allow wrap-around of PL_cop_seqmax

After a large number of evals, PL_cop_seqmax (a U32) will wrap around
again to zero. Make the code handle this case by:

1) When incrementing PL_cop_seqmax, never allow its value to become
   equal to PERL_PADSEQ_INTRO;
2) When testing for COP_SEQ_RANGE_LOW < seq <= COP_SEQ_RANGE_HIGH,
   allow for the fact that _HIGH may be lower than _LOW.

This is a final fix for  [perl #83364].

diff --git a/op.c b/op.c
index ad94f6e..2e15a8d 100644 (file)
--- a/op.c
+++ b/op.c
@@ -4356,6 +4356,8 @@ Perl_utilize(pTHX_ int aver, I32 floor, OP *version, OP *idop, OP *arg)
     PL_parser->copline = NOLINE;
     PL_parser->expect = XSTATE;
     PL_cop_seqmax++; /* Purely for B::*'s benefit */
+    if (PL_cop_seqmax == PERL_PADSEQ_INTRO) /* not a legal value */
+       PL_cop_seqmax++;
 
 #ifdef PERL_MAD
     if (!PL_madskills) {

diff --git a/pad.c b/pad.c
index 439d85f..3d5f827 100644 (file)
--- a/pad.c
+++ b/pad.c
@@ -863,11 +863,35 @@ S_pad_findlex(pTHX_ const char *name, const CV* cv, U32 seq, int warn,
            if (namesv && namesv != &PL_sv_undef
                    && strEQ(SvPVX_const(namesv), name))
            {
-               if (SvFAKE(namesv))
+               if (SvFAKE(namesv)) {
                    fake_offset = offset; /* in case we don't find a real one */
-               else if (  seq >  COP_SEQ_RANGE_LOW(namesv)     /* min */
-                       && seq <= COP_SEQ_RANGE_HIGH(namesv))   /* max */
-                   break;
+                   continue;
+               }
+               /* is seq within the range _LOW to _HIGH ?
+                * This is complicated by the fact that PL_cop_seqmax
+                * may have wrapped around at some point */
+               if (COP_SEQ_RANGE_LOW(namesv) == PERL_PADSEQ_INTRO)
+                   continue; /* not yet introduced */
+
+               if (COP_SEQ_RANGE_HIGH(namesv) == PERL_PADSEQ_INTRO) {
+                   /* in compiling scope */
+                   if (
+                       (seq >  COP_SEQ_RANGE_LOW(namesv))
+                       ? (seq - COP_SEQ_RANGE_LOW(namesv) < (U32_MAX >> 1))
+                       : (COP_SEQ_RANGE_LOW(namesv) - seq > (U32_MAX >> 1))
+                   )
+                      break;
+               }
+               else if (
+                   (COP_SEQ_RANGE_LOW(namesv) > COP_SEQ_RANGE_HIGH(namesv))
+                   ?
+                       (  seq >  COP_SEQ_RANGE_LOW(namesv)
+                       || seq <= COP_SEQ_RANGE_HIGH(namesv))
+
+                   :    (  seq >  COP_SEQ_RANGE_LOW(namesv)
+                        && seq <= COP_SEQ_RANGE_HIGH(namesv))
+               )
+               break;
            }
        }
 
@@ -1161,6 +1185,7 @@ Perl_intro_my(pTHX)
     dVAR;
     SV **svp;
     I32 i;
+    U32 seq;
 
     ASSERT_CURPAD_ACTIVE("intro_my");
     if (! PL_min_intro_pending)
@@ -1183,12 +1208,16 @@ Perl_intro_my(pTHX)
            );
        }
     }
+    seq = PL_cop_seqmax;
+    PL_cop_seqmax++;
+    if (PL_cop_seqmax == PERL_PADSEQ_INTRO) /* not a legal value */
+       PL_cop_seqmax++;
     PL_min_intro_pending = 0;
     PL_comppad_name_fill = PL_max_intro_pending; /* Needn't search higher */
     DEBUG_Xv(PerlIO_printf(Perl_debug_log,
-               "Pad intromy: seq -> %ld\n", (long)(PL_cop_seqmax+1)));
+               "Pad intromy: seq -> %ld\n", (long)(PL_cop_seqmax)));
 
-    return PL_cop_seqmax++;
+    return seq;
 }
 
 /*
@@ -1235,6 +1264,8 @@ Perl_pad_leavemy(pTHX)
        }
     }
     PL_cop_seqmax++;
+    if (PL_cop_seqmax == PERL_PADSEQ_INTRO) /* not a legal value */
+       PL_cop_seqmax++;
     DEBUG_Xv(PerlIO_printf(Perl_debug_log,
            "Pad leavemy: seq = %ld\n", (long)PL_cop_seqmax));
 }