From b063b0a874bbc4724894885b0a633865675db9ff Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Dagfinn=20Ilmari=20Manns=C3=A5ker?= <ilmari@ilmari.org>
Date: Fri, 31 Mar 2017 15:04:15 +0100
Subject: [PATCH] Define and use symbolic constants for LvFLAGS

---
 doop.c |  4 ++--
 mg.c   | 10 +++++-----
 pp.c   | 10 +++++-----
 sv.h   |  4 ++++
 4 files changed, 16 insertions(+), 12 deletions(-)

diff --git a/doop.c b/doop.c
index 0dd4bdf6031b..0a546cce8f94 100644
--- a/doop.c
+++ b/doop.c
@@ -927,8 +927,8 @@ Perl_do_vecset(pTHX_ SV *sv)
     /* some out-of-range errors have been deferred if/until the LV is
      * actually written to: f(vec($s,-1,8)) is not always fatal */
     if (errflags) {
-        assert(!(errflags & ~(1|4)));
-        if (errflags & 1)
+        assert(!(errflags & ~(LVf_NEG_OFF|LVf_OUT_OF_RANGE)));
+        if (errflags & LVf_NEG_OFF)
             Perl_croak_nocontext("Negative offset to vec in lvalue context");
         Perl_croak_nocontext("Out of memory!");
     }
diff --git a/mg.c b/mg.c
index 969d183d6a5a..99c7aa2c1434 100644
--- a/mg.c
+++ b/mg.c
@@ -2197,8 +2197,8 @@ Perl_magic_getsubstr(pTHX_ SV *sv, MAGIC *mg)
     const char * const tmps = SvPV_const(lsv,len);
     STRLEN offs = LvTARGOFF(sv);
     STRLEN rem = LvTARGLEN(sv);
-    const bool negoff = LvFLAGS(sv) & 1;
-    const bool negrem = LvFLAGS(sv) & 2;
+    const bool negoff = LvFLAGS(sv) & LVf_NEG_OFF;
+    const bool negrem = LvFLAGS(sv) & LVf_NEG_LEN;
 
     PERL_ARGS_ASSERT_MAGIC_GETSUBSTR;
     PERL_UNUSED_ARG(mg);
@@ -2229,8 +2229,8 @@ Perl_magic_setsubstr(pTHX_ SV *sv, MAGIC *mg)
     SV * const lsv = LvTARG(sv);
     STRLEN lvoff = LvTARGOFF(sv);
     STRLEN lvlen = LvTARGLEN(sv);
-    const bool negoff = LvFLAGS(sv) & 1;
-    const bool neglen = LvFLAGS(sv) & 2;
+    const bool negoff = LvFLAGS(sv) & LVf_NEG_OFF;
+    const bool neglen = LvFLAGS(sv) & LVf_NEG_LEN;
 
     PERL_ARGS_ASSERT_MAGIC_SETSUBSTR;
     PERL_UNUSED_ARG(mg);
@@ -2311,7 +2311,7 @@ Perl_magic_getvec(pTHX_ SV *sv, MAGIC *mg)
     PERL_UNUSED_ARG(mg);
 
     /* non-zero errflags implies deferred out-of-range condition */
-    assert(!(errflags & ~(1|4)));
+    assert(!(errflags & ~(LVf_NEG_OFF|LVf_OUT_OF_RANGE)));
     sv_setuv(sv, errflags ? 0 : do_vecget(lsv, LvTARGOFF(sv), LvTARGLEN(sv)));
 
     return 0;
diff --git a/pp.c b/pp.c
index 0c31062c3aed..6df21011affd 100644
--- a/pp.c
+++ b/pp.c
@@ -3377,11 +3377,11 @@ PP(pp_substr)
 	LvTARGOFF(ret) =
 	    pos1_is_uv || pos1_iv >= 0
 		? (STRLEN)(UV)pos1_iv
-		: (LvFLAGS(ret) |= 1, (STRLEN)(UV)-pos1_iv);
+		: (LvFLAGS(ret) |= LVf_NEG_OFF, (STRLEN)(UV)-pos1_iv);
 	LvTARGLEN(ret) =
 	    len_is_uv || len_iv > 0
 		? (STRLEN)(UV)len_iv
-		: (LvFLAGS(ret) |= 2, (STRLEN)(UV)-len_iv);
+		: (LvFLAGS(ret) |= LVf_NEG_LEN, (STRLEN)(UV)-len_iv);
 
 	PUSHs(ret);    /* avoid SvSETMAGIC here */
 	RETURN;
@@ -3488,12 +3488,12 @@ PP(pp_vec)
 
         /* avoid a large UV being wrapped to a negative value */
         if (SvIOK_UV(offsetsv) && SvUVX(offsetsv) > (UV)IV_MAX)
-            errflags = 4; /* out of range */
+            errflags = LVf_OUT_OF_RANGE;
         else if (iv < 0)
-            errflags = (1|4); /* negative offset, out of range */
+            errflags = (LVf_NEG_OFF|LVf_OUT_OF_RANGE);
 #if PTRSIZE < IVSIZE
         else if (iv > Size_t_MAX)
-            errflags = 4; /* out of range */
+            errflags = LVf_OUT_OF_RANGE;
 #endif
         else
             offset = (STRLEN)iv;
diff --git a/sv.h b/sv.h
index 51e9b0ba6649..71c494b3675d 100644
--- a/sv.h
+++ b/sv.h
@@ -1402,6 +1402,10 @@ object type. Exposed to perl code via Internals::SvREADONLY().
 #define LvTARGLEN(sv)	((XPVLV*)  SvANY(sv))->xlv_targlen
 #define LvFLAGS(sv)	((XPVLV*)  SvANY(sv))->xlv_flags
 
+#define LVf_NEG_OFF      0x1
+#define LVf_NEG_LEN      0x2
+#define LVf_OUT_OF_RANGE 0x4
+
 #define IoIFP(sv)	(sv)->sv_u.svu_fp
 #define IoOFP(sv)	((XPVIO*)  SvANY(sv))->xio_ofp
 #define IoDIRP(sv)	((XPVIO*)  SvANY(sv))->xio_dirp