[perl #119799] Set breakpoints without *DB::dbline

The elements of the %{"_<..."} hashes (where ‘...’ is the filename),
whose keys are line numbers, are used to set breakpoints on the given
lines.  The corresponding @{"_<..."} array contains the actual lines
of source code.

%{"_<..."} actually acts on the array of lines that @DB::dbline is
aliased to.  The assumption is that *DB::dbline = *{"_<..."} will have
taken place first.  Hence, all %{"_<..."} hashes are the same, when it
comes to writing to keys.

It is more useful for each %{"_<..."} hash to set breakpoints on its
corresponding file’s lines regardless of whether @DB::dbline has been
aliased, so that is what this commit does.

Each hash’s mg_obj pointer in its dbfile magic now points to the
array, and magic_setdbline uses it instead of PL_DBline.

1 files changed, 2 insertions, 1 deletions

diff --git a/mg.c b/mg.c
index f88428a925..83aafa4016 100644
--- a/mg.c
+++ b/mg.c
@@ -1974,7 +1974,8 @@ Perl_magic_setdbline(pTHX_ SV *sv, MAGIC *mg)
 
     /* Use sv_2iv instead of SvIV() as the former generates smaller code, and
        setting/clearing debugger breakpoints is not a hot path.  */
-    svp = av_fetch(GvAV(PL_DBline), sv_2iv(MUTABLE_SV((mg)->mg_ptr)), FALSE);
+    svp = av_fetch(MUTABLE_AV(mg->mg_obj),
+		   sv_2iv(MUTABLE_SV((mg)->mg_ptr)), FALSE);
 
     if (svp && SvIOKp(*svp)) {
 	OP * const o = INT2PTR(OP*,SvIVX(*svp));