Trying my "remove the pTHXes" patch again

Message-ID: <20060209154018.GA14610@petdance.com>

p4raw-id: //depot/perl@27136

19 files changed, 210 insertions, 194 deletions

diff --git a/Makefile.SH b/Makefile.SH
index 940708bf0f..00034908ce 100644
--- a/Makefile.SH
+++ b/Makefile.SH
@@ -359,30 +359,33 @@ obj3 = doop$(OBJ_EXT) doio$(OBJ_EXT) regexec$(OBJ_EXT) utf8$(OBJ_EXT) taint$(OBJ
 obj = $(obj1) $(obj2) $(obj3) $(ARCHOBJS)
 
 lintflags = \
-    -bhn \
+    -b \
+    -n \
     -p \
-    -s \
     -Ncheck=%all \
     -Nlevel=4 \
     -errfmt=src \
     -errtags \
+    -erroff=E_ASSIGN_NARROW_CONV \
     -erroff=E_BAD_PTR_CAST \
+    -erroff=E_BAD_PTR_CAST_ALIGN \
+    -erroff=E_BAD_PTR_INT_COMBINATION \
+    -erroff=E_BAD_SIGN_EXTEND \
     -erroff=E_BLOCK_DECL_UNUSED \
+    -erroff=E_CASE_FALLTHRU \
     -erroff=E_CONSTANT_CONDITION \
-    -erroff=E_BAD_PTR_CAST_ALIGN \
-    -erroff=E_PTRDIFF_OVERFLOW \
+    -erroff=E_EQUALITY_NOT_ASSIGNMENT \
     -erroff=E_EXPR_NULL_EFFECT \
-    -erroff=E_BAD_PTR_INT_COMBINATION \
-    -erroff=E_LOOP_EMPTY \
-    -erroff=E_TRUE_LOGICAL_EXPR \
     -erroff=E_FALSE_LOGICAL_EXPR \
-    -erroff=E_INDISTING_FROM_TRUNC \
-    -erroff=E_POINTER_TO_OBJECT \
-    -erroff=E_ASSIGN_NARROW_CONV \
-    -erroff=E_BAD_SIGN_EXTEND \
     -erroff=E_INCL_NUSD \
+    -erroff=E_INDISTING_FROM_TRUNC \
+    -erroff=E_LOOP_EMPTY \
     -erroff=E_MAIN_PARAM \
-    -Wfoo.flow
+    -erroff=E_POINTER_TO_OBJECT \
+    -erroff=E_PTRDIFF_OVERFLOW \
+    -erroff=E_SHIFT_CNT_NEG_TOO_BIG_L \
+    -erroff=E_STATIC_UNUSED \
+    -erroff=E_TRUE_LOGICAL_EXPR \
 
 .c$(OBJ_EXT):
 	$(CCCMD) $(PLDLFLAGS) $*.c
diff --git a/cc_runtime.h b/cc_runtime.h
index 3815d3a5e3..cb8c4caeee 100644
--- a/cc_runtime.h
+++ b/cc_runtime.h
@@ -54,8 +54,7 @@
 	switch (ret) {				\
 	case 0:					\
 	    PL_op = ppaddr(aTHX);		\
-	    /* XXX PL_retstack[PL_retstack_ix - 1] = Nullop;	*/ \
-	    if (PL_op != nxt) CALLRUNOPS();		\
+	    if (PL_op != nxt) CALLRUNOPS();	\
 	    JMPENV_POP;				\
 	    break;				\
 	case 1: JMPENV_POP; JMPENV_JUMP(1);	\
diff --git a/cop.h b/cop.h
index 6c26e0ee5a..f0429b17a9 100644
--- a/cop.h
+++ b/cop.h
@@ -150,8 +150,6 @@ struct cop {
     SV *	cop_io;		/* lexical IO defaults */
 };
 
-#define Nullcop Null(COP*)
-
 #ifdef USE_ITHREADS
 #  define CopFILE(c)		((c)->cop_file)
 #  define CopFILEGV(c)		(CopFILE(c) \
@@ -254,7 +252,7 @@ struct block_sub {
 	cx->blk_sub.cv = cv;						\
 	cx->blk_sub.olddepth = CvDEPTH(cv);				\
 	cx->blk_sub.hasargs = hasargs;					\
-	cx->blk_sub.retop = Nullop;						\
+	cx->blk_sub.retop = NULL;					\
 	if (!CvDEPTH(cv)) {						\
 	    (void)SvREFCNT_inc(cv);					\
 	    (void)SvREFCNT_inc(cv);					\
@@ -276,7 +274,7 @@ struct block_sub {
 #define PUSHFORMAT(cx)							\
 	cx->blk_sub.cv = cv;						\
 	cx->blk_sub.gv = gv;						\
-	cx->blk_sub.retop = Nullop;					\
+	cx->blk_sub.retop = NULL;					\
 	cx->blk_sub.hasargs = 0;					\
 	cx->blk_sub.dfoutgv = PL_defoutgv;				\
 	(void)SvREFCNT_inc(cx->blk_sub.dfoutgv)
@@ -348,7 +346,7 @@ struct block_eval {
 	cx->blk_eval.old_eval_root = PL_eval_root;			\
 	cx->blk_eval.cur_text = PL_linestr;				\
 	cx->blk_eval.cv = NULL; /* set by doeval(), as applicable */	\
-	cx->blk_eval.retop = Nullop; 					\
+	cx->blk_eval.retop = NULL;					\
 	cx->blk_eval.cur_top_env = PL_top_env; 				\
     } STMT_END
 
diff --git a/deb.c b/deb.c
index a21066e697..df2ccffaa4 100644
--- a/deb.c
+++ b/deb.c
@@ -32,6 +32,8 @@ Perl_deb_nocontext(const char *pat, ...)
     va_start(args, pat);
     vdeb(pat, &args);
     va_end(args);
+#else
+    PERL_UNUSED_ARG(pat);
 #endif /* DEBUGGING */
 }
 #endif
@@ -54,7 +56,7 @@ Perl_vdeb(pTHX_ const char *pat, va_list *args)
 {
 #ifdef DEBUGGING
     dVAR;
-    char* file = OutCopFILE(PL_curcop);
+    const char* const file = OutCopFILE(PL_curcop);
 
     PerlIO_printf(Perl_debug_log, "(%s:%ld)\t", (file ? file : "<free>"),
 		  (long)CopLINE(PL_curcop));
diff --git a/embed.fnc b/embed.fnc
index a1c3d2217b..90294ba388 100644
--- a/embed.fnc
+++ b/embed.fnc
@@ -1042,12 +1042,12 @@ paRxo	|void*	|get_arena	|int svtype
 s	|void	|hsplit		|NN HV *hv
 s	|void	|hfreeentries	|NN HV *hv
 sa	|HE*	|new_he
-sa	|HEK*	|save_hek_flags	|NN const char *str|I32 len|U32 hash|int flags
-s	|void	|hv_magic_check	|NN HV *hv|NN bool *needs_copy|NN bool *needs_store
+sanR	|HEK*	|save_hek_flags	|NN const char *str|I32 len|U32 hash|int flags
+sn	|void	|hv_magic_check	|NN HV *hv|NN bool *needs_copy|NN bool *needs_store
 s	|void	|unshare_hek_or_pvn|NULLOK const HEK* hek|NULLOK const char* str|I32 len|U32 hash
 sR	|HEK*	|share_hek_flags|NN const char* sv|I32 len|U32 hash|int flags
 rs	|void	|hv_notallowed	|int flags|NN const char *key|I32 klen|NN const char *msg
-s	|struct xpvhv_aux*|hv_auxinit|NN HV *hv
+sRn	|struct xpvhv_aux*|hv_auxinit|NN HV *hv
 sM	|SV*	|hv_delete_common|NULLOK HV* tb|NULLOK SV* keysv|NULLOK const char* key \
 		|STRLEN klen|int k_flags|I32 d_flags|U32 hash
 sM	|HE*	|hv_fetch_common|NULLOK HV* tb|NULLOK SV* keysv|NULLOK const char* key \
@@ -1107,7 +1107,7 @@ pR	|OP*	|ck_substr	|NN OP *o
 pR	|OP*	|ck_svconst	|NN OP *o
 pR	|OP*	|ck_trunc	|NN OP *o
 pR	|OP*	|ck_unpack	|NN OP *o
-sR	|bool	|is_handle_constructor|NN const OP *o|I32 numargs
+sRn	|bool	|is_handle_constructor|NN const OP *o|I32 numargs
 sR	|I32	|is_list_assignment|NULLOK const OP *o
 s	|void	|cop_free	|NN COP *cop
 s	|OP*	|modkids	|NULLOK OP *o|I32 type
@@ -1116,7 +1116,7 @@ sR	|OP*	|newDEFSVOP
 sR	|OP*	|new_logop	|I32 type|I32 flags|NN OP **firstp|NN OP **otherp
 s	|void	|simplify_sort	|NN OP *o
 s	|const char*	|gv_ename	|NN GV *gv
-s	|bool	|scalar_mod_type|NN const OP *o|I32 type
+sRn	|bool	|scalar_mod_type|NN const OP *o|I32 type
 s	|OP *	|my_kid		|NULLOK OP *o|NULLOK OP *attrs|NN OP **imopsp
 s	|OP *	|dup_attrlist	|NN OP *o
 s	|void	|apply_attrs	|NN HV *stash|NN SV *target|NULLOK OP *attrs|bool for_my
@@ -1203,7 +1203,7 @@ s	|void	|save_lines	|NULLOK AV *array|NN SV *sv
 sR	|OP*	|doeval		|int gimme|NULLOK OP** startop|NULLOK CV* outside|U32 seq
 sR	|PerlIO *|check_type_and_open|NN const char *name|NN const char *mode
 sR	|PerlIO *|doopen_pm	|NN const char *name|NN const char *mode
-sR	|bool	|path_is_absolute|NN const char *name
+sRn	|bool	|path_is_absolute|NN const char *name
 sR	|I32	|run_user_filter|int idx|NN SV *buf_sv|int maxlen
 sR	|PMOP*	|make_matcher	|NN regexp* re
 sR	|bool	|matcher_matches_sv|NN PMOP* matcher|NN SV* sv
@@ -1244,13 +1244,13 @@ Es	|regnode*|regatom	|NN struct RExC_state_t *state|NN I32 *flagp
 Es	|regnode*|regbranch	|NN struct RExC_state_t *state|NN I32 *flagp|I32 first
 Es	|void	|reguni		|NN const struct RExC_state_t *state|UV uv|NN char *s|NN STRLEN *lenp
 Es	|regnode*|regclass	|NN struct RExC_state_t *state
-ERs	|I32	|regcurly	|NN const char *
+ERsn	|I32	|regcurly	|NN const char *
 Es	|regnode*|reg_node	|NN struct RExC_state_t *state|U8 op
 Es	|regnode*|regpiece	|NN struct RExC_state_t *state|NN I32 *flagp
 Es	|void	|reginsert	|NN struct RExC_state_t *state|U8 op|NN regnode *opnd
 Es	|void	|regoptail	|NN struct RExC_state_t *state|NN regnode *p|NN regnode *val
 Es	|void	|regtail	|NN struct RExC_state_t *state|NN regnode *p|NN regnode *val
-Es	|char*	|regwhite	|NN char *p|NN const char *e
+EsRn	|char*	|regwhite	|NN char *p|NN const char *e
 Es	|char*	|nextchar	|NN struct RExC_state_t *state
 #  ifdef DEBUGGING
 Es	|regnode*|dumpuntil	|NN regnode *start|NN regnode *node \
@@ -1258,18 +1258,18 @@ Es	|regnode*|dumpuntil	|NN regnode *start|NN regnode *node \
 Es	|void	|put_byte	|NN SV* sv|int c
 #  endif
 Es	|void	|scan_commit	|NN struct RExC_state_t* state|NN struct scan_data_t *data
-Es	|void	|cl_anything	|NN struct RExC_state_t* state|NN struct regnode_charclass_class *cl
-Es	|int	|cl_is_anything	|NN const struct regnode_charclass_class *cl
-Es	|void	|cl_init	|NN struct RExC_state_t* state|NN struct regnode_charclass_class *cl
-Es	|void	|cl_init_zero	|NN struct RExC_state_t* state|NN struct regnode_charclass_class *cl
-Es	|void	|cl_and		|NN struct regnode_charclass_class *cl \
+Esn	|void	|cl_anything	|NN struct RExC_state_t* state|NN struct regnode_charclass_class *cl
+EsRn	|int	|cl_is_anything	|NN const struct regnode_charclass_class *cl
+Esn	|void	|cl_init	|NN struct RExC_state_t* state|NN struct regnode_charclass_class *cl
+Esn	|void	|cl_init_zero	|NN struct RExC_state_t* state|NN struct regnode_charclass_class *cl
+Esn	|void	|cl_and		|NN struct regnode_charclass_class *cl \
 				|NN const struct regnode_charclass_class *and_with
-Es	|void	|cl_or		|NN struct RExC_state_t* state|NN struct regnode_charclass_class *cl \
+Esn	|void	|cl_or		|NN struct RExC_state_t* state|NN struct regnode_charclass_class *cl \
 				|NN const struct regnode_charclass_class *or_with
 Es	|I32	|study_chunk	|NN struct RExC_state_t* state|NN regnode **scanp \
 				|NN I32 *deltap|NN regnode *last|NULLOK struct scan_data_t *data \
 				|U32 flags|U32 depth
-Es	|I32	|add_data	|NN struct RExC_state_t* state|I32 n|NN const char *s
+EsRn	|I32	|add_data	|NN struct RExC_state_t* state|I32 n|NN const char *s
 rs	|void	|re_croak2	|NN const char* pat1|NN const char* pat2|...
 Es	|I32	|regpposixcc	|NN struct RExC_state_t* state|I32 value
 Es	|void	|checkposixcc	|NN struct RExC_state_t* state
@@ -1290,9 +1290,9 @@ Es	|CHECKPOINT|regcppush	|I32 parenfloor
 Es	|char*|regcppop
 Es	|void	|cache_re	|NN regexp *prog
 ERs	|U8*	|reghop		|NN U8 *pos|I32 off
-ERs	|U8*	|reghop3	|NN U8 *pos|I32 off|NN U8 *lim
+ERsn	|U8*	|reghop3	|NN U8 *pos|I32 off|NN U8 *lim
 ERs	|U8*	|reghopmaybe	|NN U8 *pos|I32 off
-ERs	|U8*	|reghopmaybe3	|NN U8 *pos|I32 off|NN U8 *lim
+ERsn	|U8*	|reghopmaybe3	|NN U8 *pos|I32 off|NN U8 *lim
 ERs	|char*	|find_byclass	|NN regexp * prog|NN regnode *c|NN char *s|NN const char *strend|I32 norun
 Es	|void	|to_utf8_substr	|NN regexp * prog
 Es	|void	|to_byte_substr	|NN regexp * prog
@@ -1342,9 +1342,18 @@ s	|bool	|utf8_mg_pos_init	|NN SV *sv|NN MAGIC **mgp \
 				|NN const U8 *s|NN const U8 *start
 s	|char *	|stringify_regexp|NN SV *sv|NN MAGIC *mg|NULLOK STRLEN *lp
 sn	|char *	|F0convert	|NV nv|NN char *endbuf|NN STRLEN *len
-#if defined(PERL_OLD_COPY_ON_WRITE)
+#  if defined(PERL_OLD_COPY_ON_WRITE)
 sM	|void	|sv_release_COW	|NN SV *sv|NN const char *pvx|STRLEN len|NN SV *after
-#endif
+#  endif
+s	|SV *	|more_sv
+s	|void *	|more_bodies	|size_t size|svtype sv_type
+s	|bool	|sv_2iuv_common	|NN SV *sv
+s	|void	|glob_assign_glob|NN SV *dstr|NN SV *sstr|const int dtype
+s	|void	|glob_assign_ref|NN SV *dstr|NN SV *sstr
+sRn	|PTR_TBL_ENT_t *|ptr_table_find|NN PTR_TBL_t *tbl|NN const void *sv
+s	|SV *	|find_hash_subscript|NULLOK HV *hv|NN SV *val
+s	|I32	|find_array_subscript|NULLOK AV *av|NN SV *val
+s	|SV *	|find_uninit_var|NULLOK OP *obase|NULLOK SV *uninit_sv|bool match
 #endif
 
 #if defined(PERL_IN_TOKE_C) || defined(PERL_DECL_PROT)
@@ -1409,7 +1418,7 @@ s	|char*	|stdize_locale	|NN char* locs
 #endif
 
 #if defined(PERL_IN_UTIL_C) || defined(PERL_DECL_PROT)
-s	|COP*	|closest_cop	|NN COP *cop|NULLOK const OP *o
+s	|const COP*|closest_cop	|NN const COP *cop|NULLOK const OP *o
 s	|SV*	|mess_alloc
 s	|const char *|vdie_croak_common|NULLOK const char *pat|NULLOK va_list *args \
 				|NULLOK STRLEN *msglen|NULLOK I32* utf8
@@ -1423,7 +1432,7 @@ sn	|NV|mulexp10	|NV value|I32 exponent
 #endif
 
 #if defined(PERL_IN_UTF8_C) || defined(PERL_DECL_PROT)
-s	|STRLEN	|is_utf8_char_slow|NN const U8 *s|const STRLEN len
+sRn	|STRLEN	|is_utf8_char_slow|NN const U8 *s|const STRLEN len
 sR	|bool	|is_utf8_common	|NN const U8 *const p|NN SV **swash|NN const char * const swashname
 sR	|SV*	|swash_get	|NN SV* swash|UV start|UV span
 #endif
diff --git a/hv.c b/hv.c
index ca509aa62a..061d0ce62f 100644
--- a/hv.c
+++ b/hv.c
@@ -91,7 +91,7 @@ S_new_he(pTHX)
 #endif
 
 STATIC HEK *
-S_save_hek_flags(pTHX_ const char *str, I32 len, U32 hash, int flags)
+S_save_hek_flags(const char *str, I32 len, U32 hash, int flags)
 {
     const int flags_masked = flags & HVhek_MASK;
     char *k;
@@ -857,7 +857,7 @@ S_hv_fetch_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen,
 }
 
 STATIC void
-S_hv_magic_check(pTHX_ HV *hv, bool *needs_copy, bool *needs_store)
+S_hv_magic_check(HV *hv, bool *needs_copy, bool *needs_store)
 {
     const MAGIC *mg = SvMAGIC(hv);
     *needs_copy = FALSE;
@@ -1820,7 +1820,7 @@ Perl_hv_undef(pTHX_ HV *hv)
 }
 
 static struct xpvhv_aux*
-S_hv_auxinit(pTHX_ HV *hv) {
+S_hv_auxinit(HV *hv) {
     struct xpvhv_aux *iter;
     char *array;
 
diff --git a/mg.c b/mg.c
index 2de5a86504..6446b2cc52 100644
--- a/mg.c
+++ b/mg.c
@@ -354,7 +354,7 @@ Perl_mg_find(pTHX_ const SV *sv, int type)
                 return mg;
         }
     }
-    return 0;
+    return NULL;
 }
 
 /*
diff --git a/op.c b/op.c
index 32927d33c6..9580c64865 100644
--- a/op.c
+++ b/op.c
@@ -146,14 +146,14 @@ Perl_Slab_Free(pTHX_ void *op)
 }
 #endif
 /*
- * In the following definition, the ", Nullop" is just to make the compiler
+ * In the following definition, the ", NULL" is just to make the compiler
  * think the expression is of the right type: croak actually does a Siglongjmp.
  */
 #define CHECKOP(type,o) \
     ((PL_op_mask && PL_op_mask[type])					\
      ? ( op_free((OP*)o),					\
 	 Perl_croak(aTHX_ "'%s' trapped by operation mask", PL_op_desc[type]),	\
-	 Nullop )						\
+	 NULL )						\
      : CALL_FPTR(PL_check[type])(aTHX_ (OP*)o))
 
 #define RETURN_UNLIMITED_NUMBER (PERL_INT_MAX / 2)
@@ -316,7 +316,7 @@ Perl_op_free(pTHX_ OP *o)
     FreeOp(o);
 #ifdef DEBUG_LEAKING_SCALARS
     if (PL_op == o)
-	PL_op = Nullop;
+	PL_op = NULL;
 #endif
 }
 
@@ -426,7 +426,7 @@ clear_pmop:
 	    }
 	    PmopSTASH_free(cPMOPo);
 	}
-	cPMOPo->op_pmreplroot = Nullop;
+	cPMOPo->op_pmreplroot = NULL;
         /* we use the "SAFE" version of the PM_ macros here
          * since sv_clean_all might release some PMOPs
          * after PL_regex_padav has been cleared
@@ -434,7 +434,7 @@ clear_pmop:
          * happen before sv_clean_all
          */
 	ReREFCNT_dec(PM_GETRE_SAFE(cPMOPo));
-	PM_SETRE_SAFE(cPMOPo, (REGEXP*)NULL);
+	PM_SETRE_SAFE(cPMOPo, NULL);
 #ifdef USE_ITHREADS
 	if(PL_regex_pad) {        /* We could be in destruction */
             av_push((AV*) PL_regex_pad[0],(SV*) PL_regex_pad[(cPMOPo)->op_pmoffset]);
@@ -1104,7 +1104,7 @@ Perl_mod(pTHX_ OP *o, I32 type)
 			NewOp(1101, newop, 1, UNOP);
 			newop->op_type = OP_RV2CV;
 			newop->op_ppaddr = PL_ppaddr[OP_RV2CV];
-			newop->op_first = Nullop;
+			newop->op_first = NULL;
                         newop->op_next = (OP*)newop;
 			kid->op_sibling = (OP*)newop;
 			newop->op_private |= OPpLVAL_INTRO;
@@ -1138,7 +1138,7 @@ Perl_mod(pTHX_ OP *o, I32 type)
 			kid->op_next = okid;
 		    }
 		    else
-			okid->op_next = Nullop;
+			okid->op_next = NULL;
 		    okid->op_type = OP_RV2CV;
 		    okid->op_targ = 0;
 		    okid->op_ppaddr = PL_ppaddr[OP_RV2CV];
@@ -1362,7 +1362,7 @@ Perl_mod(pTHX_ OP *o, I32 type)
 }
 
 STATIC bool
-S_scalar_mod_type(pTHX_ const OP *o, I32 type)
+S_scalar_mod_type(const OP *o, I32 type)
 {
     switch (type) {
     case OP_SASSIGN:
@@ -1409,7 +1409,7 @@ S_scalar_mod_type(pTHX_ const OP *o, I32 type)
 }
 
 STATIC bool
-S_is_handle_constructor(pTHX_ const OP *o, I32 numargs)
+S_is_handle_constructor(const OP *o, I32 numargs)
 {
     switch (o->op_type) {
     case OP_PIPE_OP:
@@ -1425,7 +1425,7 @@ S_is_handle_constructor(pTHX_ const OP *o, I32 numargs)
     case OP_ACCEPT:
 	if (numargs == 1)
 	    return TRUE;
-	/* FALL THROUGH */
+	/* FALLTHROUGH */
     default:
 	return FALSE;
     }
@@ -1551,7 +1551,7 @@ S_dup_attrlist(pTHX_ OP *o)
 	rop = newSVOP(OP_CONST, o->op_flags, SvREFCNT_inc(cSVOPo->op_sv));
     else {
 	assert((o->op_type == OP_LIST) && (o->op_flags & OPf_KIDS));
-	rop = Nullop;
+	rop = NULL;
 	for (o = cLISTOPo->op_first; o; o=o->op_sibling) {
 	    if (o->op_type == OP_CONST)
 		rop = append_elem(OP_LIST, rop,
@@ -1664,7 +1664,7 @@ void
 Perl_apply_attrs_string(pTHX_ const char *stashpv, CV *cv,
                         const char *attrstr, STRLEN len)
 {
-    OP *attrs = Nullop;
+    OP *attrs = NULL;
 
     if (!len) {
         len = strlen(attrstr);
@@ -1772,7 +1772,7 @@ Perl_my_attrs(pTHX_ OP *o, OP *attrs)
 #endif
     if (attrs)
 	SAVEFREEOP(attrs);
-    rops = Nullop;
+    rops = NULL;
     o = my_kid(o, attrs, &rops);
     if (rops) {
 	if (maybe_scalar && o->op_type == OP_PADSV) {
@@ -1790,7 +1790,7 @@ Perl_my_attrs(pTHX_ OP *o, OP *attrs)
 OP *
 Perl_my(pTHX_ OP *o)
 {
-    return my_attrs(o, Nullop);
+    return my_attrs(o, NULL);
 }
 
 OP *
@@ -1892,7 +1892,7 @@ Perl_scope(pTHX_ OP *o)
 	    }
 	}
 	else
-	    o = newLISTOP(OP_SCOPE, 0, o, Nullop);
+	    o = newLISTOP(OP_SCOPE, 0, o, NULL);
     }
     return o;
 }
@@ -2174,7 +2174,7 @@ Perl_convert(pTHX_ I32 type, I32 flags, OP *o)
 {
     dVAR;
     if (!o || o->op_type != OP_LIST)
-	o = newLISTOP(OP_LIST, 0, o, Nullop);
+	o = newLISTOP(OP_LIST, 0, o, NULL);
     else
 	o->op_flags &= ~OPf_WANT;
 
@@ -2286,7 +2286,7 @@ OP *
 Perl_force_list(pTHX_ OP *o)
 {
     if (!o || o->op_type != OP_LIST)
-	o = newLISTOP(OP_LIST, 0, o, Nullop);
+	o = newLISTOP(OP_LIST, 0, o, NULL);
     op_null(o);
     return o;
 }
@@ -2400,7 +2400,10 @@ Perl_newBINOP(pTHX_ I32 type, I32 flags, OP *first, OP *last)
     return fold_constants((OP *)binop);
 }
 
-static int uvcompare(const void *a, const void *b) __attribute__nonnull__(1) __attribute__nonnull__(2) __attribute__pure__;
+static int uvcompare(const void *a, const void *b)
+    __attribute__nonnull__(1)
+    __attribute__nonnull__(2)
+    __attribute__pure__;
 static int uvcompare(const void *a, const void *b)
 {
     if (*((const UV *)a) < (*(const UV *)b))
@@ -2785,7 +2788,7 @@ Perl_pmruntime(pTHX_ OP *o, OP *expr, bool isreg)
     PMOP *pm;
     LOGOP *rcop;
     I32 repl_has_vars = 0;
-    OP* repl  = Nullop;
+    OP* repl = NULL;
     bool reglist;
 
     if (o->op_type == OP_SUBST || o->op_type == OP_TRANS) {
@@ -2795,7 +2798,7 @@ Perl_pmruntime(pTHX_ OP *o, OP *expr, bool isreg)
 	kid = cLISTOPx(expr)->op_first;
 	while (kid->op_sibling != repl)
 	    kid = kid->op_sibling;
-	kid->op_sibling = Nullop;
+	kid->op_sibling = NULL;
 	cLISTOPx(expr)->op_last = kid;
     }
 
@@ -2805,8 +2808,8 @@ Perl_pmruntime(pTHX_ OP *o, OP *expr, bool isreg)
 	/* convert single element list to element */
 	OP* const oe = expr;
 	expr = cLISTOPx(oe)->op_first->op_sibling;
-	cLISTOPx(oe)->op_first->op_sibling = Nullop;
-	cLISTOPx(oe)->op_last = Nullop;
+	cLISTOPx(oe)->op_first->op_sibling = NULL;
+	cLISTOPx(oe)->op_last = NULL;
 	op_free(oe);
     }
 
@@ -3066,7 +3069,7 @@ Perl_utilize(pTHX_ int aver, I32 floor, OP *version, OP *idop, OP *arg)
     if (idop->op_type != OP_CONST)
 	Perl_croak(aTHX_ "Module name must be constant");
 
-    veop = Nullop;
+    veop = NULL;
 
     if (version) {
 	SV * const vesv = ((SVOP*)version)->op_sv;
@@ -3097,7 +3100,7 @@ Perl_utilize(pTHX_ int aver, I32 floor, OP *version, OP *idop, OP *arg)
     if (arg && arg->op_type == OP_STUB)
 	imop = arg;		/* no import on explicit () */
     else if (SvNIOKp(((SVOP*)idop)->op_sv)) {
-	imop = Nullop;		/* use 5.0; */
+	imop = NULL;		/* use 5.0; */
 	if (!aver)
 	    idop->op_private |= OPpCONST_NOVER;
     }
@@ -3119,8 +3122,8 @@ Perl_utilize(pTHX_ int aver, I32 floor, OP *version, OP *idop, OP *arg)
     /* Fake up the BEGIN {}, which does its thing immediately. */
     newATTRSUB(floor,
 	newSVOP(OP_CONST, 0, newSVpvs_share("BEGIN")),
-	Nullop,
-	Nullop,
+	NULL,
+	NULL,
 	append_elem(OP_LINESEQ,
 	    append_elem(OP_LINESEQ,
 	        newSTATEOP(0, NULL, newUNOP(OP_REQUIRE, 0, idop)),
@@ -3199,7 +3202,7 @@ Perl_vload_module(pTHX_ U32 flags, SV *name, SV *ver, va_list *args)
 	veop = newSVOP(OP_CONST, 0, ver);
     }
     else
-	veop = Nullop;
+	veop = NULL;
     if (flags & PERL_LOADMOD_NOIMPORT) {
 	imop = sawparens(newNULLLIST());
     }
@@ -3208,7 +3211,7 @@ Perl_vload_module(pTHX_ U32 flags, SV *name, SV *ver, va_list *args)
     }
     else {
 	SV *sv;
-	imop = Nullop;
+	imop = NULL;
 	sv = va_arg(*args, SV*);
 	while (sv) {
 	    imop = append_elem(OP_LIST, imop, newSVOP(OP_CONST, 0, sv));
@@ -3427,7 +3430,7 @@ Perl_newASSIGNOP(pTHX_ I32 flags, OP *left, I32 optype, OP *right)
 			pm->op_pmflags |= PMf_ONCE;
 			tmpop = cUNOPo->op_first;	/* to list (nulled) */
 			tmpop = ((UNOP*)tmpop)->op_first; /* to pushmark */
-			tmpop->op_sibling = Nullop;	/* don't free split */
+			tmpop->op_sibling = NULL;	/* don't free split */
 			right->op_next = tmpop->op_next;  /* fix starting loc */
 			op_free(o);			/* blow off assign */
 			right->op_flags &= ~OPf_WANT;
@@ -3563,7 +3566,7 @@ S_new_logop(pTHX_ I32 type, I32 flags, OP** firstp, OP** otherp)
 	    first = *firstp = cUNOPo->op_first;
 	    if (o->op_next)
 		first->op_next = o->op_next;
-	    cUNOPo->op_first = Nullop;
+	    cUNOPo->op_first = NULL;
 	    op_free(o);
 	}
     }
@@ -3576,7 +3579,7 @@ S_new_logop(pTHX_ I32 type, I32 flags, OP** firstp, OP** otherp)
 	    (type == OP_OR  && !SvTRUE(((SVOP*)first)->op_sv)) ||
 	    (type == OP_DOR && !SvOK(((SVOP*)first)->op_sv))) {
 	    op_free(first);
-	    *firstp = Nullop;
+	    *firstp = NULL;
 	    if (other->op_type == OP_CONST)
 		other->op_private |= OPpCONST_SHORTCIRCUIT;
 	    return other;
@@ -3600,7 +3603,7 @@ S_new_logop(pTHX_ I32 type, I32 flags, OP** firstp, OP** otherp)
 	    }
 
 	    op_free(other);
-	    *otherp = Nullop;
+	    *otherp = NULL;
 	    if (first->op_type == OP_CONST)
 		first->op_private |= OPpCONST_SHORTCIRCUIT;
 	    return first;
@@ -3905,7 +3908,7 @@ whileline, OP *expr, OP *block, OP *cont, I32 has_my)
 	if (o == expr && o->op_type == OP_CONST && !SvTRUE(cSVOPo->op_sv)) {
 	    op_free(expr);		/* oops, it's a while (0) */
 	    op_free((OP*)loop);
-	    return Nullop;		/* listop already freed by new_logop */
+	    return NULL;		/* listop already freed by new_logop */
 	}
 	if (listop)
 	    ((LISTOP*)listop)->op_last->op_next =
@@ -3961,14 +3964,14 @@ Perl_newFOROP(pTHX_ I32 flags, char *label, line_t forline, OP *sv, OP *expr, OP
 	    padoff = sv->op_targ;
 	    sv->op_targ = 0;
 	    op_free(sv);
-	    sv = Nullop;
+	    sv = NULL;
 	}
 	else if (sv->op_type == OP_THREADSV) { /* per-thread variable */
 	    padoff = sv->op_targ;
 	    sv->op_targ = 0;
 	    iterflags |= OPf_SPECIAL;
 	    op_free(sv);
-	    sv = Nullop;
+	    sv = NULL;
 	}
 	else
 	    Perl_croak(aTHX_ "Can't use %s for loop variable", PL_op_desc[sv->op_type]);
@@ -4004,7 +4007,7 @@ Perl_newFOROP(pTHX_ I32 flags, char *label, line_t forline, OP *sv, OP *expr, OP
 	LISTOP* listop;
 
 	range->op_flags &= ~OPf_KIDS;
-	range->op_first = Nullop;
+	range->op_first = NULL;
 
 	listop = (LISTOP*)newLISTOP(OP_LIST, 0, left, right);
 	listop->op_first->op_next = range->op_next;
@@ -4277,8 +4280,8 @@ Perl_cv_undef(pTHX_ CV *cv)
 	PAD_SAVE_SETNULLPAD();
 
 	op_free(CvROOT(cv));
-	CvROOT(cv) = Nullop;
-	CvSTART(cv) = Nullop;
+	CvROOT(cv) = NULL;
+	CvSTART(cv) = NULL;
 	LEAVE;
     }
     SvPOK_off((SV*)cv);		/* forget prototype */
@@ -4450,7 +4453,7 @@ Perl_newMYSUB(pTHX_ I32 floor, OP *o, OP *proto, OP *attrs, OP *block)
 CV *
 Perl_newSUB(pTHX_ I32 floor, OP *o, OP *proto, OP *block)
 {
-    return Perl_newATTRSUB(aTHX_ floor, o, proto, Nullop, block);
+    return Perl_newATTRSUB(aTHX_ floor, o, proto, NULL, block);
 }
 
 CV *
@@ -4667,7 +4670,7 @@ Perl_newATTRSUB(pTHX_ I32 floor, OP *o, OP *proto, OP *attrs, OP *block)
 
     if (PL_error_count) {
 	op_free(block);
-	block = Nullop;
+	block = NULL;
 	if (name) {
 	    const char *s = strrchr(name, ':');
 	    s = s ? s+1 : name;
@@ -5030,7 +5033,7 @@ Perl_newANONHASH(pTHX_ OP *o)
 OP *
 Perl_newANONSUB(pTHX_ I32 floor, OP *proto, OP *block)
 {
-    return newANONATTRSUB(floor, proto, Nullop, block);
+    return newANONATTRSUB(floor, proto, NULL, block);
 }
 
 OP *
@@ -5449,7 +5452,7 @@ Perl_ck_rvconst(pTHX_ register OP *o)
 		o->op_private &= ~HINT_STRICT_REFS;
 	}
 	if ((o->op_private & HINT_STRICT_REFS) && (kid->op_private & OPpCONST_BARE)) {
-            const char *badthing = NULL;
+	    const char *badthing;
 	    switch (o->op_type) {
 	    case OP_RV2SV:
 		badthing = "a SCALAR";
@@ -5460,6 +5463,9 @@ Perl_ck_rvconst(pTHX_ register OP *o)
 	    case OP_RV2HV:
 		badthing = "a HASH";
 		break;
+	    default:
+		badthing = NULL;
+		break;
 	    }
 	    if (badthing)
 		Perl_croak(aTHX_
@@ -6030,7 +6036,7 @@ Perl_ck_smartmatch(pTHX_ OP *o)
 	OP *second = first->op_sibling;
 	
 	/* Implicitly take a reference to an array or hash */
-	first->op_sibling = Nullop;
+	first->op_sibling = NULL;
 	first = cBINOPo->op_first = ref_array_or_hash(first);
 	second = first->op_sibling = ref_array_or_hash(second);
 	
@@ -6570,9 +6576,9 @@ Perl_ck_subr(pTHX_ OP *o)
 	if (o2->op_type == OP_CONST)
 	    o2->op_private &= ~OPpCONST_STRICT;
 	else if (o2->op_type == OP_LIST) {
-	    OP * const o = ((UNOP*)o2)->op_first->op_sibling;
-	    if (o && o->op_type == OP_CONST)
-		o->op_private &= ~OPpCONST_STRICT;
+	    OP * const sib = ((UNOP*)o2)->op_first->op_sibling;
+	    if (sib && sib->op_type == OP_CONST)
+		sib->op_private &= ~OPpCONST_STRICT;
 	}
     }
     o->op_private |= (PL_hints & HINT_STRICT_REFS);
diff --git a/op.h b/op.h
index 4e4aa47d7f..cbf86a085e 100644
--- a/op.h
+++ b/op.h
@@ -522,7 +522,7 @@ struct loop {
 #endif
 
 #define OpREFCNT_set(o,n)		((o)->op_targ = (n))
-#define OpREFCNT_inc(o)			((o) ? (++(o)->op_targ, (o)) : Nullop)
+#define OpREFCNT_inc(o)			((o) ? (++(o)->op_targ, (o)) : NULL)
 #define OpREFCNT_dec(o)			(--(o)->op_targ)
 
 /* flags used by Perl_load_module() */
diff --git a/perl.c b/perl.c
index 3a17b4882a..48757b9da5 100644
--- a/perl.c
+++ b/perl.c
@@ -729,9 +729,9 @@ perl_destruct(pTHXx)
 	    PAD_SET_CUR_NOSAVE(CvPADLIST(PL_main_cv), 1);
 	}
 	op_free(PL_main_root);
-	PL_main_root = Nullop;
+	PL_main_root = NULL;
     }
-    PL_main_start = Nullop;
+    PL_main_start = NULL;
     SvREFCNT_dec(PL_main_cv);
     PL_main_cv = NULL;
     PL_dirty = TRUE;
@@ -1554,9 +1554,9 @@ setuid perl scripts securely.\n");
 
     if (PL_main_root) {
 	op_free(PL_main_root);
-	PL_main_root = Nullop;
+	PL_main_root = NULL;
     }
-    PL_main_start = Nullop;
+    PL_main_start = NULL;
     SvREFCNT_dec(PL_main_cv);
     PL_main_cv = NULL;
 
@@ -2420,8 +2420,7 @@ Perl_get_cv(pTHX_ const char *name, I32 create)
     if (create && !GvCVu(gv))
     	return newSUB(start_subparse(FALSE, 0),
 		      newSVOP(OP_CONST, 0, newSVpv(name,0)),
-		      Nullop,
-		      Nullop);
+		      NULL, NULL);
     if (gv)
 	return GvCVu(gv);
     return NULL;
@@ -2524,7 +2523,7 @@ Perl_call_sv(pTHX_ SV *sv, I32 flags)
     }
 
     Zero(&myop, 1, LOGOP);
-    myop.op_next = Nullop;
+    myop.op_next = NULL;
     if (!(flags & G_NOARGS))
 	myop.op_flags |= OPf_STACKED;
     myop.op_flags |= ((flags & G_VOID) ? OPf_WANT_VOID :
@@ -2700,7 +2699,7 @@ Perl_eval_sv(pTHX_ SV *sv, I32 flags)
 
     if (!(flags & G_NOARGS))
 	myop.op_flags = OPf_STACKED;
-    myop.op_next = Nullop;
+    myop.op_next = NULL;
     myop.op_type = OP_ENTEREVAL;
     myop.op_flags |= ((flags & G_VOID) ? OPf_WANT_VOID :
 		      (flags & G_ARRAY) ? OPf_WANT_LIST :
diff --git a/pp.c b/pp.c
index 3a66f73022..d5c2679f44 100644
--- a/pp.c
+++ b/pp.c
@@ -771,7 +771,7 @@ PP(pp_undef)
 	if (cv_const_sv((CV*)sv) && ckWARN(WARN_MISC))
 	    Perl_warner(aTHX_ packWARN(WARN_MISC), "Constant subroutine %s undefined",
 		 CvANON((CV*)sv) ? "(anonymous)" : GvENAME(CvGV((CV*)sv)));
-	/* FALL THROUGH */
+	/* FALLTHROUGH */
     case SVt_PVFM:
 	{
 	    /* let user-undef'd sub keep its identity */
diff --git a/pp_ctl.c b/pp_ctl.c
index 3f0168e836..1ebea195cf 100644
--- a/pp_ctl.c
+++ b/pp_ctl.c
@@ -2730,7 +2730,7 @@ S_docatch(pTHX_ OP *o)
     }
     JMPENV_POP;
     PL_op = oldop;
-    return Nullop;
+    return NULL;
 }
 
 OP *
@@ -2918,11 +2918,11 @@ S_doeval(pTHX_ int gimme, OP** startop, CV* outside, U32 seq)
 
     /* try to compile it */
 
-    PL_eval_root = Nullop;
+    PL_eval_root = NULL;
     PL_error_count = 0;
     PL_curcop = &PL_compiling;
     PL_curcop->cop_arybase = 0;
-    if (saveop && saveop->op_type != OP_REQUIRE && saveop->op_flags & OPf_SPECIAL)
+    if (saveop && (saveop->op_type != OP_REQUIRE) && (saveop->op_flags & OPf_SPECIAL))
 	PL_in_eval |= EVAL_KEEPERR;
     else
 	sv_setpvn(ERRSV,"",0);
@@ -2935,7 +2935,7 @@ S_doeval(pTHX_ int gimme, OP** startop, CV* outside, U32 seq)
 	PL_op = saveop;
 	if (PL_eval_root) {
 	    op_free(PL_eval_root);
-	    PL_eval_root = Nullop;
+	    PL_eval_root = NULL;
 	}
 	SP = PL_stack_base + POPMARK;		/* pop original mark */
 	if (!startop) {
@@ -4570,7 +4570,7 @@ S_run_user_filter(pTHX_ int idx, SV *buf_sv, int maxlen)
 /* perhaps someone can come up with a better name for
    this?  it is not really "absolute", per se ... */
 static bool
-S_path_is_absolute(pTHX_ const char *name)
+S_path_is_absolute(const char *name)
 {
     if (PERL_FILE_IS_ABSOLUTE(name)
 #ifdef MACOS_TRADITIONAL
diff --git a/pp_sort.c b/pp_sort.c
index 3ea07d57a0..48595886cb 100644
--- a/pp_sort.c
+++ b/pp_sort.c
@@ -1536,7 +1536,7 @@ PP(pp_sort)
 	}
     }
     else {
-	PL_sortcop = Nullop;
+	PL_sortcop = NULL;
 	stash = CopSTASH(PL_curcop);
     }
 
diff --git a/regcomp.c b/regcomp.c
index 5d9fb63e53..625479cc99 100644
--- a/regcomp.c
+++ b/regcomp.c
@@ -487,7 +487,7 @@ S_scan_commit(pTHX_ RExC_state_t *pRExC_state, scan_data_t *data)
 
 /* Can match anything (initialization) */
 STATIC void
-S_cl_anything(pTHX_ RExC_state_t *pRExC_state, struct regnode_charclass_class *cl)
+S_cl_anything(RExC_state_t *pRExC_state, struct regnode_charclass_class *cl)
 {
     ANYOF_CLASS_ZERO(cl);
     ANYOF_BITMAP_SETALL(cl);
@@ -498,7 +498,7 @@ S_cl_anything(pTHX_ RExC_state_t *pRExC_state, struct regnode_charclass_class *c
 
 /* Can match anything (initialization) */
 STATIC int
-S_cl_is_anything(pTHX_ const struct regnode_charclass_class *cl)
+S_cl_is_anything(const struct regnode_charclass_class *cl)
 {
     int value;
 
@@ -514,7 +514,7 @@ S_cl_is_anything(pTHX_ const struct regnode_charclass_class *cl)
 
 /* Can match anything (initialization) */
 STATIC void
-S_cl_init(pTHX_ RExC_state_t *pRExC_state, struct regnode_charclass_class *cl)
+S_cl_init(RExC_state_t *pRExC_state, struct regnode_charclass_class *cl)
 {
     Zero(cl, 1, struct regnode_charclass_class);
     cl->type = ANYOF;
@@ -522,7 +522,7 @@ S_cl_init(pTHX_ RExC_state_t *pRExC_state, struct regnode_charclass_class *cl)
 }
 
 STATIC void
-S_cl_init_zero(pTHX_ RExC_state_t *pRExC_state, struct regnode_charclass_class *cl)
+S_cl_init_zero(RExC_state_t *pRExC_state, struct regnode_charclass_class *cl)
 {
     Zero(cl, 1, struct regnode_charclass_class);
     cl->type = ANYOF;
@@ -534,7 +534,7 @@ S_cl_init_zero(pTHX_ RExC_state_t *pRExC_state, struct regnode_charclass_class *
 /* 'And' a given class with another one.  Can create false positives */
 /* We assume that cl is not inverted */
 STATIC void
-S_cl_and(pTHX_ struct regnode_charclass_class *cl,
+S_cl_and(struct regnode_charclass_class *cl,
 	const struct regnode_charclass_class *and_with)
 {
     if (!(and_with->flags & ANYOF_CLASS)
@@ -571,7 +571,7 @@ S_cl_and(pTHX_ struct regnode_charclass_class *cl,
 /* 'OR' a given class with another one.  Can create false positives */
 /* We assume that cl is not inverted */
 STATIC void
-S_cl_or(pTHX_ RExC_state_t *pRExC_state, struct regnode_charclass_class *cl, const struct regnode_charclass_class *or_with)
+S_cl_or(RExC_state_t *pRExC_state, struct regnode_charclass_class *cl, const struct regnode_charclass_class *or_with)
 {
     if (or_with->flags & ANYOF_INVERT) {
 	/* We do not use
@@ -2725,7 +2725,7 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state, regnode **scanp, I32 *deltap,
 }
 
 STATIC I32
-S_add_data(pTHX_ RExC_state_t *pRExC_state, I32 n, const char *s)
+S_add_data(RExC_state_t *pRExC_state, I32 n, const char *s)
 {
     if (RExC_rx->data) {
 	Renewc(RExC_rx->data,
@@ -4413,7 +4413,7 @@ tryagain:
 }
 
 STATIC char *
-S_regwhite(pTHX_ char *p, const char *e)
+S_regwhite(char *p, const char *e)
 {
     while (p < e) {
 	if (isSPACE(*p))
@@ -5415,7 +5415,6 @@ S_regclass(pTHX_ RExC_state_t *pRExC_state)
 STATIC char*
 S_nextchar(pTHX_ RExC_state_t *pRExC_state)
 {
-    dVAR;
     char* retval = RExC_parse++;
 
     for (;;) {
@@ -5641,7 +5640,7 @@ S_regoptail(pTHX_ RExC_state_t *pRExC_state, regnode *p, regnode *val)
  - regcurly - a little FSA that accepts {\d+,?\d*}
  */
 STATIC I32
-S_regcurly(pTHX_ register const char *s)
+S_regcurly(register const char *s)
 {
     if (*s++ != '{')
 	return FALSE;
diff --git a/regexec.c b/regexec.c
index e374871ab6..919a12b9da 100644
--- a/regexec.c
+++ b/regexec.c
@@ -3466,7 +3466,7 @@ S_regmatch(pTHX_ regnode *prog)
 		PL_regcc = cc.oldcc;
 		saySAME(n);
 	    }
-	    /* NOT REACHED */
+	    /* NOTREACHED */
 	case WHILEM: {
 		/*
 		 * This is really hard to understand, because after we match
@@ -3667,7 +3667,7 @@ S_regmatch(pTHX_ regnode *prog)
 		cc->lastloc = lastloc;
 		CACHEsayNO;
 	    }
-	    /* NOT REACHED */
+	    /* NOTREACHED */
 	case BRANCHJ:
 	    next = scan + ARG(scan);
 	    if (next == scan)
@@ -3855,6 +3855,7 @@ S_regmatch(pTHX_ regnode *prog)
 		}
 	    }
 	    sayNO;
+	    /* NOTREACHED */
 	    break;
 	}
 	case CURLYN:
@@ -4330,11 +4331,11 @@ do_no:
 
 	    goto reenter;
 	}
-	/* NOT REACHED */
+	/* NOTREACHED */
 	default:
 	    Perl_croak(aTHX_ "regexp unwind memory corruption");
 	}
-	/* NOT REACHED */
+	/* NOTREACHED */
     }
 #ifdef DEBUGGING
     PL_regindent--;
@@ -4827,11 +4828,11 @@ STATIC U8 *
 S_reghop(pTHX_ U8 *s, I32 off)
 {
     dVAR;
-    return S_reghop3(aTHX_ s, off, (U8*)(off >= 0 ? PL_regeol : PL_bostr));
+    return S_reghop3(s, off, (U8*)(off >= 0 ? PL_regeol : PL_bostr));
 }
 
 STATIC U8 *
-S_reghop3(pTHX_ U8 *s, I32 off, U8* lim)
+S_reghop3(U8 *s, I32 off, U8* lim)
 {
     dVAR;
     if (off >= 0) {
@@ -4859,11 +4860,11 @@ STATIC U8 *
 S_reghopmaybe(pTHX_ U8 *s, I32 off)
 {
     dVAR;
-    return S_reghopmaybe3(aTHX_ s, off, (U8*)(off >= 0 ? PL_regeol : PL_bostr));
+    return S_reghopmaybe3(s, off, (U8*)(off >= 0 ? PL_regeol : PL_bostr));
 }
 
 STATIC U8 *
-S_reghopmaybe3(pTHX_ U8* s, I32 off, U8* lim)
+S_reghopmaybe3(U8* s, I32 off, U8* lim)
 {
     dVAR;
     if (off >= 0) {
diff --git a/sv.c b/sv.c
index 9c379b8638..a26c14a952 100644
--- a/sv.c
+++ b/sv.c
@@ -3305,7 +3305,7 @@ Perl_sv_setsv_flags(pTHX_ SV *dstr, register SV *sstr, I32 flags)
 	    S_glob_assign_glob(aTHX_ dstr, sstr, dtype);
 	    return;
 	}
-	/* FALL THROUGH */
+	/*FALLTHROUGH*/
 
     default:
 	if (SvGMAGICAL(sstr) && (flags & SV_GMAGIC)) {
@@ -5721,7 +5721,7 @@ Perl_sv_cmp_locale(pTHX_ register SV *sv1, register SV *sv2)
      */
 
   raw_compare:
-    /* FALL THROUGH */
+    /*FALLTHROUGH*/
 
 #endif /* USE_LOCALE_COLLATE */
 
@@ -7032,8 +7032,7 @@ Perl_sv_2cv(pTHX_ SV *sv, HV **st, GV **gvp, I32 lref)
 	     * declaration! */
 	    newSUB(start_subparse(FALSE, 0),
 		   newSVOP(OP_CONST, 0, tmpsv),
-		   Nullop,
-		   Nullop);
+		   NULL, NULL);
 	    LEAVE;
 	    if (!GvCVu(gv))
 		Perl_croak(aTHX_ "Unable to create sub named \"%"SVf"\"",
@@ -7863,7 +7862,7 @@ S_expect_number(pTHX_ char** pattern)
     case '7': case '8': case '9':
 	var = *(*pattern)++ - '0';
 	while (isDIGIT(**pattern)) {
-	    I32 tmp = var * 10 + (*(*pattern)++ - '0');
+	    const I32 tmp = var * 10 + (*(*pattern)++ - '0');
 	    if (tmp < var)
 		Perl_croak(aTHX_ "Integer overflow in format string for %s", (PL_op ? OP_NAME(PL_op) : "sv_vcatpvfn"));
 	    var = tmp;
@@ -8325,7 +8324,7 @@ Perl_sv_vcatpvfn(pTHX_ SV *sv, const char *pat, STRLEN patlen, va_list *args, SV
 #endif
 #if defined(HAS_QUAD) || defined(HAS_LONG_DOUBLE)
 	case 'L':			/* Ld */
-	    /* FALL THROUGH */
+	    /*FALLTHROUGH*/
 #ifdef HAS_QUAD
 	case 'q':			/* qd */
 #endif
@@ -8341,9 +8340,9 @@ Perl_sv_vcatpvfn(pTHX_ SV *sv, const char *pat, STRLEN patlen, va_list *args, SV
 		break;
 	     }
 #endif
-	    /* FALL THROUGH */
+	    /*FALLTHROUGH*/
 	case 'h':
-	    /* FALL THROUGH */
+	    /*FALLTHROUGH*/
 	case 'V':
 	    intsize = *q++;
 	    break;
@@ -8446,7 +8445,7 @@ Perl_sv_vcatpvfn(pTHX_ SV *sv, const char *pat, STRLEN patlen, va_list *args, SV
 #else
 	    intsize = 'l';
 #endif
-	    /* FALL THROUGH */
+	    /*FALLTHROUGH*/
 	case 'd':
 	case 'i':
 #if vdNUMBER
@@ -8512,7 +8511,7 @@ Perl_sv_vcatpvfn(pTHX_ SV *sv, const char *pat, STRLEN patlen, va_list *args, SV
 #else
 	    intsize = 'l';
 #endif
-	    /* FALL THROUGH */
+	    /*FALLTHROUGH*/
 	case 'u':
 	    base = 10;
 	    goto uns_integer;
@@ -8527,7 +8526,7 @@ Perl_sv_vcatpvfn(pTHX_ SV *sv, const char *pat, STRLEN patlen, va_list *args, SV
 #else
 	    intsize = 'l';
 #endif
-	    /* FALL THROUGH */
+	    /*FALLTHROUGH*/
 	case 'o':
 	    base = 8;
 	    goto uns_integer;
@@ -8637,7 +8636,7 @@ Perl_sv_vcatpvfn(pTHX_ SV *sv, const char *pat, STRLEN patlen, va_list *args, SV
 
 	case 'F':
 	    c = 'f';		/* maybe %F isn't supported here */
-	    /* FALL THROUGH */
+	    /*FALLTHROUGH*/
 	case 'e': case 'E':
 	case 'f':
 	case 'g': case 'G':
@@ -8658,7 +8657,7 @@ Perl_sv_vcatpvfn(pTHX_ SV *sv, const char *pat, STRLEN patlen, va_list *args, SV
 		break;
 /* [perl #20339] - we should accept and ignore %lf rather than die */
 	    case 'l':
-		/* FALL THROUGH */
+		/*FALLTHROUGH*/
 	    default:
 #if defined(USE_LONG_DOUBLE)
 		intsize = args ? 0 : 'q';
@@ -8668,7 +8667,7 @@ Perl_sv_vcatpvfn(pTHX_ SV *sv, const char *pat, STRLEN patlen, va_list *args, SV
 #if defined(HAS_LONG_DOUBLE)
 		break;
 #else
-		/* FALL THROUGH */
+		/*FALLTHROUGH*/
 #endif
 	    case 'h':
 		goto unknown;
@@ -9295,7 +9294,7 @@ Perl_ptr_table_new(pTHX)
 /* map an existing pointer using a table */
 
 STATIC PTR_TBL_ENT_t *
-S_ptr_table_find(pTHX_ PTR_TBL_t *tbl, const void *sv) {
+S_ptr_table_find(PTR_TBL_t *tbl, const void *sv) {
     PTR_TBL_ENT_t *tblent;
     const UV hash = PTR_TABLE_HASH(sv);
     assert(tbl);
@@ -9310,7 +9309,7 @@ S_ptr_table_find(pTHX_ PTR_TBL_t *tbl, const void *sv) {
 void *
 Perl_ptr_table_fetch(pTHX_ PTR_TBL_t *tbl, const void *sv)
 {
-    PTR_TBL_ENT_t const *const tblent = S_ptr_table_find(aTHX_ tbl, sv);
+    PTR_TBL_ENT_t const *const tblent = ptr_table_find(tbl, sv);
     return tblent ? tblent->newval : (void *) 0;
 }
 
@@ -9319,7 +9318,7 @@ Perl_ptr_table_fetch(pTHX_ PTR_TBL_t *tbl, const void *sv)
 void
 Perl_ptr_table_store(pTHX_ PTR_TBL_t *tbl, const void *oldsv, void *newsv)
 {
-    PTR_TBL_ENT_t *tblent = S_ptr_table_find(aTHX_ tbl, oldsv);
+    PTR_TBL_ENT_t *tblent = S_ptr_table_find(tbl, oldsv);
 
     if (tblent) {
 	tblent->newval = newsv;
@@ -10093,12 +10092,12 @@ Perl_ss_dup(pTHX_ PerlInterpreter *proto_perl, CLONE_PARAMS* param)
 		    OpREFCNT_inc(o);
 		    break;
 		default:
-		    TOPPTR(nss,ix) = Nullop;
+		    TOPPTR(nss,ix) = NULL;
 		    break;
 		}
 	    }
 	    else
-		TOPPTR(nss,ix) = Nullop;
+		TOPPTR(nss,ix) = NULL;
 	    break;
 	case SAVEt_FREEPV:
 	    c = (char*)POPPTR(ss,ix);
@@ -10314,17 +10313,17 @@ perl_clone_using(PerlInterpreter *proto_perl, UV flags,
 
     IV i;
     CLONE_PARAMS clone_params;
-    CLONE_PARAMS* param = &clone_params;
+    CLONE_PARAMS* const param = &clone_params;
 
-    PerlInterpreter *my_perl = (PerlInterpreter*)(*ipM->pMalloc)(ipM, sizeof(PerlInterpreter));
+    PerlInterpreter * const my_perl = (PerlInterpreter*)(*ipM->pMalloc)(ipM, sizeof(PerlInterpreter));
     /* for each stash, determine whether its objects should be cloned */
     S_visit(proto_perl, do_mark_cloneable_stash, SVt_PVHV, SVTYPEMASK);
     PERL_SET_THX(my_perl);
 
 #  ifdef DEBUGGING
     Poison(my_perl, 1, PerlInterpreter);
-    PL_op = Nullop;
-    PL_curcop = (COP *)Nullop;
+    PL_op = NULL;
+    PL_curcop = NULL;
     PL_markstack = 0;
     PL_scopestack = 0;
     PL_savestack = 0;
@@ -10350,15 +10349,15 @@ perl_clone_using(PerlInterpreter *proto_perl, UV flags,
     IV i;
     CLONE_PARAMS clone_params;
     CLONE_PARAMS* param = &clone_params;
-    PerlInterpreter *my_perl = (PerlInterpreter*)PerlMem_malloc(sizeof(PerlInterpreter));
+    PerlInterpreter * const my_perl = (PerlInterpreter*)PerlMem_malloc(sizeof(PerlInterpreter));
     /* for each stash, determine whether its objects should be cloned */
     S_visit(proto_perl, do_mark_cloneable_stash, SVt_PVHV, SVTYPEMASK);
     PERL_SET_THX(my_perl);
 
 #    ifdef DEBUGGING
     Poison(my_perl, 1, PerlInterpreter);
-    PL_op = Nullop;
-    PL_curcop = (COP *)Nullop;
+    PL_op = NULL;
+    PL_curcop = NULL;
     PL_markstack = 0;
     PL_scopestack = 0;
     PL_savestack = 0;
@@ -10973,7 +10972,7 @@ perl_clone_using(PerlInterpreter *proto_perl, UV flags,
     PL_errors		= sv_dup_inc(proto_perl->Terrors, param);
     PL_hv_fetch_ent_mh	= Nullhe;
     PL_modcount		= proto_perl->Tmodcount;
-    PL_lastgotoprobe	= Nullop;
+    PL_lastgotoprobe	= NULL;
     PL_dumpindent	= proto_perl->Tdumpindent;
 
     PL_sortcop		= (OP*)any_dup(proto_perl->Tsortcop, proto_perl);
@@ -11536,7 +11535,6 @@ S_find_uninit_var(pTHX_ OP* obase, SV* uninit_sv, bool match)
 		? '@' : '%',
 		o->op_targ, NULL, 0, FUV_SUBSCRIPT_WITHIN);
 	}
-
 	break;
 
     case OP_AASSIGN:
@@ -11601,7 +11599,7 @@ S_find_uninit_var(pTHX_ OP* obase, SV* uninit_sv, bool match)
     case OP_CHOMP:
 	if (SvROK(PL_rs) && uninit_sv == SvRV(PL_rs))
 	    return sv_2mortal(newSVpvs("${$/}"));
-	/* FALL THROUGH */
+	/*FALLTHROUGH*/
 
     default:
     do_op:
@@ -11615,7 +11613,7 @@ S_find_uninit_var(pTHX_ OP* obase, SV* uninit_sv, bool match)
 
 	/* if all except one arg are constant, or have no side-effects,
 	 * or are optimized away, then it's unambiguous */
-	o2 = Nullop;
+	o2 = NULL;
 	for (kid=o; kid; kid = kid->op_sibling) {
 	    if (kid &&
 		(    (kid->op_type == OP_CONST && SvOK(cSVOPx_sv(kid)))
@@ -11625,7 +11623,7 @@ S_find_uninit_var(pTHX_ OP* obase, SV* uninit_sv, bool match)
 	    )
 		continue;
 	    if (o2) { /* more than one found */
-		o2 = Nullop;
+		o2 = NULL;
 		break;
 	    }
 	    o2 = kid;
diff --git a/toke.c b/toke.c
index 8f01720491..c5f9c8fe9f 100644
--- a/toke.c
+++ b/toke.c
@@ -1083,7 +1083,7 @@ STATIC char *
 S_force_version(pTHX_ char *s, int guessing)
 {
     dVAR;
-    OP *version = Nullop;
+    OP *version = NULL;
     char *d;
 
     s = skipspace(s);
@@ -1206,7 +1206,7 @@ S_sublex_start(pTHX)
 
     if (op_type == OP_NULL) {
 	yylval.opval = PL_lex_op;
-	PL_lex_op = Nullop;
+	PL_lex_op = NULL;
 	return THING;
     }
     if (op_type == OP_CONST || op_type == OP_READLINE) {
@@ -1238,7 +1238,7 @@ S_sublex_start(pTHX)
     PL_expect = XTERM;
     if (PL_lex_op) {
 	yylval.opval = PL_lex_op;
-	PL_lex_op = Nullop;
+	PL_lex_op = NULL;
 	return PMFUNC;
     }
     else
@@ -1302,7 +1302,7 @@ S_sublex_push(pTHX)
     if (PL_lex_inwhat == OP_MATCH || PL_lex_inwhat == OP_QR || PL_lex_inwhat == OP_SUBST)
 	PL_lex_inpat = PL_sublex_info.sub_op;
     else
-	PL_lex_inpat = Nullop;
+	PL_lex_inpat = NULL;
 
     return '(';
 }
@@ -1893,15 +1893,15 @@ S_scan_const(pTHX_ char *start)
 	   and then encode the next character */
 	if ((has_utf8 || this_utf8) && !NATIVE_IS_INVARIANT((U8)(*s))) {
 	    STRLEN len  = 1;
-	    const UV uv       = (this_utf8) ? utf8n_to_uvchr((U8*)s, send - s, &len, 0) : (UV) ((U8) *s);
-	    const STRLEN need = UNISKIP(NATIVE_TO_UNI(uv));
+	    const UV nextuv   = (this_utf8) ? utf8n_to_uvchr((U8*)s, send - s, &len, 0) : (UV) ((U8) *s);
+	    const STRLEN need = UNISKIP(NATIVE_TO_UNI(nextuv));
 	    s += len;
 	    if (need > len) {
 		/* encoded value larger than old, need extra space (NOTE: SvCUR() not set here) */
 		const STRLEN off = d - SvPVX_const(sv);
 		d = SvGROW(sv, SvLEN(sv) + (need-len)) + off;
 	    }
-	    d = (char*)uvchr_to_utf8((U8*)d, uv);
+	    d = (char*)uvchr_to_utf8((U8*)d, nextuv);
 	    has_utf8 = TRUE;
 	}
 	else {
@@ -2399,7 +2399,7 @@ S_tokenize_use(pTHX_ int is_use, char *s) {
     if (isDIGIT(*s) || (*s == 'v' && isDIGIT(s[1]))) {
 	s = force_version(s, TRUE);
 	if (*s == ';' || (s = skipspace(s), *s == ';')) {
-	    PL_nextval[PL_nexttoke].opval = Nullop;
+	    PL_nextval[PL_nexttoke].opval = NULL;
 	    force_next(WORD);
 	}
 	else if (*s == 'v') {
@@ -3272,7 +3272,7 @@ Perl_yylex(pTHX)
 	    PL_expect = XTERMBLOCK;
 	 grabattrs:
 	    s = skipspace(s);
-	    attrs = Nullop;
+	    attrs = NULL;
 	    while (isIDFIRST_lazy_if(s,UTF)) {
 		I32 tmp;
 		d = scan_word(s, PL_tokenbuf, sizeof PL_tokenbuf, FALSE, &len);
@@ -3846,9 +3846,9 @@ Perl_yylex(pTHX)
 			    char tmpbuf[sizeof PL_tokenbuf];
 			    for (t++; isSPACE(*t); t++) ;
 			    if (isIDFIRST_lazy_if(t,UTF)) {
-				STRLEN len;
+				STRLEN dummylen;
 				t = scan_word(t, tmpbuf, sizeof tmpbuf, TRUE,
-					      &len);
+					      &dummylen);
 				for (; isSPACE(*t); t++) ;
 				if (*t == ';' && get_cv(tmpbuf, FALSE))
 				    Perl_warner(aTHX_ packWARN(WARN_SYNTAX),
@@ -4464,9 +4464,9 @@ Perl_yylex(pTHX)
 		    PL_last_lop_op = OP_ENTERSUB;
 		    /* Is there a prototype? */
 		    if (SvPOK(cv)) {
-			STRLEN len;
-			const char *proto = SvPV_const((SV*)cv, len);
-			if (!len)
+			STRLEN protolen;
+			const char *proto = SvPV_const((SV*)cv, protolen);
+			if (!protolen)
 			    TERM(FUNC0SUB);
 			if (*proto == '$' && proto[1] == '\0')
 			    OPERATOR(UNIOPSUB);
@@ -5104,10 +5104,10 @@ Perl_yylex(pTHX)
 		    /* [perl #16184] */
 		    && !(t[0] == '=' && t[1] == '>')
 		) {
-		    int len = (int)(d-s);
+		    int parms_len = (int)(d-s);
 		    Perl_warner(aTHX_ packWARN(WARN_PRECEDENCE),
 			   "Precedence problem: open %.*s should be open(%.*s)",
-			    len, s, len, s);
+			    parms_len, s, parms_len, s);
 		}
 	    }
 	    LOP(OP_OPEN,XTERM);
@@ -5172,7 +5172,7 @@ Perl_yylex(pTHX)
 	    PL_expect = XOPERATOR;
 	    force_next(')');
 	    if (SvCUR(PL_lex_stuff)) {
-		OP *words = Nullop;
+		OP *words = NULL;
 		int warned = 0;
 		d = SvPV_force(PL_lex_stuff, len);
 		while (len) {
@@ -10373,13 +10373,13 @@ S_scan_str(pTHX_ char *start, int keep_quoted, int keep_delims)
 
 	/* update debugger info */
 	if (PERLDB_LINE && PL_curstash != PL_debstash) {
-	    SV * const sv = newSV(0);
+	    SV * const line_sv = newSV(0);
 
-	    sv_upgrade(sv, SVt_PVMG);
-	    sv_setsv(sv,PL_linestr);
-            (void)SvIOK_on(sv);
-            SvIV_set(sv, 0);
-	    av_store(CopFILEAVx(PL_curcop), (I32)CopLINE(PL_curcop), sv);
+	    sv_upgrade(line_sv, SVt_PVMG);
+	    sv_setsv(line_sv,PL_linestr);
+	    (void)SvIOK_on(line_sv);
+	    SvIV_set(line_sv, 0);
+	    av_store(CopFILEAVx(PL_curcop), (I32)CopLINE(PL_curcop), line_sv);
 	}
 
 	/* having changed the buffer, we must update PL_bufend */
@@ -10815,7 +10815,7 @@ vstring:
     if (sv)
 	lvalp->opval = newSVOP(OP_CONST, 0, sv);
     else
-	lvalp->opval = Nullop;
+	lvalp->opval = NULL;
 
     return (char *)s;
 }
@@ -10922,6 +10922,8 @@ S_set_csh(pTHX)
     dVAR;
     if (!PL_cshlen)
 	PL_cshlen = strlen(PL_cshname);
+#else
+    PERL_UNUSED_ARG(my_perl);
 #endif
 }
 
diff --git a/utf8.c b/utf8.c
index e3d8d09662..a926735c9e 100644
--- a/utf8.c
+++ b/utf8.c
@@ -186,7 +186,7 @@ five bytes or more.
 
 =cut */
 STATIC STRLEN
-S_is_utf8_char_slow(pTHX_ const U8 *s, const STRLEN len)
+S_is_utf8_char_slow(const U8 *s, const STRLEN len)
 {
     U8 u = *s;
     STRLEN slen;
diff --git a/util.c b/util.c
index 420232c4db..c10dd29e11 100644
--- a/util.c
+++ b/util.c
@@ -1046,8 +1046,8 @@ Perl_mess(pTHX_ const char *pat, ...)
     return retval;
 }
 
-STATIC COP*
-S_closest_cop(pTHX_ COP *cop, const OP *o)
+STATIC const COP*
+S_closest_cop(pTHX_ const COP *cop, const OP *o)
 {
     dVAR;
     /* Look for PL_op starting from o.  cop is the last COP we've seen. */
@@ -1056,15 +1056,15 @@ S_closest_cop(pTHX_ COP *cop, const OP *o)
 	return cop;
 
     if (o->op_flags & OPf_KIDS) {
-	OP *kid;
+	const OP *kid;
 	for (kid = cUNOPo->op_first; kid; kid = kid->op_sibling) {
-	    COP *new_cop;
+	    const COP *new_cop;
 
 	    /* If the OP_NEXTSTATE has been optimised away we can still use it
 	     * the get the file and line number. */
 
 	    if (kid->op_type == OP_NULL && kid->op_targ == OP_NEXTSTATE)
-		cop = (COP *)kid;
+		cop = (const COP *)kid;
 
 	    /* Keep searching, and return when we've found something. */
 
@@ -1076,7 +1076,7 @@ S_closest_cop(pTHX_ COP *cop, const OP *o)
 
     /* Nothing found. */
 
-    return Null(COP *);
+    return NULL;
 }
 
 SV *
@@ -1084,11 +1084,9 @@ Perl_vmess(pTHX_ const char *pat, va_list *args)
 {
     dVAR;
     SV * const sv = mess_alloc();
-    static const char dgd[] = " during global destruction.\n";
 
-    sv_vsetpvfn(sv, pat, strlen(pat), args, Null(SV**), 0, Null(bool*));
+    sv_vsetpvfn(sv, pat, strlen(pat), args, NULL, 0, NULL);
     if (!SvCUR(sv) || *(SvEND(sv) - 1) != '\n') {
-
 	/*
 	 * Try and find the file and line for PL_op.  This will usually be
 	 * PL_curcop, but it might be a cop that has been optimised away.  We
@@ -1097,7 +1095,8 @@ Perl_vmess(pTHX_ const char *pat, va_list *args)
 	 */
 
 	const COP *cop = closest_cop(PL_curcop, PL_curcop->op_sibling);
-	if (!cop) cop = PL_curcop;
+	if (!cop)
+	    cop = PL_curcop;
 
 	if (CopLINE(cop))
 	    Perl_sv_catpvf(aTHX_ sv, " at %s line %"IVdf,
@@ -1106,12 +1105,13 @@ Perl_vmess(pTHX_ const char *pat, va_list *args)
 	    const bool line_mode = (RsSIMPLE(PL_rs) &&
 			      SvCUR(PL_rs) == 1 && *SvPVX_const(PL_rs) == '\n');
 	    Perl_sv_catpvf(aTHX_ sv, ", <%s> %s %"IVdf,
-			   PL_last_in_gv == PL_argvgv ?
-			   "" : GvNAME(PL_last_in_gv),
+			   PL_last_in_gv == PL_argvgv ? "" : GvNAME(PL_last_in_gv),
 			   line_mode ? "line" : "chunk",
 			   (IV)IoLINES(GvIOp(PL_last_in_gv)));
 	}
-	sv_catpv(sv, PL_dirty ? dgd : ".\n");
+	if (PL_dirty)
+	    sv_catpvs(sv, " during global destruction");
+	sv_catpvs(sv, ".\n");
     }
     return sv;
 }