[m-dev.] For review: Simplify specification of some per-program flags

[Warwick Harvey]

Fergus wrote:
> On 01-Jul-1999, Warwick Harvey <wharvey at cs.monash.edu.au> wrote:
> > Anyway, with the GRADEFLAGS stuff, if one does the substitution for both the 
> > `$@' and `$*' variables, one gets the grade flags repeated in the call to 
> > `c2init', since both match.  This is probably harmless.  However, I'm going 
> > to argue that whenever `$(patsubst %_init.c,%,$@)' gives you `foo', 
> > `$(patsubst %_init,%,$*)' will also give you `foo' (`_init.c' files are only 
> > ever built by implicit rules, right?), so the substitution is only necessary 
> > for the latter.
> 
> No, `_init.c' files are almost always generated by explicit rules.

Of course.  Clearly I'm still not thinking straight.  :-(  I think I need a 
head transplant.

`$*' _is_ defined for these rules anyway (which is why it worked when I 
tested it), as described in the GNU Make documentation:

     In an explicit rule, there is no stem; so `$*' cannot be determined
     in that way.  Instead, if the target name ends with a recognized
     suffix (*note Old-Fashioned Suffix Rules: Suffix Rules.), `$*' is
     set to the target name minus the suffix.  For example, if the
     target name is `foo.c', then `$*' is set to `foo', since `.c' is a
     suffix.  GNU `make' does this bizarre thing only for compatibility
     with other implementations of `make'.  You should generally avoid
     using `$*' except in implicit rules or static pattern rules.

Clearly this usage is deprecated, so I think everybody's in agreement that I 
should go with the harmless repetition.

Given my track record lately, I think I'll post one more diff before I 
commit (to be sure, to be sure):

Estimated hours taken: 3.5

Specifying GRADEFLAGS and C2INITFLAGS on a per-program basis didn't work
properly for `_init.*' files.  Rather than just specifying `-foo' versions,
one had to specify `-foo_init.c' or `-foo_init' versions instead or as well.
This change corrects this.

scripts/Mmake.vars.in:
	Strip any `_init' suffix from the `$*' automatic variable and any
	`_init.c' suffix from the `$@' automatic variable used in the
	per-target definitions of GRADEFLAGS and C2INITFLAGS.

Index: Mmake.vars.in
===================================================================
RCS file: /home/mercury1/repository/mercury/scripts/Mmake.vars.in,v
retrieving revision 1.24
diff -u -r1.24 Mmake.vars.in
--- Mmake.vars.in	1998/12/06 23:48:56	1.24
+++ Mmake.vars.in	1999/07/01 10:24:08
@@ -184,11 +184,13 @@
 # undefined variables is enabled.
 
 TARGET_GRADEFLAGS = \
-  $(maybe-base-GRADEFLAGS-$(findstring undefined,$(origin GRADEFLAGS-$*))) \
-  $(maybe-target-GRADEFLAGS-$(findstring undefined,$(origin GRADEFLAGS-$@)))
-maybe-base-GRADEFLAGS- = $(GRADEFLAGS-$*)
+  $(maybe-base-GRADEFLAGS-$(findstring undefined,\
+		$(origin GRADEFLAGS-$(patsubst %_init,%,$*)))) \
+  $(maybe-target-GRADEFLAGS-$(findstring undefined,\
+  		$(origin GRADEFLAGS-$(patsubst %_init.c,%,$@))))
+maybe-base-GRADEFLAGS- = $(GRADEFLAGS-$(patsubst %_init,%,$*))
 maybe-base-GRADEFLAGS-undefined =
-maybe-target-GRADEFLAGS- = $(GRADEFLAGS-$@)
+maybe-target-GRADEFLAGS- = $(GRADEFLAGS-$(patsubst %_init.c,%,$@))
 maybe-target-GRADEFLAGS-undefined =
 
 TARGET_MCFLAGS = \
@@ -197,8 +199,9 @@
 maybe-base-MCFLAGS-undefined =
 
 TARGET_C2INITFLAGS = \
-  $(maybe-target-C2INITFLAGS-$(findstring undefined,$(origin 
C2INITFLAGS-$@)))
-maybe-target-C2INITFLAGS- = $(C2INITFLAGS-$@)
+  $(maybe-target-C2INITFLAGS-$(findstring undefined,\
+		$(origin C2INITFLAGS-$(patsubst %_init.c,%,$@))))
+maybe-target-C2INITFLAGS- = $(C2INITFLAGS-$(patsubst %_init.c,%,$@))
 maybe-target-C2INITFLAGS-undefined =
 
 TARGET_MGNUCFLAGS = \


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