+        module_info_predids(ModuleInfo, PredIds),
+        list.foldl(write_pred_sharing_info(ModuleInfo), PredIds, !IO),
+        io.set_output_stream(OldStream, _, !IO),
+        io.close_output(OptFile, !IO),
+        maybe_write_string(Verbose, " done.\n", !IO)
+    ;
+        OptFileRes = error(IOError),
+        maybe_write_string(Verbose, " failed!\n", !IO),
+        io.error_message(IOError, IOErrorMessage),
+        io.write_strings(["Error opening file `",
+            OptFileName, "' for output: ", IOErrorMessage], !IO),
+        io.set_exit_status(1, !IO)
+    ).
+
+%-----------------------------------------------------------------------------%
+%
+% Code for writing out structure_sharing pragmas
+%

 write_pred_sharing_info(ModuleInfo, PredId, !IO) :-
     module_info_pred_info(ModuleInfo, PredId, PredInfo),
     pred_info_import_status(PredInfo, ImportStatus),
+    module_info_get_type_spec_info(ModuleInfo, TypeSpecInfo),
+    TypeSpecInfo = type_spec_info(_, TypeSpecForcePreds, _, _),
     (
         (
             ImportStatus = exported
         ;
             ImportStatus = opt_exported
         ),
-        \+ is_unify_or_compare_pred(PredInfo)
+        \+ is_unify_or_compare_pred(PredInfo),
+
+        % XXX These should be allowed, but the predicate declaration for the
+        % specialized predicate is not produced before the termination pragmas
+        % are read in, resulting in an undefined predicate error.
+        \+ set.member(PredId, TypeSpecForcePreds)
     ->
-        % XXX We most probably need to handle predicate produced by type
-        % specialization here as well (see termination.m).
         PredName = pred_info_name(PredInfo),
         ProcIds = pred_info_procids(PredInfo),
         PredOrFunc = pred_info_is_pred_or_func(PredInfo),
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