Integrate:

[ 24965]
Subject: [PATCH] Pre-YAPC consting fun
Message-ID: <20050623190423.GA13835@petdance.com>
p4raw-link: @24965 on //depot/perl: 8772537cf6d022a54f738ccb84b65a7f21ccf1b2

p4raw-id: //depot/maint-5.8/perl@25555
p4raw-integrated: from //depot/perl@25554 'merge in' taint.c (@24800..)
p4raw-edited: from //depot/perl@24965 'edit in' locale.c (@24445..)
	embed.fnc proto.h (@24962..)
p4raw-integrated: from //depot/perl@24965 'edit in' mg.c (@24943..)
	util.c (@24945..) 'merge in' perlio.c (@24945..) pp_ctl.c
	scope.c (@24959..) embed.h (@24962..) pp_sys.c (@24963..)

11 files changed, 240 insertions, 192 deletions

diff --git a/embed.fnc b/embed.fnc
index d7e1bc5344..9dd15f8fc7 100644
--- a/embed.fnc
+++ b/embed.fnc
@@ -258,7 +258,7 @@ Ap	|char*	|vform		|const char* pat|va_list* args
 Ap	|void	|free_tmps
 p	|OP*	|gen_constant_list|OP* o
 #if !defined(HAS_GETENV_LEN)
-p	|char*	|getenv_len	|const char* key|unsigned long *len
+p	|char*	|getenv_len	|NN const char* key|NN unsigned long *len
 #endif
 Ap	|void	|gp_free	|GV* gv
 Ap	|GP*	|gp_ref		|GP* gp
@@ -405,7 +405,7 @@ p	|int	|magic_existspack|SV* sv|MAGIC* mg
 p	|int	|magic_freeregexp|SV* sv|MAGIC* mg
 p	|int	|magic_freeovrld|SV* sv|MAGIC* mg
 p	|int	|magic_get	|SV* sv|MAGIC* mg
-p	|int	|magic_getarylen|SV* sv|MAGIC* mg
+p	|int	|magic_getarylen|NN SV* sv|NN MAGIC* mg
 p	|int	|magic_getdefelem|SV* sv|MAGIC* mg
 p	|int	|magic_getglob	|SV* sv|MAGIC* mg
 p	|int	|magic_getnkeys	|SV* sv|MAGIC* mg
@@ -603,9 +603,9 @@ Apd	|HV*	|get_hv		|const char* name|I32 create
 Apd	|CV*	|get_cv		|const char* name|I32 create
 Ap	|int	|init_i18nl10n	|int printwarn
 Ap	|int	|init_i18nl14n	|int printwarn
-Ap	|void	|new_collate	|NN char* newcoll
+Ap	|void	|new_collate	|NULLOK char* newcoll
 Ap	|void	|new_ctype	|NN char* newctype
-Ap	|void	|new_numeric	|NN char* newcoll
+Ap	|void	|new_numeric	|NULLOK char* newcoll
 Ap	|void	|set_numeric_local
 Ap	|void	|set_numeric_radix
 Ap	|void	|set_numeric_standard
@@ -823,7 +823,7 @@ Ap	|SV*	|swash_init	|char* pkg|char* name|SV* listsv \
 				|I32 minbits|I32 none
 Ap	|UV	|swash_fetch	|SV *sv|U8 *ptr|bool do_utf8
 Ap	|void	|taint_env
-Ap	|void	|taint_proper	|const char* f|const char* s
+Ap	|void	|taint_proper	|NULLOK const char* f|NN const char* s
 Apd	|UV	|to_utf8_case	|NN U8 *p|NN U8* ustrp|STRLEN *lenp \
 				|SV **swash|char *normal|char *special
 Apd	|UV	|to_utf8_lower	|NN U8 *p|NN U8* ustrp|STRLEN *lenp
@@ -1031,6 +1031,9 @@ s	|void	|save_magic	|I32 mgs_ix|NN SV *sv
 s	|int	|magic_methpack	|NN SV *sv|NN const MAGIC *mg|NN const char *meth
 s	|int	|magic_methcall	|NN SV *sv|NN const MAGIC *mg|NN const char *meth|I32 f \
 				|int n|SV *val
+s	|void	|restore_magic	|NN const void *p
+s	|void	|unwind_handler_stack|NN const void *p
+
 #endif
 
 #if defined(PERL_IN_OP_C) || defined(PERL_DECL_PROT)
@@ -1321,11 +1324,11 @@ s	|SV*|isa_lookup	|HV *stash|const char *name|HV *name_stash|int len|int level
 #endif
 
 #if defined(PERL_IN_LOCALE_C) || defined(PERL_DECL_PROT)
-s	|char*	|stdize_locale	|char* locs
+s	|char*	|stdize_locale	|NN char* locs
 #endif
 
 #if defined(PERL_IN_UTIL_C) || defined(PERL_DECL_PROT)
-s	|COP*	|closest_cop	|COP *cop|OP *o
+s	|COP*	|closest_cop	|NN COP *cop|NULLOK const OP *o
 s	|SV*	|mess_alloc
 #endif
 
diff --git a/embed.h b/embed.h
index 91abc89cc4..8dcbbabd47 100644
--- a/embed.h
+++ b/embed.h
@@ -1080,6 +1080,8 @@
 #define save_magic		S_save_magic
 #define magic_methpack		S_magic_methpack
 #define magic_methcall		S_magic_methcall
+#define restore_magic		S_restore_magic
+#define unwind_handler_stack	S_unwind_handler_stack
 #endif
 #endif
 #if defined(PERL_IN_OP_C) || defined(PERL_DECL_PROT)
@@ -3107,6 +3109,8 @@
 #define save_magic(a,b)		S_save_magic(aTHX_ a,b)
 #define magic_methpack(a,b,c)	S_magic_methpack(aTHX_ a,b,c)
 #define magic_methcall(a,b,c,d,e,f)	S_magic_methcall(aTHX_ a,b,c,d,e,f)
+#define restore_magic(a)	S_restore_magic(aTHX_ a)
+#define unwind_handler_stack(a)	S_unwind_handler_stack(aTHX_ a)
 #endif
 #endif
 #if defined(PERL_IN_OP_C) || defined(PERL_DECL_PROT)
diff --git a/locale.c b/locale.c
index 3779279e57..2590fd7bc3 100644
--- a/locale.c
+++ b/locale.c
@@ -52,24 +52,19 @@
 STATIC char *
 S_stdize_locale(pTHX_ char *locs)
 {
-    char *s;
+    const char *s = strchr(locs, '=');
     bool okay = TRUE;
 
-    if ((s = strchr(locs, '='))) {
-	char *t;
-
+    if (s) {
+	const char * const t = strchr(s, '.');
 	okay = FALSE;
-	if ((t = strchr(s, '.'))) {
-	    char *u;
-
-	    if ((u = strchr(t, '\n'))) {
-
-		if (u[1] == 0) {
-		    STRLEN len = u - s;
-		    Move(s + 1, locs, len, char);
-		    locs[len] = 0;
-		    okay = TRUE;
-		}
+	if (t) {
+	    const char * const u = strchr(t, '\n');
+	    if (u && (u[1] == 0)) {
+		const STRLEN len = u - s;
+		Move(s + 1, locs, len, char);
+		locs[len] = 0;
+		okay = TRUE;
 	    }
 	}
     }
@@ -186,7 +181,7 @@ Perl_new_ctype(pTHX_ char *newctype)
     }
 
 #endif /* USE_LOCALE_CTYPE */
-    (void)newctype;
+    PERL_UNUSED_ARG(newctype);
 }
 
 /*
@@ -221,9 +216,9 @@ Perl_new_collate(pTHX_ char *newcoll)
 	  /* 50: surely no system expands a char more. */
 #define XFRMBUFSIZE  (2 * 50)
 	  char xbuf[XFRMBUFSIZE];
-	  Size_t fa = strxfrm(xbuf, "a",  XFRMBUFSIZE);
-	  Size_t fb = strxfrm(xbuf, "ab", XFRMBUFSIZE);
-	  SSize_t mult = fb - fa;
+	  const Size_t fa = strxfrm(xbuf, "a",  XFRMBUFSIZE);
+	  const Size_t fb = strxfrm(xbuf, "ab", XFRMBUFSIZE);
+	  const SSize_t mult = fb - fa;
 	  if (mult < 1)
 	      Perl_croak(aTHX_ "strxfrm() gets absurd");
 	  PL_collxfrm_base = (fa > (Size_t)mult) ? (fa - mult) : 0;
diff --git a/mg.c b/mg.c
index 6bb879687d..2fd8afe92c 100644
--- a/mg.c
+++ b/mg.c
@@ -63,9 +63,6 @@ Signal_t Perl_csighandler(int sig);
 #  define  FAKE_DEFAULT_SIGNAL_HANDLERS
 #endif
 
-static void restore_magic(pTHX_ const void *p);
-static void unwind_handler_stack(pTHX_ const void *p);
-
 #ifdef __Lynx__
 /* Missing protos on LynxOS */
 void setruid(uid_t id);
@@ -91,7 +88,7 @@ S_save_magic(pTHX_ I32 mgs_ix, SV *sv)
     MGS* mgs;
     assert(SvMAGICAL(sv));
 
-    SAVEDESTRUCTOR_X(restore_magic, INT2PTR(void*, (IV)mgs_ix));
+    SAVEDESTRUCTOR_X(S_restore_magic, INT2PTR(void*, (IV)mgs_ix));
 
     mgs = SSPTR(mgs_ix, MGS*);
     mgs->mgs_sv = sv;
@@ -198,7 +195,7 @@ Perl_mg_get(pTHX_ SV *sv)
 	}
     }
 
-    restore_magic(aTHX_ INT2PTR(void *, (IV)mgs_ix));
+    restore_magic(INT2PTR(void *, (IV)mgs_ix));
 
     if (SvREFCNT(sv) == 1) {
 	/* We hold the last reference to this SV, which implies that the
@@ -236,7 +233,7 @@ Perl_mg_set(pTHX_ SV *sv)
 	    CALL_FPTR(vtbl->svt_set)(aTHX_ sv, mg);
     }
 
-    restore_magic(aTHX_ INT2PTR(void*, (IV)mgs_ix));
+    restore_magic(INT2PTR(void*, (IV)mgs_ix));
     return 0;
 }
 
@@ -261,7 +258,7 @@ Perl_mg_length(pTHX_ SV *sv)
 	    save_magic(mgs_ix, sv);
 	    /* omit MGf_GSKIP -- not changed here */
 	    len = CALL_FPTR(vtbl->svt_len)(aTHX_ sv, mg);
-	    restore_magic(aTHX_ INT2PTR(void*, (IV)mgs_ix));
+	    restore_magic(INT2PTR(void*, (IV)mgs_ix));
 	    return len;
 	}
     }
@@ -288,7 +285,7 @@ Perl_mg_size(pTHX_ SV *sv)
 	    save_magic(mgs_ix, sv);
 	    /* omit MGf_GSKIP -- not changed here */
 	    len = CALL_FPTR(vtbl->svt_len)(aTHX_ sv, mg);
-	    restore_magic(aTHX_ INT2PTR(void*, (IV)mgs_ix));
+	    restore_magic(INT2PTR(void*, (IV)mgs_ix));
 	    return len;
 	}
     }
@@ -329,7 +326,7 @@ Perl_mg_clear(pTHX_ SV *sv)
 	    CALL_FPTR(vtbl->svt_clear)(aTHX_ sv, mg);
     }
 
-    restore_magic(aTHX_ INT2PTR(void*, (IV)mgs_ix));
+    restore_magic(INT2PTR(void*, (IV)mgs_ix));
     return 0;
 }
 
@@ -422,7 +419,7 @@ U32
 Perl_magic_regdata_cnt(pTHX_ SV *sv, MAGIC *mg)
 {
     register const REGEXP *rx;
-    (void)sv;
+    PERL_UNUSED_ARG(sv);
 
     if (PL_curpm && (rx = PM_GETRE(PL_curpm))) {
 	if (mg->mg_obj)		/* @+ */
@@ -456,7 +453,7 @@ Perl_magic_regdatum_get(pTHX_ SV *sv, MAGIC *mg)
 		    i = s;
 
 		if (i > 0 && RX_MATCH_UTF8(rx)) {
-		    char *b = rx->subbeg;
+		    const char * const b = rx->subbeg;
 		    if (b)
 		        i = Perl_utf8_length(aTHX_ (U8*)b, (U8*)(b+i));
 		}
@@ -470,7 +467,7 @@ Perl_magic_regdatum_get(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_regdatum_set(pTHX_ SV *sv, MAGIC *mg)
 {
-    (void)sv; (void)mg;
+    PERL_UNUSED_ARG(sv); PERL_UNUSED_ARG(mg);
     Perl_croak(aTHX_ PL_no_modify);
     NORETURN_FUNCTION_END;
 }
@@ -640,7 +637,7 @@ Perl_magic_get(pTHX_ SV *sv, MAGIC *mg)
 	     }
 #else
 	     {
-		 int saveerrno = errno;
+		 const int saveerrno = errno;
 		 sv_setnv(sv, (NV)errno);
 		 sv_setpv(sv, errno ? Strerror(errno) : "");
 		 errno = saveerrno;
@@ -889,7 +886,7 @@ Perl_magic_get(pTHX_ SV *sv, MAGIC *mg)
 	sv_setpv(sv, errno ? Strerror(errno) : "");
 #else
 	{
-	int saveerrno = errno;
+	const int saveerrno = errno;
 	sv_setnv(sv, (NV)errno);
 #ifdef OS2
 	if (errno == errno_isOS2 || errno == errno_isOS2_set)
@@ -948,7 +945,7 @@ Perl_magic_get(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_getuvar(pTHX_ SV *sv, MAGIC *mg)
 {
-    struct ufuncs *uf = (struct ufuncs *)mg->mg_ptr;
+    struct ufuncs * const uf = (struct ufuncs *)mg->mg_ptr;
 
     if (uf && uf->uf_val)
 	(*uf->uf_val)(aTHX_ uf->uf_index, sv);
@@ -1008,7 +1005,7 @@ Perl_magic_setenv(pTHX_ SV *sv, MAGIC *mg)
 	}
 #endif /* VMS */
 	if (s && klen == 4 && strEQ(ptr,"PATH")) {
-	    const char *strend = s + len;
+	    const char * const strend = s + len;
 
 	    while (s < strend) {
 		char tmpbuf[256];
@@ -1034,7 +1031,7 @@ Perl_magic_setenv(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_clearenv(pTHX_ SV *sv, MAGIC *mg)
 {
-    (void)sv;
+    PERL_UNUSED_ARG(sv);
     my_setenv(MgPV_nolen_const(mg),Nullch);
     return 0;
 }
@@ -1093,8 +1090,8 @@ Perl_magic_clear_all_env(pTHX_ SV *sv, MAGIC *mg)
 #   endif /* PERL_IMPLICIT_SYS || WIN32 */
 #endif /* VMS || EPOC */
 #endif /* !PERL_MICRO */
-    (void)sv;
-    (void)mg;
+    PERL_UNUSED_ARG(sv);
+    PERL_UNUSED_ARG(mg);
     return 0;
 }
 
@@ -1120,9 +1117,8 @@ restore_sigmask(pTHX_ SV *save_sv)
 int
 Perl_magic_getsig(pTHX_ SV *sv, MAGIC *mg)
 {
-    I32 i;
     /* Are we fetching a signal entry? */
-    i = whichsig(MgPV_nolen_const(mg));
+    const I32 i = whichsig(MgPV_nolen_const(mg));
     if (i > 0) {
     	if(PL_psig_ptr[i])
     	    sv_setsv(sv,PL_psig_ptr[i]);
@@ -1152,8 +1148,8 @@ Perl_magic_clearsig(pTHX_ SV *sv, MAGIC *mg)
     /* XXX Some of this code was copied from Perl_magic_setsig. A little
      * refactoring might be in order.
      */
-    register const char *s = MgPV_nolen_const(mg);
-    (void)sv;
+    register const char * const s = MgPV_nolen_const(mg);
+    PERL_UNUSED_ARG(sv);
     if (*s == '_') {
 	SV** svp;
 	if (strEQ(s,"__DIE__"))
@@ -1163,15 +1159,14 @@ Perl_magic_clearsig(pTHX_ SV *sv, MAGIC *mg)
 	else
 	    Perl_croak(aTHX_ "No such hook: %s", s);
 	if (*svp) {
-            SV *to_dec = *svp;
+            SV * const to_dec = *svp;
 	    *svp = 0;
     	    SvREFCNT_dec(to_dec);
 	}
     }
     else {
-	I32 i;
 	/* Are we clearing a signal entry? */
-	i = whichsig(s);
+	const I32 i = whichsig(s);
 	if (i > 0) {
 #ifdef HAS_SIGPROCMASK
 	    sigset_t set, save;
@@ -1411,8 +1406,8 @@ Perl_magic_setsig(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_setisa(pTHX_ SV *sv, MAGIC *mg)
 {
-    (void)sv;
-    (void)mg;
+    PERL_UNUSED_ARG(sv);
+    PERL_UNUSED_ARG(mg);
     PL_sub_generation++;
     return 0;
 }
@@ -1420,8 +1415,8 @@ Perl_magic_setisa(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_setamagic(pTHX_ SV *sv, MAGIC *mg)
 {
-    (void)sv;
-    (void)mg;
+    PERL_UNUSED_ARG(sv);
+    PERL_UNUSED_ARG(mg);
     /* HV_badAMAGIC_on(Sv_STASH(sv)); */
     PL_amagic_generation++;
 
@@ -1433,7 +1428,7 @@ Perl_magic_getnkeys(pTHX_ SV *sv, MAGIC *mg)
 {
     HV * const hv = (HV*)LvTARG(sv);
     I32 i = 0;
-    (void)mg;
+    PERL_UNUSED_ARG(mg);
 
     if (hv) {
          (void) hv_iterinit(hv);
@@ -1452,7 +1447,7 @@ Perl_magic_getnkeys(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_setnkeys(pTHX_ SV *sv, MAGIC *mg)
 {
-    (void)mg;
+    PERL_UNUSED_ARG(mg);
     if (LvTARG(sv)) {
 	hv_ksplit((HV*)LvTARG(sv), SvIV(sv));
     }
@@ -1606,8 +1601,8 @@ Perl_magic_scalarpack(pTHX_ HV *hv, MAGIC *mg)
 {
     dSP;
     SV *retval = &PL_sv_undef;
-    SV *tied = SvTIED_obj((SV*)hv, mg);
-    HV *pkg = SvSTASH((SV*)SvRV(tied));
+    SV * const tied = SvTIED_obj((SV*)hv, mg);
+    HV * const pkg = SvSTASH((SV*)SvRV(tied));
    
     if (!gv_fetchmethod_autoload(pkg, "SCALAR", FALSE)) {
         SV *key;
@@ -1639,21 +1634,19 @@ Perl_magic_scalarpack(pTHX_ HV *hv, MAGIC *mg)
 int
 Perl_magic_setdbline(pTHX_ SV *sv, MAGIC *mg)
 {
-    OP *o;
-    I32 i;
-    GV* gv;
-    SV** svp;
-
-    gv = PL_DBline;
-    i = SvTRUE(sv);
-    svp = av_fetch(GvAV(gv),
+    GV * const gv = PL_DBline;
+    const I32 i = SvTRUE(sv);
+    SV ** const svp = av_fetch(GvAV(gv),
 		     atoi(MgPV_nolen_const(mg)), FALSE);
-    if (svp && SvIOKp(*svp) && (o = INT2PTR(OP*,SvIVX(*svp)))) {
-	/* set or clear breakpoint in the relevant control op */
-	if (i)
-	    o->op_flags |= OPf_SPECIAL;
-	else
-	    o->op_flags &= ~OPf_SPECIAL;
+    if (svp && SvIOKp(*svp)) {
+	OP * const o = INT2PTR(OP*,SvIVX(*svp));
+	if (o) {
+	    /* set or clear breakpoint in the relevant control op */
+	    if (i)
+		o->op_flags |= OPf_SPECIAL;
+	    else
+		o->op_flags &= ~OPf_SPECIAL;
+	}
     }
     return 0;
 }
@@ -1675,7 +1668,7 @@ Perl_magic_setarylen(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_getpos(pTHX_ SV *sv, MAGIC *mg)
 {
-    SV* lsv = LvTARG(sv);
+    SV* const lsv = LvTARG(sv);
 
     if (SvTYPE(lsv) >= SVt_PVMG && SvMAGIC(lsv)) {
 	mg = mg_find(lsv, PERL_MAGIC_regex_global);
@@ -1694,7 +1687,7 @@ Perl_magic_getpos(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_setpos(pTHX_ SV *sv, MAGIC *mg)
 {
-    SV* lsv = LvTARG(sv);
+    SV* const lsv = LvTARG(sv);
     SSize_t pos;
     STRLEN len;
     STRLEN ulen = 0;
@@ -1746,7 +1739,7 @@ Perl_magic_setpos(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_getglob(pTHX_ SV *sv, MAGIC *mg)
 {
-    (void)mg;
+    PERL_UNUSED_ARG(mg);
     if (SvFAKE(sv)) {			/* FAKE globs can get coerced */
 	SvFAKE_off(sv);
 	gv_efullname3(sv,((GV*)sv), "*");
@@ -1763,7 +1756,7 @@ Perl_magic_setglob(pTHX_ SV *sv, MAGIC *mg)
     register char *s;
     GV* gv;
     STRLEN n_a;
-    (void)mg;
+    PERL_UNUSED_ARG(mg);
 
     if (!SvOK(sv))
 	return 0;
@@ -1787,7 +1780,7 @@ Perl_magic_getsubstr(pTHX_ SV *sv, MAGIC *mg)
     const char * const tmps = SvPV_const(lsv,len);
     I32 offs = LvTARGOFF(sv);
     I32 rem = LvTARGLEN(sv);
-    (void)mg;
+    PERL_UNUSED_ARG(mg);
 
     if (SvUTF8(lsv))
 	sv_pos_u2b(lsv, &offs, &rem);
@@ -1809,7 +1802,7 @@ Perl_magic_setsubstr(pTHX_ SV *sv, MAGIC *mg)
     SV * const lsv = LvTARG(sv);
     I32 lvoff = LvTARGOFF(sv);
     I32 lvlen = LvTARGLEN(sv);
-    (void)mg;
+    PERL_UNUSED_ARG(mg);
 
     if (DO_UTF8(sv)) {
 	sv_utf8_upgrade(lsv);
@@ -1832,6 +1825,7 @@ Perl_magic_setsubstr(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_gettaint(pTHX_ SV *sv, MAGIC *mg)
 {
+    PERL_UNUSED_ARG(sv);
     TAINT_IF((mg->mg_len & 1) ||
 	     ((mg->mg_len & 2) && mg->mg_obj == sv));	/* kludge */
     return 0;
@@ -1840,7 +1834,7 @@ Perl_magic_gettaint(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_settaint(pTHX_ SV *sv, MAGIC *mg)
 {
-    (void)sv;
+    PERL_UNUSED_ARG(sv);
     if (PL_localizing) {
 	if (PL_localizing == 1)
 	    mg->mg_len <<= 1;
@@ -1858,7 +1852,7 @@ int
 Perl_magic_getvec(pTHX_ SV *sv, MAGIC *mg)
 {
     SV * const lsv = LvTARG(sv);
-    (void)mg;
+    PERL_UNUSED_ARG(mg);
 
     if (!lsv) {
 	SvOK_off(sv);
@@ -1872,7 +1866,7 @@ Perl_magic_getvec(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_setvec(pTHX_ SV *sv, MAGIC *mg)
 {
-    (void)mg;
+    PERL_UNUSED_ARG(mg);
     do_vecset(sv);	/* XXX slurp this routine */
     return 0;
 }
@@ -1883,9 +1877,9 @@ Perl_magic_getdefelem(pTHX_ SV *sv, MAGIC *mg)
     SV *targ = Nullsv;
     if (LvTARGLEN(sv)) {
 	if (mg->mg_obj) {
-	    SV *ahv = LvTARG(sv);
+	    SV * const ahv = LvTARG(sv);
 	    if (SvTYPE(ahv) == SVt_PVHV) {
-		HE *he = hv_fetch_ent((HV*)ahv, mg->mg_obj, FALSE, 0);
+		HE * const he = hv_fetch_ent((HV*)ahv, mg->mg_obj, FALSE, 0);
 		if (he)
 		    targ = HeVAL(he);
 	    }
@@ -1896,7 +1890,7 @@ Perl_magic_getdefelem(pTHX_ SV *sv, MAGIC *mg)
 	    }
 	}
 	else {
-	    AV* av = (AV*)LvTARG(sv);
+	    AV* const av = (AV*)LvTARG(sv);
 	    if ((I32)LvTARGOFF(sv) <= AvFILL(av))
 		targ = AvARRAY(av)[LvTARGOFF(sv)];
 	}
@@ -1919,7 +1913,7 @@ Perl_magic_getdefelem(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_setdefelem(pTHX_ SV *sv, MAGIC *mg)
 {
-    (void)mg;
+    PERL_UNUSED_ARG(mg);
     if (LvTARGLEN(sv))
 	vivify_defelem(sv);
     if (LvTARG(sv)) {
@@ -1938,9 +1932,9 @@ Perl_vivify_defelem(pTHX_ SV *sv)
     if (!LvTARGLEN(sv) || !(mg = mg_find(sv, PERL_MAGIC_defelem)))
 	return;
     if (mg->mg_obj) {
-	SV *ahv = LvTARG(sv);
+	SV * const ahv = LvTARG(sv);
 	if (SvTYPE(ahv) == SVt_PVHV) {
-	    HE *he = hv_fetch_ent((HV*)ahv, mg->mg_obj, TRUE, 0);
+	    HE * const he = hv_fetch_ent((HV*)ahv, mg->mg_obj, TRUE, 0);
 	    if (he)
 		value = HeVAL(he);
 	}
@@ -1953,7 +1947,7 @@ Perl_vivify_defelem(pTHX_ SV *sv)
 	    Perl_croak(aTHX_ PL_no_helem_sv, mg->mg_obj);
     }
     else {
-	AV* av = (AV*)LvTARG(sv);
+	AV* const av = (AV*)LvTARG(sv);
 	if ((I32)LvTARGLEN(sv) < 0 && (I32)LvTARGOFF(sv) > AvFILL(av))
 	    LvTARG(sv) = Nullsv;	/* array can't be extended */
 	else {
@@ -1974,10 +1968,10 @@ Perl_vivify_defelem(pTHX_ SV *sv)
 int
 Perl_magic_killbackrefs(pTHX_ SV *sv, MAGIC *mg)
 {
-    AV *av = (AV*)mg->mg_obj;
-    SV **svp = AvARRAY(av);
+    AV * const av = (AV*)mg->mg_obj;
+    SV ** const svp = AvARRAY(av);
     I32 i = AvFILLp(av);
-    (void)sv;
+    PERL_UNUSED_ARG(sv);
 
     while (i >= 0) {
 	if (svp[i]) {
@@ -2006,7 +2000,7 @@ Perl_magic_setmglob(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_setbm(pTHX_ SV *sv, MAGIC *mg)
 {
-    (void)mg;
+    PERL_UNUSED_ARG(mg);
     sv_unmagic(sv, PERL_MAGIC_bm);
     SvVALID_off(sv);
     return 0;
@@ -2015,7 +2009,7 @@ Perl_magic_setbm(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_setfm(pTHX_ SV *sv, MAGIC *mg)
 {
-    (void)mg;
+    PERL_UNUSED_ARG(mg);
     sv_unmagic(sv, PERL_MAGIC_fm);
     SvCOMPILED_off(sv);
     return 0;
@@ -2034,7 +2028,7 @@ Perl_magic_setuvar(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_setregexp(pTHX_ SV *sv, MAGIC *mg)
 {
-    (void)mg;
+    PERL_UNUSED_ARG(mg);
     sv_unmagic(sv, PERL_MAGIC_qr);
     return 0;
 }
@@ -2042,9 +2036,10 @@ Perl_magic_setregexp(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_freeregexp(pTHX_ SV *sv, MAGIC *mg)
 {
-    regexp *re = (regexp *)mg->mg_obj;
+    regexp * const re = (regexp *)mg->mg_obj;
+    PERL_UNUSED_ARG(sv);
+
     ReREFCNT_dec(re);
-    (void)sv;
     return 0;
 }
 
@@ -2056,7 +2051,7 @@ Perl_magic_setcollxfrm(pTHX_ SV *sv, MAGIC *mg)
      * RenE<eacute> Descartes said "I think not."
      * and vanished with a faint plop.
      */
-    (void)sv;
+    PERL_UNUSED_ARG(sv);
     if (mg->mg_ptr) {
 	Safefree(mg->mg_ptr);
 	mg->mg_ptr = NULL;
@@ -2070,7 +2065,7 @@ Perl_magic_setcollxfrm(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_setutf8(pTHX_ SV *sv, MAGIC *mg)
 {
-    (void)sv;
+    PERL_UNUSED_ARG(sv);
      Safefree(mg->mg_ptr);	/* The mg_ptr holds the pos cache. */
      mg->mg_ptr = 0;
      mg->mg_len = -1; 		/* The mg_len holds the len cache. */
@@ -2250,7 +2245,7 @@ Perl_magic_set(pTHX_ SV *sv, MAGIC *mg)
 	break;
     case '|':
 	{
-	    IO *io = GvIOp(PL_defoutgv);
+	    IO * const io = GvIOp(PL_defoutgv);
 	    if(!io)
 	      break;
 	    if ((SvIOK(sv) ? SvIVX(sv) : sv_2iv(sv)) == 0)
@@ -2581,12 +2576,12 @@ Perl_sighandler(int sig)
 #endif
     dSP;
     GV *gv = Nullgv;
-    HV *st;
-    SV *sv = Nullsv, *tSv = PL_Sv;
+    SV *sv = Nullsv;
+    SV * const tSv = PL_Sv;
     CV *cv = Nullcv;
     OP *myop = PL_op;
     U32 flags = 0;
-    XPV *tXpv = PL_Xpv;
+    XPV * const tXpv = PL_Xpv;
 
     if (PL_savestack_ix + 15 <= PL_savestack_max)
 	flags |= 1;
@@ -2607,7 +2602,7 @@ Perl_sighandler(int sig)
        infinity, so we fix 4 (in fact 5): */
     if (flags & 1) {
 	PL_savestack_ix += 5;		/* Protect save in progress. */
-	SAVEDESTRUCTOR_X(unwind_handler_stack, (void*)&flags);
+	SAVEDESTRUCTOR_X(S_unwind_handler_stack, (void*)&flags);
     }
     if (flags & 4)
 	PL_markstack_ptr++;		/* Protect mark. */
@@ -2619,8 +2614,10 @@ Perl_sighandler(int sig)
 	PL_scopestack_ix += 1;
     /* sv_2cv is too complicated, try a simpler variant first: */
     if (!SvROK(PL_psig_ptr[sig]) || !(cv = (CV*)SvRV(PL_psig_ptr[sig]))
-	|| SvTYPE(cv) != SVt_PVCV)
+	|| SvTYPE(cv) != SVt_PVCV) {
+	HV *st;
 	cv = sv_2cv(PL_psig_ptr[sig],&st,&gv,TRUE);
+    }
 
     if (!cv || !CvROOT(cv)) {
 	if (ckWARN(WARN_SIGNAL))
@@ -2690,10 +2687,10 @@ cleanup:
 
 
 static void
-restore_magic(pTHX_ const void *p)
+S_restore_magic(pTHX_ const void *p)
 {
-    MGS* mgs = SSPTR(PTR2IV(p), MGS*);
-    SV* sv = mgs->mgs_sv;
+    MGS* const mgs = SSPTR(PTR2IV(p), MGS*);
+    SV* const sv = mgs->mgs_sv;
 
     if (!sv)
         return;
@@ -2731,7 +2728,7 @@ restore_magic(pTHX_ const void *p)
 }
 
 static void
-unwind_handler_stack(pTHX_ const void *p)
+S_unwind_handler_stack(pTHX_ const void *p)
 {
     const U32 flags = *(const U32*)p;
 
diff --git a/perlio.c b/perlio.c
index a57ff9efd5..9bb3c9ef0d 100644
--- a/perlio.c
+++ b/perlio.c
@@ -163,9 +163,9 @@ perlsio_binmode(FILE *fp, int iotype, int mode)
     else
 	return 0;
 #  else
-    (void)fp;
-    (void)iotype;
-    (void)mode;
+    PERL_UNUSED_ARG(fp);
+    PERL_UNUSED_ARG(iotype);
+    PERL_UNUSED_ARG(mode);
     return 1;
 #  endif
 #endif
@@ -248,9 +248,9 @@ int
 PerlIO_binmode(pTHX_ PerlIO *fp, int iotype, int mode, const char *names)
 {
 #ifdef USE_SFIO
-    (void)iotype;
-    (void)mode;
-    (void)names;
+    PERL_UNUSED_ARG(iotype);
+    PERL_UNUSED_ARG(mode);
+    PERL_UNUSED_ARG(names);
     return 1;
 #else
     return perlsio_binmode(fp, iotype, mode);
@@ -1039,9 +1039,9 @@ PerlIO_layer_fetch(pTHX_ PerlIO_list_t *av, IV n, PerlIO_funcs *def)
 IV
 PerlIOPop_pushed(pTHX_ PerlIO *f, const char *mode, SV *arg, PerlIO_funcs *tab)
 {
-    (void)mode;
-    (void)arg;
-    (void)tab;
+    PERL_UNUSED_ARG(mode);
+    PERL_UNUSED_ARG(arg);
+    PERL_UNUSED_ARG(tab);
     if (PerlIOValid(f)) {
 	PerlIO_flush(f);
 	PerlIO_pop(aTHX_ f);
@@ -1216,9 +1216,9 @@ PerlIOBase_binmode(pTHX_ PerlIO *f)
 IV
 PerlIORaw_pushed(pTHX_ PerlIO *f, const char *mode, SV *arg, PerlIO_funcs *tab)
 {
-    (void)mode;
-    (void)arg;
-    (void)tab;
+    PERL_UNUSED_ARG(mode);
+    PERL_UNUSED_ARG(arg);
+    PERL_UNUSED_ARG(tab);
 
     if (PerlIOValid(f)) {
 	PerlIO *t;
@@ -1260,7 +1260,7 @@ PerlIO_apply_layera(pTHX_ PerlIO *f, const char *mode,
 {
     int code = 0;
     while (n < max) {
-	PerlIO_funcs *tab = PerlIO_layer_fetch(aTHX_ layers, n, NULL);
+	PerlIO_funcs * const tab = PerlIO_layer_fetch(aTHX_ layers, n, NULL);
 	if (tab) {
 	    if (!PerlIO_push(aTHX_ f, tab, mode, PerlIOArg)) {
 		code = -1;
@@ -1277,7 +1277,7 @@ PerlIO_apply_layers(pTHX_ PerlIO *f, const char *mode, const char *names)
 {
     int code = 0;
     if (f && names) {
-	PerlIO_list_t *layers = PerlIO_list_alloc(aTHX);
+	PerlIO_list_t * const layers = PerlIO_list_alloc(aTHX);
 	code = PerlIO_parse_layers(aTHX_ layers, names);
 	if (code == 0) {
 	    code = PerlIO_apply_layera(aTHX_ f, mode, layers, 0, layers->cur);
@@ -1815,8 +1815,8 @@ Perl_PerlIO_set_ptrcnt(pTHX_ PerlIO *f, STDCHAR * ptr, int cnt)
 IV
 PerlIOUtf8_pushed(pTHX_ PerlIO *f, const char *mode, SV *arg, PerlIO_funcs *tab)
 {
-    (void)mode;
-    (void)arg;
+    PERL_UNUSED_ARG(mode);
+    PERL_UNUSED_ARG(arg);
     if (PerlIOValid(f)) {
 	if (tab->kind & PERLIO_K_UTF8)
 	    PerlIOBase(f)->flags |= PERLIO_F_UTF8;
@@ -1894,8 +1894,8 @@ PerlIORaw_open(pTHX_ PerlIO_funcs *self, PerlIO_list_t *layers,
 	       IV n, const char *mode, int fd, int imode, int perm,
 	       PerlIO *old, int narg, SV **args)
 {
-    PerlIO_funcs *tab = PerlIO_default_btm();
-    (void)self;
+    PerlIO_funcs * const tab = PerlIO_default_btm();
+    PERL_UNUSED_ARG(self);
     if (tab && tab->Open)
 	 return (*tab->Open) (aTHX_ tab, layers, n - 1, mode, fd, imode, perm,
 			      old, narg, args);
@@ -1982,7 +1982,7 @@ IV
 PerlIOBase_pushed(pTHX_ PerlIO *f, const char *mode, SV *arg, PerlIO_funcs *tab)
 {
     PerlIOl * const l = PerlIOBase(f);
-    (void)arg;
+    PERL_UNUSED_ARG(arg);
 
     l->flags &= ~(PERLIO_F_CANREAD | PERLIO_F_CANWRITE |
 		  PERLIO_F_TRUNCATE | PERLIO_F_APPEND);
@@ -2040,7 +2040,7 @@ PerlIOBase_pushed(pTHX_ PerlIO *f, const char *mode, SV *arg, PerlIO_funcs *tab)
 IV
 PerlIOBase_popped(pTHX_ PerlIO *f)
 {
-    (void)f;
+    PERL_UNUSED_ARG(f);
     return 0;
 }
 
@@ -2091,14 +2091,14 @@ PerlIOBase_read(pTHX_ PerlIO *f, void *vbuf, Size_t count)
 IV
 PerlIOBase_noop_ok(pTHX_ PerlIO *f)
 {
-    (void)f;
+    PERL_UNUSED_ARG(f);
     return 0;
 }
 
 IV
 PerlIOBase_noop_fail(pTHX_ PerlIO *f)
 {
-    (void)f;
+    PERL_UNUSED_ARG(f);
     return -1;
 }
 
@@ -2949,7 +2949,7 @@ PerlIOStdio_invalidate_fileno(pTHX_ FILE *f)
      */
 #    error "Don't know how to set FILE.fileno on your platform"
 #endif
-    (void)f;
+    PERL_UNUSED_ARG(f);
     return 0;
 #  endif
 }
@@ -4770,8 +4770,8 @@ PerlIO_getname(PerlIO *f, char *buf)
     }
     return name;
 #else
-    (void)f;
-    (void)buf;
+    PERL_UNUSED_ARG(f);
+    PERL_UNUSED_ARG(buf);
     Perl_croak(aTHX_ "Don't know how to get file name");
     return Nullch;
 #endif
diff --git a/pp_ctl.c b/pp_ctl.c
index dfe2caa744..9b6bd7ee4b 100644
--- a/pp_ctl.c
+++ b/pp_ctl.c
@@ -1939,12 +1939,13 @@ PP(pp_last)
     register PERL_CONTEXT *cx;
     I32 pop2 = 0;
     I32 gimme;
-    I32 optype = 0;
+    I32 optype;
     OP *nextop;
     SV **newsp;
     PMOP *newpm;
     SV **mark;
     SV *sv = Nullsv;
+    PERL_UNUSED_VAR(optype);
 
     if (PL_op->op_flags & OPf_SPECIAL) {
 	cxix = dopoptoloop(cxstack_ix);
diff --git a/pp_sys.c b/pp_sys.c
index a3ce987d87..e08ea0b543 100644
--- a/pp_sys.c
+++ b/pp_sys.c
@@ -1307,8 +1307,8 @@ PP(pp_leavewrite)
     register IO * const io = GvIOp(gv);
     PerlIO * const ofp = IoOFP(io);
     PerlIO *fp;
-    SV **newsp = Null(SV**);
-    I32 gimme = 0;
+    SV **newsp;
+    I32 gimme;
     register PERL_CONTEXT *cx;
     PERL_UNUSED_VAR(newsp);
     PERL_UNUSED_VAR(gimme);
diff --git a/proto.h b/proto.h
index e1dbfa361b..c68cf68a58 100644
--- a/proto.h
+++ b/proto.h
@@ -87,9 +87,7 @@ PERL_CALLCONV HE*	Perl_avhv_iternext(pTHX_ AV *ar);
 PERL_CALLCONV SV*	Perl_avhv_iterval(pTHX_ AV *ar, HE* entry);
 PERL_CALLCONV HV*	Perl_avhv_keys(pTHX_ AV *ar);
 PERL_CALLCONV void	Perl_av_clear(pTHX_ AV* ar);
-PERL_CALLCONV SV*	Perl_av_delete(pTHX_ AV* ar, I32 key, I32 flags)
-			__attribute__warn_unused_result__;
-
+PERL_CALLCONV SV*	Perl_av_delete(pTHX_ AV* ar, I32 key, I32 flags);
 PERL_CALLCONV bool	Perl_av_exists(pTHX_ AV* ar, I32 key)
 			__attribute__warn_unused_result__;
 
@@ -111,9 +109,7 @@ PERL_CALLCONV AV*	Perl_av_make(pTHX_ I32 size, SV** svp)
 			__attribute__warn_unused_result__
 			__attribute__nonnull__(pTHX_2);
 
-PERL_CALLCONV SV*	Perl_av_pop(pTHX_ AV* ar)
-			__attribute__warn_unused_result__;
-
+PERL_CALLCONV SV*	Perl_av_pop(pTHX_ AV* ar);
 PERL_CALLCONV void	Perl_av_push(pTHX_ AV* ar, SV* val);
 PERL_CALLCONV void	Perl_av_reify(pTHX_ AV* ar);
 PERL_CALLCONV SV*	Perl_av_shift(pTHX_ AV* ar)
@@ -381,7 +377,10 @@ PERL_CALLCONV char*	Perl_vform(pTHX_ const char* pat, va_list* args);
 PERL_CALLCONV void	Perl_free_tmps(pTHX);
 PERL_CALLCONV OP*	Perl_gen_constant_list(pTHX_ OP* o);
 #if !defined(HAS_GETENV_LEN)
-PERL_CALLCONV char*	Perl_getenv_len(pTHX_ const char* key, unsigned long *len);
+PERL_CALLCONV char*	Perl_getenv_len(pTHX_ const char* key, unsigned long *len)
+			__attribute__nonnull__(pTHX_1)
+			__attribute__nonnull__(pTHX_2);
+
 #endif
 PERL_CALLCONV void	Perl_gp_free(pTHX_ GV* gv);
 PERL_CALLCONV GP*	Perl_gp_ref(pTHX_ GP* gp);
@@ -415,7 +414,6 @@ PERL_CALLCONV void	Perl_gv_fullname(pTHX_ SV* sv, GV* gv);
 PERL_CALLCONV void	Perl_gv_fullname4(pTHX_ SV* sv, GV* gv, const char* prefix, bool keepmain);
 PERL_CALLCONV void	Perl_gv_init(pTHX_ GV* gv, HV* stash, const char* name, STRLEN len, int multi)
 			__attribute__nonnull__(pTHX_1)
-			__attribute__nonnull__(pTHX_2)
 			__attribute__nonnull__(pTHX_3);
 
 PERL_CALLCONV HV*	Perl_gv_stashpv(pTHX_ const char* name, I32 create);
@@ -779,7 +777,10 @@ PERL_CALLCONV int	Perl_magic_existspack(pTHX_ SV* sv, MAGIC* mg);
 PERL_CALLCONV int	Perl_magic_freeregexp(pTHX_ SV* sv, MAGIC* mg);
 PERL_CALLCONV int	Perl_magic_freeovrld(pTHX_ SV* sv, MAGIC* mg);
 PERL_CALLCONV int	Perl_magic_get(pTHX_ SV* sv, MAGIC* mg);
-PERL_CALLCONV int	Perl_magic_getarylen(pTHX_ SV* sv, MAGIC* mg);
+PERL_CALLCONV int	Perl_magic_getarylen(pTHX_ SV* sv, MAGIC* mg)
+			__attribute__nonnull__(pTHX_1)
+			__attribute__nonnull__(pTHX_2);
+
 PERL_CALLCONV int	Perl_magic_getdefelem(pTHX_ SV* sv, MAGIC* mg);
 PERL_CALLCONV int	Perl_magic_getglob(pTHX_ SV* sv, MAGIC* mg);
 PERL_CALLCONV int	Perl_magic_getnkeys(pTHX_ SV* sv, MAGIC* mg);
@@ -1096,7 +1097,8 @@ PERL_CALLCONV SV*	Perl_newSVpvf(pTHX_ const char* pat, ...)
 PERL_CALLCONV SV*	Perl_vnewSVpvf(pTHX_ const char* pat, va_list* args);
 PERL_CALLCONV SV*	Perl_newSVrv(pTHX_ SV* rv, const char* classname)
 			__attribute__malloc__
-			__attribute__warn_unused_result__;
+			__attribute__warn_unused_result__
+			__attribute__nonnull__(pTHX_1);
 
 PERL_CALLCONV SV*	Perl_newSVsv(pTHX_ SV* old)
 			__attribute__malloc__
@@ -1185,15 +1187,11 @@ PERL_CALLCONV HV*	Perl_get_hv(pTHX_ const char* name, I32 create);
 PERL_CALLCONV CV*	Perl_get_cv(pTHX_ const char* name, I32 create);
 PERL_CALLCONV int	Perl_init_i18nl10n(pTHX_ int printwarn);
 PERL_CALLCONV int	Perl_init_i18nl14n(pTHX_ int printwarn);
-PERL_CALLCONV void	Perl_new_collate(pTHX_ char* newcoll)
-			__attribute__nonnull__(pTHX_1);
-
+PERL_CALLCONV void	Perl_new_collate(pTHX_ char* newcoll);
 PERL_CALLCONV void	Perl_new_ctype(pTHX_ char* newctype)
 			__attribute__nonnull__(pTHX_1);
 
-PERL_CALLCONV void	Perl_new_numeric(pTHX_ char* newcoll)
-			__attribute__nonnull__(pTHX_1);
-
+PERL_CALLCONV void	Perl_new_numeric(pTHX_ char* newcoll);
 PERL_CALLCONV void	Perl_set_numeric_local(pTHX);
 PERL_CALLCONV void	Perl_set_numeric_radix(pTHX);
 PERL_CALLCONV void	Perl_set_numeric_standard(pTHX);
@@ -1532,7 +1530,8 @@ PERL_CALLCONV MAGIC *	Perl_sv_magicext(pTHX_ SV* sv, SV* obj, int how, MGVTBL *v
 			__attribute__nonnull__(pTHX_1);
 
 PERL_CALLCONV SV*	Perl_sv_mortalcopy(pTHX_ SV* oldsv)
-			__attribute__nonnull__(pTHX_1);
+			__attribute__malloc__
+			__attribute__warn_unused_result__;
 
 PERL_CALLCONV SV*	Perl_sv_newmortal(pTHX)
 			__attribute__warn_unused_result__;
@@ -1576,7 +1575,9 @@ PERL_CALLCONV SV*	Perl_sv_setref_iv(pTHX_ SV* rv, const char* classname, IV iv);
 PERL_CALLCONV SV*	Perl_sv_setref_uv(pTHX_ SV* rv, const char* classname, UV uv);
 PERL_CALLCONV SV*	Perl_sv_setref_nv(pTHX_ SV* rv, const char* classname, NV nv);
 PERL_CALLCONV SV*	Perl_sv_setref_pv(pTHX_ SV* rv, const char* classname, void* pv);
-PERL_CALLCONV SV*	Perl_sv_setref_pvn(pTHX_ SV* rv, const char* classname, char* pv, STRLEN n);
+PERL_CALLCONV SV*	Perl_sv_setref_pvn(pTHX_ SV* rv, const char* classname, char* pv, STRLEN n)
+			__attribute__nonnull__(pTHX_3);
+
 PERL_CALLCONV void	Perl_sv_setpv(pTHX_ SV* sv, const char* ptr);
 PERL_CALLCONV void	Perl_sv_setpvn(pTHX_ SV* sv, const char* ptr, STRLEN len)
 			__attribute__nonnull__(pTHX_1);
@@ -1616,7 +1617,9 @@ PERL_CALLCONV NV	Perl_str_to_version(pTHX_ SV *sv);
 PERL_CALLCONV SV*	Perl_swash_init(pTHX_ char* pkg, char* name, SV* listsv, I32 minbits, I32 none);
 PERL_CALLCONV UV	Perl_swash_fetch(pTHX_ SV *sv, U8 *ptr, bool do_utf8);
 PERL_CALLCONV void	Perl_taint_env(pTHX);
-PERL_CALLCONV void	Perl_taint_proper(pTHX_ const char* f, const char* s);
+PERL_CALLCONV void	Perl_taint_proper(pTHX_ const char* f, const char* s)
+			__attribute__nonnull__(pTHX_2);
+
 PERL_CALLCONV UV	Perl_to_utf8_case(pTHX_ U8 *p, U8* ustrp, STRLEN *lenp, SV **swash, char *normal, char *special)
 			__attribute__nonnull__(pTHX_1)
 			__attribute__nonnull__(pTHX_2);
@@ -1768,16 +1771,33 @@ PERL_CALLCONV void	Perl_sv_usepvn_mg(pTHX_ SV *sv, char *ptr, STRLEN len);
 PERL_CALLCONV MGVTBL*	Perl_get_vtbl(pTHX_ int vtbl_id);
 PERL_CALLCONV char*	Perl_pv_display(pTHX_ SV *dsv, char *pv, STRLEN cur, STRLEN len, STRLEN pvlim);
 PERL_CALLCONV void	Perl_dump_indent(pTHX_ I32 level, PerlIO *file, const char* pat, ...)
-			__attribute__format__(__printf__,pTHX_3,pTHX_4);
-
-PERL_CALLCONV void	Perl_dump_vindent(pTHX_ I32 level, PerlIO *file, const char* pat, va_list *args);
-PERL_CALLCONV void	Perl_do_gv_dump(pTHX_ I32 level, PerlIO *file, char *name, GV *sv);
-PERL_CALLCONV void	Perl_do_gvgv_dump(pTHX_ I32 level, PerlIO *file, char *name, GV *sv);
-PERL_CALLCONV void	Perl_do_hv_dump(pTHX_ I32 level, PerlIO *file, char *name, HV *sv);
-PERL_CALLCONV void	Perl_do_magic_dump(pTHX_ I32 level, PerlIO *file, MAGIC *mg, I32 nest, I32 maxnest, bool dumpops, STRLEN pvlim);
-PERL_CALLCONV void	Perl_do_op_dump(pTHX_ I32 level, PerlIO *file, OP *o);
-PERL_CALLCONV void	Perl_do_pmop_dump(pTHX_ I32 level, PerlIO *file, PMOP *pm);
-PERL_CALLCONV void	Perl_do_sv_dump(pTHX_ I32 level, PerlIO *file, SV *sv, I32 nest, I32 maxnest, bool dumpops, STRLEN pvlim);
+			__attribute__format__(__printf__,pTHX_3,pTHX_4)
+			__attribute__nonnull__(pTHX_2);
+
+PERL_CALLCONV void	Perl_dump_vindent(pTHX_ I32 level, PerlIO *file, const char* pat, va_list *args)
+			__attribute__nonnull__(pTHX_2);
+
+PERL_CALLCONV void	Perl_do_gv_dump(pTHX_ I32 level, PerlIO *file, char *name, GV *sv)
+			__attribute__nonnull__(pTHX_2);
+
+PERL_CALLCONV void	Perl_do_gvgv_dump(pTHX_ I32 level, PerlIO *file, char *name, GV *sv)
+			__attribute__nonnull__(pTHX_2);
+
+PERL_CALLCONV void	Perl_do_hv_dump(pTHX_ I32 level, PerlIO *file, char *name, HV *sv)
+			__attribute__nonnull__(pTHX_2);
+
+PERL_CALLCONV void	Perl_do_magic_dump(pTHX_ I32 level, PerlIO *file, MAGIC *mg, I32 nest, I32 maxnest, bool dumpops, STRLEN pvlim)
+			__attribute__nonnull__(pTHX_2);
+
+PERL_CALLCONV void	Perl_do_op_dump(pTHX_ I32 level, PerlIO *file, OP *o)
+			__attribute__nonnull__(pTHX_2);
+
+PERL_CALLCONV void	Perl_do_pmop_dump(pTHX_ I32 level, PerlIO *file, PMOP *pm)
+			__attribute__nonnull__(pTHX_2);
+
+PERL_CALLCONV void	Perl_do_sv_dump(pTHX_ I32 level, PerlIO *file, SV *sv, I32 nest, I32 maxnest, bool dumpops, STRLEN pvlim)
+			__attribute__nonnull__(pTHX_2);
+
 PERL_CALLCONV void	Perl_magic_dump(pTHX_ MAGIC *mg);
 #if defined(PERL_FLEXIBLE_EXCEPTIONS)
 PERL_CALLCONV void*	Perl_default_protect(pTHX_ volatile JMPENV *je, int *excpt, protect_body_t body, ...);
@@ -1996,6 +2016,13 @@ STATIC int	S_magic_methcall(pTHX_ SV *sv, const MAGIC *mg, const char *meth, I32
 			__attribute__nonnull__(pTHX_2)
 			__attribute__nonnull__(pTHX_3);
 
+STATIC void	S_restore_magic(pTHX_ const void *p)
+			__attribute__nonnull__(pTHX_1);
+
+STATIC void	S_unwind_handler_stack(pTHX_ const void *p)
+			__attribute__nonnull__(pTHX_1);
+
+
 #endif
 
 #if defined(PERL_IN_OP_C) || defined(PERL_DECL_PROT)
@@ -2377,8 +2404,14 @@ STATIC SV*	S_save_scalar_at(pTHX_ SV **sptr);
 #endif
 
 #if defined(PERL_IN_SV_C) || defined(PERL_DECL_PROT)
-STATIC IV	S_asIV(pTHX_ SV* sv);
-STATIC UV	S_asUV(pTHX_ SV* sv);
+STATIC IV	S_asIV(pTHX_ SV* sv)
+			__attribute__warn_unused_result__
+			__attribute__nonnull__(pTHX_1);
+
+STATIC UV	S_asUV(pTHX_ SV* sv)
+			__attribute__warn_unused_result__
+			__attribute__nonnull__(pTHX_1);
+
 STATIC XPVIV*	S_new_xiv(pTHX);
 STATIC XPVNV*	S_new_xnv(pTHX);
 STATIC XPV*	S_new_xpv(pTHX);
@@ -2405,11 +2438,22 @@ STATIC void	S_del_xpvgv(pTHX_ XPVGV* p);
 STATIC void	S_del_xpvlv(pTHX_ XPVLV* p);
 STATIC void	S_del_xpvbm(pTHX_ XPVBM* p);
 STATIC void	S_del_xrv(pTHX_ XRV* p);
-STATIC void	S_sv_unglob(pTHX_ SV* sv);
-STATIC void	S_not_a_number(pTHX_ SV *sv);
-STATIC I32	S_visit(pTHX_ SVFUNC_t f, U32 flags, U32 mask);
-STATIC void	S_sv_add_backref(pTHX_ SV *tsv, SV *sv);
-STATIC void	S_sv_del_backref(pTHX_ SV *sv);
+STATIC void	S_sv_unglob(pTHX_ SV* sv)
+			__attribute__nonnull__(pTHX_1);
+
+STATIC void	S_not_a_number(pTHX_ SV *sv)
+			__attribute__nonnull__(pTHX_1);
+
+STATIC I32	S_visit(pTHX_ SVFUNC_t f, U32 flags, U32 mask)
+			__attribute__nonnull__(pTHX_1);
+
+STATIC void	S_sv_add_backref(pTHX_ SV *tsv, SV *sv)
+			__attribute__nonnull__(pTHX_1)
+			__attribute__nonnull__(pTHX_2);
+
+STATIC void	S_sv_del_backref(pTHX_ SV *sv)
+			__attribute__nonnull__(pTHX_1);
+
 #  ifdef DEBUGGING
 STATIC void	S_del_sv(pTHX_ SV *p);
 #  endif
@@ -2509,11 +2553,15 @@ STATIC SV*	S_isa_lookup(pTHX_ HV *stash, const char *name, HV *name_stash, int l
 #endif
 
 #if defined(PERL_IN_LOCALE_C) || defined(PERL_DECL_PROT)
-STATIC char*	S_stdize_locale(pTHX_ char* locs);
+STATIC char*	S_stdize_locale(pTHX_ char* locs)
+			__attribute__nonnull__(pTHX_1);
+
 #endif
 
 #if defined(PERL_IN_UTIL_C) || defined(PERL_DECL_PROT)
-STATIC COP*	S_closest_cop(pTHX_ COP *cop, OP *o);
+STATIC COP*	S_closest_cop(pTHX_ COP *cop, const OP *o)
+			__attribute__nonnull__(pTHX_1);
+
 STATIC SV*	S_mess_alloc(pTHX);
 #endif
 
diff --git a/scope.c b/scope.c
index 3869104b1b..ceba5db347 100644
--- a/scope.c
+++ b/scope.c
@@ -502,7 +502,7 @@ Perl_save_threadsv(pTHX_ PADOFFSET i)
     return svp;
 #else
     Perl_croak(aTHX_ "panic: save_threadsv called in non-threaded perl");
-    (void)i;
+    PERL_UNUSED_ARG(i);
     NORETURN_FUNCTION_END;
 #endif /* USE_5005THREADS */
 }
diff --git a/taint.c b/taint.c
index 79b3350d0c..16bbd4be65 100644
--- a/taint.c
+++ b/taint.c
@@ -24,24 +24,22 @@
 void
 Perl_taint_proper(pTHX_ const char *f, const char *s)
 {
-    const char *ug;
-
 #if defined(HAS_SETEUID) && defined(DEBUGGING)
 #   if Uid_t_size == 1
     {
-	 UV  uid = PL_uid;
-	 UV euid = PL_euid;
+	const UV  uid = PL_uid;
+	const UV euid = PL_euid;
 
-	 DEBUG_u(PerlIO_printf(Perl_debug_log,
+	DEBUG_u(PerlIO_printf(Perl_debug_log,
 			       "%s %d %"UVuf" %"UVuf"\n",
 			       s, PL_tainted, uid, euid));
     }
 #   else
     {
-	 IV  uid = PL_uid;
-	 IV euid = PL_euid;
+	const IV  uid = PL_uid;
+	const IV euid = PL_euid;
 
-	 DEBUG_u(PerlIO_printf(Perl_debug_log,
+	DEBUG_u(PerlIO_printf(Perl_debug_log,
 			       "%s %d %"IVdf" %"IVdf"\n",
 			       s, PL_tainted, uid, euid));
     }
@@ -49,6 +47,8 @@ Perl_taint_proper(pTHX_ const char *f, const char *s)
 #endif
 
     if (PL_tainted) {
+	const char *ug;
+
 	if (!f)
 	    f = PL_no_security;
 	if (PL_euid != PL_uid)
@@ -91,7 +91,7 @@ Perl_taint_env(pTHX)
     if (!GvHV(PL_envgv) || !(SvRMAGICAL(GvHV(PL_envgv))
 	    && mg_find((SV*)GvHV(PL_envgv), PERL_MAGIC_env))) {
 	const bool was_tainted = PL_tainted;
-        const char *name = GvENAME(PL_envgv);
+	const char * const name = GvENAME(PL_envgv);
 	PL_tainted = TRUE;
 	if (strEQ(name,"ENV"))
 	    /* hash alias */
@@ -146,7 +146,7 @@ Perl_taint_env(pTHX)
 	STRLEN len;
 	const bool was_tainted = PL_tainted;
 	const char *t = SvPV_const(*svp, len);
-	const char *e = t + len;
+	const char * const e = t + len;
 	PL_tainted = was_tainted;
 	if (t < e && isALNUM(*t))
 	    t++;
@@ -160,7 +160,7 @@ Perl_taint_env(pTHX)
 #endif /* !VMS */
 
     for (e = misc_env; *e; e++) {
-	svp = hv_fetch(GvHVn(PL_envgv), *e, strlen(*e), FALSE);
+	SV ** const svp = hv_fetch(GvHVn(PL_envgv), *e, strlen(*e), FALSE);
 	if (svp && *svp != &PL_sv_undef && SvTAINTED(*svp)) {
 	    TAINT;
 	    taint_proper("Insecure $ENV{%s}%s", *e);
diff --git a/util.c b/util.c
index b6cb13ae31..0d149cd028 100644
--- a/util.c
+++ b/util.c
@@ -947,7 +947,7 @@ Perl_mess(pTHX_ const char *pat, ...)
 }
 
 STATIC COP*
-S_closest_cop(pTHX_ COP *cop, OP *o)
+S_closest_cop(pTHX_ COP *cop, const OP *o)
 {
     /* Look for PL_op starting from o.  cop is the last COP we've seen. */
 
@@ -974,7 +974,7 @@ S_closest_cop(pTHX_ COP *cop, OP *o)
 
     /* Nothing found. */
 
-    return 0;
+    return Null(COP *);
 }
 
 SV *
@@ -2996,7 +2996,7 @@ Perl_set_context(void *t)
 	Perl_croak_nocontext("panic: pthread_setspecific");
 #  endif
 #else
-    (void)t;
+    PERL_UNUSED_ARG(t);
 #endif
 }
 
@@ -3322,7 +3322,7 @@ Perl_get_ppaddr(pTHX)
 char *
 Perl_getenv_len(pTHX_ const char *env_elem, unsigned long *len)
 {
-    char *env_trans = PerlEnv_getenv(env_elem);
+    char * const env_trans = PerlEnv_getenv(env_elem);
     if (env_trans)
 	*len = strlen(env_trans);
     return env_trans;