A naive pass at this is:

oolong:~/research/parrot coke$ cvs diff imcc/symreg.c
Index: imcc/symreg.c
=========================================================
==========
RCS file: /cvs/public/parrot/imcc/symreg.c,v
retrieving revision 1.55
diff -b -u -r1.55 symreg.c
--- imcc/symreg.c       17 Jul 2004 08:07:27 -0000      1.55
+++ imcc/symreg.c       30 Oct 2004 04:45:21 -0000
@@ -287,6 +287,11 @@
         ident->next = namespace->idents;
         namespace->idents = ident;
     }
+    if (_get_sym(cur_unit->hash,fullname)) {
+        fataly(1, sourcefile, line,
+            "duplicate .local or .sym: '%s'",
+                     fullname);
+    }
     r = mk_symreg(fullname, t);
     r->type = VTIDENTIFIER;
     free(name);

This causes a few tests to fail:

t/library/dumper.t      13  3328    13   13 100.00%  1-13
t/library/parrotlib.t    1   256     6    1  16.67%  3
t/library/streams.t     12  3072    21   12  57.14%  2 4-5 8 10-12 14-17 20
t/pmc/iter.t             1   256    44    1   2.27%  11

/Some/ of these seem to be valid errors. But it also seems to not like having .subs with the
same name as a .local inside that sub.

Also, the errors message isn't reporting properly.

Help?

That is to say, the file and line number appear to be off.

Will Coleda via RT wrote:

Will Coleda via RT <parrotbug-follo...@parrotcode.org> wrote:

While this patch isn't really wrong it's probably a bit dangerous and
might break too much existing code.

Anyway I'd prefer a more general approach:

* split PASM and PIR lexer and parser into two distinct sets
  (the -p prefix option for bison is helpful here, see ast/ast.[ly])

* generate exact location information, again see above files

* Cleanup and straighten the grammar files

* fix names handling: global constants, locals per unit, subroutine
  names per namespace

* get rid of support for stack calling conventions (.param and friends)
  in PIR mode

* get rid of related cruft in imcc/cfg.c

* get rid of the still existing globals, move all into appropriate
  structures, mostly IMC_Unit.

* and a lot more todo, e.g. create a compiler API

Imcc has too much historical ballast. Since it was a standalone language
that produced PASM files it has gone through numerous changes and hacks.
Now it's since quite a time Parrot's compiler and integrated.

These changes shouldn't really interfer with current ongoing hacks in
reg_alloc.c as long as that file isn't touched and the SymReg structure
keeps the relevant information for register allocation.

leo