From: Nicholas Clark <nick@ccl4.org>
Date: Fri, 6 Apr 2007 21:53:46 +0000 (+0000)
Subject: Only append ?? match ops to the list used by reset. This saves memory
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=ad639bfb68f3fce4864d833950ed2ff9dd1cb28d;p=p5sagit%2Fp5-mst-13.2.git

Only append ?? match ops to the list used by reset. This saves memory
and time.

p4raw-id: //depot/perl@30857
---

diff --git a/op.c b/op.c
index e0be444..56b9d9f 100644
--- a/op.c
+++ b/op.c
@@ -3326,20 +3326,6 @@ Perl_newPMOP(pTHX_ I32 type, I32 flags)
     }
 #endif
 
-    /* append to pm list */
-    if (type != OP_TRANS && PL_curstash) {
-	MAGIC *mg = mg_find((SV*)PL_curstash, PERL_MAGIC_symtab);
-	U32 elements;
-	if (!mg) {
-	    mg = sv_magicext((SV*)PL_curstash, 0, PERL_MAGIC_symtab, 0, 0, 0);
-	}
-	elements = mg->mg_len / sizeof(PMOP**);
-	Renewc(mg->mg_ptr, elements + 1, PMOP*, char);
-	((PMOP**)mg->mg_ptr) [elements++] = pmop;
-	mg->mg_len = elements * sizeof(PMOP**);
-	PmopSTASH_set(pmop,PL_curstash);
-    }
-
     return CHECKOP(type, pmop);
 }
 
diff --git a/op.h b/op.h
index 0dee522..f99cd3b 100644
--- a/op.h
+++ b/op.h
@@ -326,6 +326,11 @@ struct pmop {
     REGEXP *    op_pmregexp;            /* compiled expression */
 #endif
     U32		op_pmflags;
+    /* This field is only needed so that PMOPs can delete themselves from the
+       list held by the stash. In turn, that list is only needed for reset
+       to work correctly, and is now only a list of ops used by ?? matches,
+       which are rare. Hence it would be useful if we could find a way to
+       shave it. */
 #ifdef USE_ITHREADS
     char *	op_pmstashpv;
 #else
diff --git a/toke.c b/toke.c
index 5a79dcd..0485df1 100644
--- a/toke.c
+++ b/toke.c
@@ -10841,8 +10841,28 @@ S_scan_pat(pTHX_ char *start, I32 type)
     }
 
     pm = (PMOP*)newPMOP(type, 0);
-    if (PL_multi_open == '?')
+    if (PL_multi_open == '?') {
+	/* This is the only point in the code that sets PMf_ONCE:  */
 	pm->op_pmflags |= PMf_ONCE;
+
+	/* Hence it's safe to do this bit of PMOP book-keeping here, which
+	   allows us to restrict the list needed by reset to just the ??
+	   matches.  */
+	assert(type != OP_TRANS);
+	if (PL_curstash) {
+	    MAGIC *mg = mg_find((SV*)PL_curstash, PERL_MAGIC_symtab);
+	    U32 elements;
+	    if (!mg) {
+		mg = sv_magicext((SV*)PL_curstash, 0, PERL_MAGIC_symtab, 0, 0,
+				 0);
+	    }
+	    elements = mg->mg_len / sizeof(PMOP**);
+	    Renewc(mg->mg_ptr, elements + 1, PMOP*, char);
+	    ((PMOP**)mg->mg_ptr) [elements++] = pm;
+	    mg->mg_len = elements * sizeof(PMOP**);
+	    PmopSTASH_set(pm,PL_curstash);
+	}
+    }
 #ifdef PERL_MAD
     modstart = s;
 #endif