[m-dev.] for review: GCC back-end: add Mmake support

[Fergus Henderson]

On 16-Jan-2001, Tyson Dowd <trd at cs.mu.OZ.AU> wrote:
> On 15-Jan-2001, Fergus Henderson <fjh at cs.mu.OZ.AU> wrote:
> > --- compiler/modules.m	2000/12/09 11:03:05	1.141
> > +++ compiler/modules.m	2001/01/15 01:27:43
> > @@ -1793,9 +1793,11 @@
> >  		),
> >  
> >  		globals__io_lookup_bool_option(highlevel_code, HighLevelCode),
> > -		( { HighLevelCode = yes } ->
> > +		globals__io_get_target(CompilationTarget),
> > +		( { HighLevelCode = yes, CompilationTarget = c } ->
> >  			%
> > -			% For --high-level-code, we need to make sure that we
> > +			% For --high-level-code with --target c,
> > +			% we need to make sure that we
> >  			% generate the header files for imported modules
> >  			% before compiling the C files, since the generated C
> >  			% files #include those header files.
> 
> This was beginning to bug me with the IL backend -- whenever a new .d
> file was generated it demanded a .h file.  Changing back and forth
> between asm_fast.gc and ilc meant that I kept needing to run mmake
> depend.  
> 
> Perhaps this (the fragment above) would be a suitable change for the
> release branch too?

Yes, good idea.  Done.  I've committed it on the release branch,
with the following log message:

	Estimated hours taken: 0.1

	compiler/modules.m:
		For targets other than C (i.e. IL), don't include the
		dependencies on .h files that we normally include for
		--high-level-code.

> .maybe_cs seems to be a misleading name in this case.
> 
> I can't think of a better one at the moment, so perhaps just document
> it?

Good point.  I'll fix the comments.  See diff below.

> > Index: scripts/mmake.in
> > ===================================================================
> > RCS file: /home/mercury1/repository/mercury/scripts/mmake.in,v
> > retrieving revision 1.30
> > diff -u -d -r1.30 mmake.in
> > --- scripts/mmake.in	1999/10/11 05:47:12	1.30
> > +++ scripts/mmake.in	2001/01/14 13:04:38
> > @@ -24,6 +24,11 @@
> >  		rather than in the current directory.
> >  		(If the current directory already contains a \`Mercury'
> >  		subdirectory, then this option is the default.)
> > +	--target asm:
> > +		Compile directly to assembler, rather than going via C.
> > +	--target c:
> > +		Compile via C, rather than going directly to assembler.
> > +		This is the default.
> >  	-s, --save-makefile:
> >  		Save the generated makefile to \`Mmake.makefile'.
> >  		This is useful for tracking down syntax errors in
> 
> --target il doesn't seem to be documented here, but you handle it
> below...

True.  It seemed logical to accept `--target il', for consistency with
the other programs (mmc, ml, etc.), but currently it doesn't actually
do anything useful (the code just treats `--target il' as equivalent
to `--target c'), so I didn't document it. 

I should have put some comments in the source explaining that
`--target asm' was deliberately undocumented and explaining why.
On further reflection, it's probably also a good idea to issue
a warning for `--target asm'.  Fixed, see diff below.

It would probably be nice to make `--target il' do something a bit
more useful, e.g. so that if you type `mmake foo.depend; mmake foo',
it builds foo.exe via IL.  But if so, it should be a separate change;
this change was adding Mmake support for the GCC back-end, not for IL ;-)

----------

Estimated hours taken: 0.25

compiler/modules.m:
	Add some comments about the use of $(*.maybe_cs) when
	compiling to assembler, to address trd's review comment.

Workspace: /home/hg/fjh/gcc-cvs/gcc/mercury
Index: compiler/modules.m
===================================================================
RCS file: /home/mercury1/repository/mercury/compiler/modules.m,v
retrieving revision 1.142
diff -u -d -r1.142 modules.m
--- compiler/modules.m	2001/01/17 02:43:11	1.142
+++ compiler/modules.m	2001/01/17 08:36:03
@@ -2869,9 +2869,10 @@
 	},
 
 	%
-	% We include $(foo.cs) first in the dependency list, before $(foo.os).
+	% When compiling to C, we want to include $(foo.cs) first in
+	% the dependency list, before $(foo.os).
 	% This is not strictly necessary, since the .$O files themselves depend
-	% on the .c files, but we do it to ensure that Make will try to
+	% on the .c files, but want to do it to ensure that Make will try to
 	% create all the C files first, thus detecting errors early,
 	% rather than first spending time compiling C files to .$O,
 	% which could be a waste of time if the program contains errors.
@@ -2882,6 +2883,13 @@
 	% This needs to be defined here in the .dep file rather than
 	% in the .dv file since it depends on the setting of the $(RM_C) file
 	% which can be overridden by the user's Mmakefile.
+	%
+	% When compiling to assembler, we want to do the same kind of
+	% thing, for the same reason, but with the `.s' files rather
+	% than the `.c' files.  So if TARGET_ASM=yes, we define
+	% $(foo.maybe_cs) to be $(foo.ss).
+	% XXX The name `.maybe_cs' is a bit misleading in this case.
+	%     Perhaps we should change it.
 	%
 	module_name_to_file_name(SourceModuleName, "", no, ExeFileName),
 	io__write_strings(DepStream, [

----------

Estimated hours taken: 0.25

scripts/mmake.in:
	Add some comments explaining that the `--target il' option is
	not supported.  Issue a warning if it is used.

Workspace: /home/hg/fjh/gcc-cvs/gcc/mercury
Index: scripts/mmake.in
===================================================================
RCS file: /home/mercury1/repository/mercury/scripts/mmake.in,v
retrieving revision 1.31
diff -u -d -r1.31 mmake.in
--- scripts/mmake.in	2001/01/17 02:45:07	1.31
+++ scripts/mmake.in	2001/01/17 09:12:19
@@ -28,7 +28,12 @@
 		Compile directly to assembler, rather than going via C.
 	--target c:
 		Compile via C, rather than going directly to assembler.
-		This is the default.
+		This is the default."
+	# XXX `--target il' is not documented because it is not yet
+	#     supported.
+	#--target il:
+	#	Compile via IL, rather than going via C or assembler.
+Help="$Help\
 	-s, --save-makefile:
 		Save the generated makefile to \`Mmake.makefile'.
 		This is useful for tracking down syntax errors in
@@ -103,7 +108,12 @@
 		--target)
 			case "$2" in
 				asm)	target_asm=yes ;;
-				c|il)	target_asm=no ;;
+				c)	target_asm=no ;;
+				il)	# XXX we should do something
+					# sensible for `--target il'
+					echo "$0: warning: \`--target il'"
+						"option not supported." 1>&2
+					target_asm=no ;;
 				*)	echo "$0: invalid argument to" \
 						"\`--target' option" 1>&2
 					exit 1 ;;
-- 
Fergus Henderson <fjh at cs.mu.oz.au>  |  "I have always known that the pursuit
                                    |  of excellence is a lethal habit"
WWW: <http://www.cs.mu.oz.au/~fjh>  |     -- the last words of T. S. Garp.
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