Empty sublex_info into the parser struct

sublex_info is never validly copied or set* all at once and no pointer
is ever taken to it.  It seems to be left over from the time when
PL_sublex_info was a global variable.  (Indeed, the struct is still
defined in perl.h, an odd place for something used only by parser.h.)

It will be easier to eliminate alignment holes in the parser struct if
we just empty it out.

* The one instance of sublex_info being copied, in
sv.c:Perl_parser_dup, ended up potentially sharing an SV between
threads, which is a no-no.  I say potentially, because I can’t see how
it could be non-null during thread cloning, which would have to happen
between sublex_start and sublex_push.

4 files changed, 32 insertions, 35 deletions

diff --git a/parser.h b/parser.h
index 5d0f0025b3..135051d87f 100644
--- a/parser.h
+++ b/parser.h
@@ -72,7 +72,10 @@ typedef struct yy_parser {
     bool	preambled;
     bool        lex_re_reparsing; /* we're doing G_RE_REPARSING */
     I32		lex_allbrackets;/* (), [], {}, ?: bracket count */
-    SUBLEXINFO	sublex_info;
+    U8		lex_super_state;/* lexer state to save */
+    U16		lex_sub_inwhat;	/* "lex_inwhat" to use in sublex_push */
+    OP		*lex_sub_op;	/* current op in y/// or pattern */
+    SV		*lex_sub_repl;	/* repl of s/// used in sublex_push */
     LEXSHARED	*lex_shared;
     SV		*linestr;	/* current chunk of src text */
     char	*bufptr;	/* carries the cursor (current parsing
diff --git a/perl.h b/perl.h
index 218f94c74d..1a38933ec9 100644
--- a/perl.h
+++ b/perl.h
@@ -3919,14 +3919,6 @@ typedef        struct crypt_data {     /* straight from /usr/include/crypt.h */
 #undef _XPVMG_HEAD
 #undef _XPVCV_COMMON
 
-typedef struct _sublex_info SUBLEXINFO;
-struct _sublex_info {
-    U8 super_state;	/* lexer state to save */
-    U16 sub_inwhat;	/* "lex_inwhat" to use */
-    OP *sub_op;		/* "lex_op" to use */
-    SV *repl;		/* replacement of s/// or y/// */
-};
-
 #include "parser.h"
 
 typedef struct magic_state MGS;	/* struct magic_state defined in mg.c */
diff --git a/sv.c b/sv.c
index a0d5d7b7ab..c77a8bb570 100644
--- a/sv.c
+++ b/sv.c
@@ -12966,7 +12966,10 @@ Perl_parser_dup(pTHX_ const yy_parser *const proto, CLONE_PARAMS *const param)
     parser->multi_start	= proto->multi_start;
     parser->multi_end	= proto->multi_end;
     parser->preambled	= proto->preambled;
-    parser->sublex_info	= proto->sublex_info; /* XXX not quite right */
+    parser->lex_super_state = proto->lex_super_state;
+    parser->lex_sub_inwhat  = proto->lex_sub_inwhat;
+    parser->lex_sub_op	= proto->lex_sub_op;
+    parser->lex_sub_repl= sv_dup_inc(proto->lex_sub_repl, param);
     parser->linestr	= sv_dup_inc(proto->linestr, param);
     parser->expect	= proto->expect;
     parser->copline	= proto->copline;
diff --git a/toke.c b/toke.c
index 288a6304c6..440353cf00 100644
--- a/toke.c
+++ b/toke.c
@@ -64,7 +64,6 @@ Individual members of C<PL_parser> have their own documentation.
 #define PL_multi_open		(PL_parser->multi_open)
 #define PL_multi_close		(PL_parser->multi_close)
 #define PL_preambled		(PL_parser->preambled)
-#define PL_sublex_info		(PL_parser->sublex_info)
 #define PL_linestr		(PL_parser->linestr)
 #define PL_expect		(PL_parser->expect)
 #define PL_copline		(PL_parser->copline)
@@ -774,7 +773,7 @@ Perl_parser_free(pTHX_  const yy_parser *parser)
 	PerlIO_close(parser->rsfp);
     SvREFCNT_dec(parser->rsfp_filters);
     SvREFCNT_dec(parser->lex_stuff);
-    SvREFCNT_dec(parser->sublex_info.repl);
+    SvREFCNT_dec(parser->lex_sub_repl);
 
     Safefree(parser->lex_brackstack);
     Safefree(parser->lex_casestack);
@@ -2316,9 +2315,9 @@ S_sublex_start(pTHX)
 	return THING;
     }
 
-    PL_sublex_info.super_state = PL_lex_state;
-    PL_sublex_info.sub_inwhat = (U16)op_type;
-    PL_sublex_info.sub_op = PL_lex_op;
+    PL_parser->lex_super_state = PL_lex_state;
+    PL_parser->lex_sub_inwhat = (U16)op_type;
+    PL_parser->lex_sub_op = PL_lex_op;
     PL_lex_state = LEX_INTERPPUSH;
 
     PL_expect = XTERM;
@@ -2346,7 +2345,7 @@ S_sublex_push(pTHX)
     const bool is_heredoc = PL_multi_close == '<';
     ENTER;
 
-    PL_lex_state = PL_sublex_info.super_state;
+    PL_lex_state = PL_parser->lex_super_state;
     SAVEI8(PL_lex_dojoin);
     SAVEI32(PL_lex_brackets);
     SAVEI32(PL_lex_allbrackets);
@@ -2388,16 +2387,16 @@ S_sublex_push(pTHX)
     PL_parser->lex_shared->ls_bufptr  = PL_bufptr;
 
     PL_linestr = PL_lex_stuff;
-    PL_lex_repl = PL_sublex_info.repl;
+    PL_lex_repl = PL_parser->lex_sub_repl;
     PL_lex_stuff = NULL;
-    PL_sublex_info.repl = NULL;
+    PL_parser->lex_sub_repl = NULL;
 
     /* Arrange for PL_lex_stuff to be freed on scope exit, in case it gets
        set for an inner quote-like operator and then an error causes scope-
        popping.  We must not have a PL_lex_stuff value left dangling, as
        that breaks assumptions elsewhere.  See bug #123617.  */
     SAVEGENERICSV(PL_lex_stuff);
-    SAVEGENERICSV(PL_sublex_info.repl);
+    SAVEGENERICSV(PL_parser->lex_sub_repl);
 
     PL_bufend = PL_bufptr = PL_oldbufptr = PL_oldoldbufptr = PL_linestart
 	= SvPVX(PL_linestr);
@@ -2424,10 +2423,10 @@ S_sublex_push(pTHX)
     shared->ls_prev = PL_parser->lex_shared;
     PL_parser->lex_shared = shared;
 
-    PL_lex_inwhat = PL_sublex_info.sub_inwhat;
+    PL_lex_inwhat = PL_parser->lex_sub_inwhat;
     if (PL_lex_inwhat == OP_TRANSR) PL_lex_inwhat = OP_TRANS;
     if (PL_lex_inwhat == OP_MATCH || PL_lex_inwhat == OP_QR || PL_lex_inwhat == OP_SUBST)
-	PL_lex_inpat = PL_sublex_info.sub_op;
+	PL_lex_inpat = PL_parser->lex_sub_op;
     else
 	PL_lex_inpat = NULL;
 
@@ -2857,10 +2856,10 @@ S_scan_const(pTHX_ char *start)
     PERL_ARGS_ASSERT_SCAN_CONST;
 
     assert(PL_lex_inwhat != OP_TRANSR);
-    if (PL_lex_inwhat == OP_TRANS && PL_sublex_info.sub_op) {
+    if (PL_lex_inwhat == OP_TRANS && PL_parser->lex_sub_op) {
 	/* If we are doing a trans and we know we want UTF8 set expectation */
-	has_utf8   = PL_sublex_info.sub_op->op_private & (OPpTRANS_FROM_UTF|OPpTRANS_TO_UTF);
-	this_utf8  = PL_sublex_info.sub_op->op_private & (PL_lex_repl ? OPpTRANS_FROM_UTF : OPpTRANS_TO_UTF);
+	has_utf8   = PL_parser->lex_sub_op->op_private & (OPpTRANS_FROM_UTF|OPpTRANS_TO_UTF);
+	this_utf8  = PL_parser->lex_sub_op->op_private & (PL_lex_repl ? OPpTRANS_FROM_UTF : OPpTRANS_TO_UTF);
     }
 
     /* Protect sv from errors and fatal warnings. */
@@ -3399,9 +3398,9 @@ S_scan_const(pTHX_ char *start)
 
 		        d = (char*)uvchr_to_utf8((U8*)d, uv);
 			if (PL_lex_inwhat == OP_TRANS
-                            && PL_sublex_info.sub_op)
+                            && PL_parser->lex_sub_op)
                         {
-			    PL_sublex_info.sub_op->op_private |=
+			    PL_parser->lex_sub_op->op_private |=
 				(PL_lex_repl ? OPpTRANS_FROM_UTF
 					     : OPpTRANS_TO_UTF);
 			}
@@ -3814,8 +3813,8 @@ S_scan_const(pTHX_ char *start)
     SvPOK_on(sv);
     if (has_utf8) {
 	SvUTF8_on(sv);
-	if (PL_lex_inwhat == OP_TRANS && PL_sublex_info.sub_op) {
-	    PL_sublex_info.sub_op->op_private |=
+	if (PL_lex_inwhat == OP_TRANS && PL_parser->lex_sub_op) {
+	    PL_parser->lex_sub_op->op_private |=
 		    (PL_lex_repl ? OPpTRANS_FROM_UTF : OPpTRANS_TO_UTF);
 	}
     }
@@ -9323,15 +9322,15 @@ S_scan_subst(pTHX_ char *start)
 		sv_catpvs(repl, "do ");
 	}
 	sv_catpvs(repl, "{");
-	sv_catsv(repl, PL_sublex_info.repl);
+	sv_catsv(repl, PL_parser->lex_sub_repl);
 	sv_catpvs(repl, "}");
 	SvEVALED_on(repl);
-	SvREFCNT_dec(PL_sublex_info.repl);
-	PL_sublex_info.repl = repl;
+	SvREFCNT_dec(PL_parser->lex_sub_repl);
+	PL_parser->lex_sub_repl = repl;
     }
     if (CopLINE(PL_curcop) != first_line) {
-	sv_upgrade(PL_sublex_info.repl, SVt_PVNV);
-	((XPVNV*)SvANY(PL_sublex_info.repl))->xnv_u.xpad_cop_seq.xlow =
+	sv_upgrade(PL_parser->lex_sub_repl, SVt_PVNV);
+	((XPVNV*)SvANY(PL_parser->lex_sub_repl))->xnv_u.xpad_cop_seq.xlow =
 	    CopLINE(PL_curcop) - first_line;
 	CopLINE_set(PL_curcop, first_line);
     }
@@ -9395,7 +9394,7 @@ S_scan_trans(pTHX_ char *start)
     o->op_private &= ~OPpTRANS_ALL;
     o->op_private |= del|squash|complement|
       (DO_UTF8(PL_lex_stuff)? OPpTRANS_FROM_UTF : 0)|
-      (DO_UTF8(PL_sublex_info.repl) ? OPpTRANS_TO_UTF   : 0);
+      (DO_UTF8(PL_parser->lex_sub_repl) ? OPpTRANS_TO_UTF   : 0);
 
     PL_lex_op = o;
     pl_yylval.ival = nondestruct ? OP_TRANSR : OP_TRANS;
@@ -10113,7 +10112,7 @@ S_scan_str(pTHX_ char *start, int keep_bracketed_quoted, int keep_delims, int re
     */
 
     if (PL_lex_stuff)
-	PL_sublex_info.repl = sv;
+	PL_parser->lex_sub_repl = sv;
     else
 	PL_lex_stuff = sv;
     if (delimp) *delimp = PL_multi_open == PL_multi_close ? s-termlen : s;