reorder intrpvar.h

Move more of the more commonly-used PL_ variables towards the front of the
file (and thus to the top of the interpreter struct on MULTIPLICITY
builds).

This helps ensure that "hot" variables are clustered together on the same
small number of cache lines, and also that the machine code to load them
will have shorter offsets, which on some architectures may be achieved
with shorter instructions.

The "hotness" has been determined purely by my subjective judgement rather
than any profiling. It's still open for the later to be done.

(Only simple shunting of whole lines has been done; no changes have been
made to individual lines.)

1 files changed, 117 insertions, 109 deletions

diff --git a/intrpvar.h b/intrpvar.h
index 6865ab97cc..b5902a5a41 100644
--- a/intrpvar.h
+++ b/intrpvar.h
@@ -43,32 +43,110 @@ PERLVAR(I, curpad,	SV **)		/* active pad (lexicals+tmps) */
 PERLVAR(I, stack_base,	SV **)
 PERLVAR(I, stack_max,	SV **)
 
-PERLVAR(I, scopestack,	I32 *)		/* scopes we've ENTERed */
-/* name of the scopes we've ENTERed. Only used with -DDEBUGGING, but needs to be
-   present always, as -DDEBUGGING must be binary compatible with non.  */
-PERLVARI(I, scopestack_name, const char * *, NULL)
-PERLVAR(I, scopestack_ix, I32)
-PERLVAR(I, scopestack_max, I32)
-
 PERLVAR(I, savestack,	ANY *)		/* items that need to be restored when
 					   LEAVEing scopes we've ENTERed */
 PERLVAR(I, savestack_ix, I32)
 PERLVAR(I, savestack_max, I32)
 
+PERLVAR(I, scopestack,	I32 *)		/* scopes we've ENTERed */
+PERLVAR(I, scopestack_ix, I32)
+PERLVAR(I, scopestack_max, I32)
+
 PERLVAR(I, tmps_stack,	SV **)		/* mortals we've made */
 PERLVARI(I, tmps_ix,	I32,	-1)
 PERLVARI(I, tmps_floor,	I32,	-1)
 PERLVAR(I, tmps_max,	I32)
-PERLVAR(I, modcount,	I32)		/* how much op_lvalue()ification in
-					   assignment? */
+
+PERLVARI(I, sub_generation, U32, 1)	/* incr to invalidate method cache */
 
 PERLVAR(I, markstack,	I32 *)		/* stack_sp locations we're
 					   remembering */
 PERLVAR(I, markstack_ptr, I32 *)
 PERLVAR(I, markstack_max, I32 *)
 
+PERLVAR(I, strtab,	HV *)		/* shared string table */
+
+/* Fields used by magic variables such as $@, $/ and so on */
+PERLVAR(I, curpm,	PMOP *)		/* what to do \ interps in REs from */
+
+PERLVAR(I, tainting,	bool)		/* doing taint checks */
+PERLVAR(I, tainted,	bool)		/* using variables controlled by $< */
+PERLVAR(I, delaymagic,	U16)		/* ($<,$>) = ... */
+PERLVAR(I, localizing,	U8)		/* are we processing a local() list? */
+PERLVAR(I, in_eval,	U8)		/* trap "fatal" errors? */
+/*
+
+=for apidoc mn|bool|PL_dowarn
+
+The C variable which corresponds to Perl's $^W warning variable.
+
+=cut
+*/
+
+PERLVAR(I, dowarn,	U8)
+
+#if defined (PERL_UTF8_CACHE_ASSERT) || defined (DEBUGGING)
+#  define PERL___I -1
+#else
+#  define PERL___I 1
+#endif
+PERLVARI(I, utf8cache, I8, PERL___I)	/* Is the utf8 caching code enabled? */
+#undef PERL___I
+
+
+/* Stashes */
+PERLVAR(I, defstash,	HV *)		/* main symbol table */
+PERLVAR(I, curstash,	HV *)		/* symbol table for current package */
+
+PERLVAR(I, curcop,	COP *)
+PERLVAR(I, curstack,	AV *)		/* THE STACK */
+PERLVAR(I, curstackinfo, PERL_SI *)	/* current stack + context */
+PERLVAR(I, mainstack,	AV *)		/* the stack when nothing funny is
+					   happening */
+
+/* memory management */
+PERLVAR(I, sv_count,	IV)		/* how many SV* are currently allocated */
+PERLVAR(I, sv_objcount,	IV)		/* DEPRECATED AND UNMAINTAINED.
+                                         * Will be removed in Perl 5.20.
+                                         * Used to be: how many objects are currently allocated. */
+
+PERLVAR(I, sv_root,	SV *)		/* storage for SVs belonging to interp */
+PERLVAR(I, sv_arenaroot, SV *)		/* list of areas for garbage collection */
+
+PERLVAR(I, reg_state,	struct re_save_state)
+
+/* the currently active slab in a chain of slabs of regmatch states,
+ * and the currently active state within that slab */
+
+PERLVARI(I, regmatch_slab, regmatch_slab *,	NULL)
+PERLVAR(I, regmatch_state, regmatch_state *)
+
+PERLVAR(I, comppad,	PAD *)		/* storage for lexically scoped temporaries */
+
+/*
+=for apidoc Amn|SV|PL_sv_undef
+This is the C<undef> SV.  Always refer to this as C<&PL_sv_undef>.
+
+=for apidoc Amn|SV|PL_sv_no
+This is the C<false> SV.  See C<PL_sv_yes>.  Always refer to this as
+C<&PL_sv_no>.
+
+=for apidoc Amn|SV|PL_sv_yes
+This is the C<true> SV.  See C<PL_sv_no>.  Always refer to this as
+C<&PL_sv_yes>.
+
+=cut
+*/
+
+PERLVAR(I, sv_undef,	SV)
+PERLVAR(I, sv_no,	SV)
+PERLVAR(I, sv_yes,	SV)
 PERLVAR(I, Sv,		SV *)		/* used to hold temporary values */
-PERLVAR(I, Xpv,		XPV *)		/* used to hold temporary values */
+
+PERLVAR(I, parser,	yy_parser *)	/* current parser state */
+
+PERLVAR(I, stashcache,	HV *)		/* Cache to speed up S_method_common */
+
 
 /*
 =for apidoc Amn|STRLEN|PL_na
@@ -94,9 +172,6 @@ PERLVARI(I, statname,	SV *,	NULL)
 PERLVAR(I, timesbuf,	struct tms)
 #endif
 
-/* Fields used by magic variables such as $@, $/ and so on */
-PERLVAR(I, curpm,	PMOP *)		/* what to do \ interps in REs from */
-
 /*
 =for apidoc mn|SV*|PL_rs
 
@@ -122,17 +197,9 @@ PERLVAR(I, formtarget,	SV *)
 PERLVAR(I, bodytarget,	SV *)
 PERLVAR(I, toptarget,	SV *)
 
-/* Stashes */
-PERLVAR(I, defstash,	HV *)		/* main symbol table */
-PERLVAR(I, curstash,	HV *)		/* symbol table for current package */
 
 PERLVAR(I, restartop,	OP *)		/* propagating an error from croak? */
 PERLVAR(I, restartjmpenv, JMPENV *)	/* target frame for longjmp in die */
-PERLVAR(I, curcop,	COP *)
-PERLVAR(I, curstack,	AV *)		/* THE STACK */
-PERLVAR(I, curstackinfo, PERL_SI *)	/* current stack + context */
-PERLVAR(I, mainstack,	AV *)		/* the stack when nothing funny is
-					   happening */
 
 PERLVAR(I, top_env,	JMPENV *)	/* ptr to current sigjmp environment */
 PERLVAR(I, start_env,	JMPENV)		/* empty startup sigjmp environment */
@@ -153,10 +220,6 @@ PERLVAR(I, secondgv,	GV *)		/* $b */
 PERLVAR(I, efloatbuf,	char *)
 PERLVAR(I, efloatsize,	STRLEN)
 
-/* regex stuff */
-
-PERLVAR(I, reg_state,	struct re_save_state)
-
 PERLVAR(I, regdummy,	regnode)	/* from regcomp.c */
 
 PERLVARI(I, dumpindent,	U16,	4)	/* number of blanks per dump
@@ -232,29 +295,6 @@ PERLVARI(I, opfreehook,	Perl_ophook_t, 0) /* op_free() hook */
 PERLVARI(I, watchaddr,	char **, 0)
 PERLVAR(I, watchok,	char *)
 
-/* the currently active slab in a chain of slabs of regmatch states,
- * and the currently active state within that slab */
-
-PERLVARI(I, regmatch_slab, regmatch_slab *,	NULL)
-PERLVAR(I, regmatch_state, regmatch_state *)
-
-/* Put anything new that is pointer aligned here. */
-
-PERLVAR(I, delaymagic,	U16)		/* ($<,$>) = ... */
-PERLVAR(I, localizing,	U8)		/* are we processing a local() list? */
-PERLVAR(I, colorset,	bool)		/* from regcomp.c */
-PERLVAR(I, in_eval,	U8)		/* trap "fatal" errors? */
-PERLVAR(I, tainted,	bool)		/* using variables controlled by $< */
-PERLVAR(I, tainting,	bool)		/* doing taint checks */
-
-/* This value may be set when embedding for full cleanup  */
-/* 0=none, 1=full, 2=full with checks */
-/* mod_perl is special, and also assigns a meaning -1 */
-PERLVARI(I, perl_destruct_level, signed char,	0)
-
-/* current phase the interpreter is in */
-PERLVARI(I, phase,	enum perl_phase, PERL_PHASE_CONSTRUCT)
-
 PERLVAR(I, perldb,	U32)
 
 PERLVAR(I, signals,	U32)	/* Using which pre-5.8 signals */
@@ -284,23 +324,6 @@ PERLVAR(I, minus_F,	bool)
 PERLVAR(I, doswitches,	bool)
 PERLVAR(I, minus_E,	bool)
 
-/*
-
-=for apidoc mn|bool|PL_dowarn
-
-The C variable which corresponds to Perl's $^W warning variable.
-
-=cut
-*/
-
-PERLVAR(I, dowarn,	U8)
-#ifdef PERL_SAWAMPERSAND
-PERLVAR(I, sawampersand, U8)		/* must save all match strings */
-#endif
-PERLVAR(I, unsafe,	bool)
-
-/* Space for U16 (or U8 if PERL_SAWAMPERSAND is defined)  */
-
 PERLVAR(I, reentrant_retint, int)	/* Integer return value from reentrant functions */
 
 PERLVAR(I, inplace,	char *)
@@ -375,20 +398,10 @@ PERLVAR(I, endav,	AV *)		/* names of END subroutines */
 PERLVAR(I, unitcheckav,	AV *)		/* names of UNITCHECK subroutines */
 PERLVAR(I, checkav,	AV *)		/* names of CHECK subroutines */
 PERLVAR(I, initav,	AV *)		/* names of INIT subroutines */
-PERLVAR(I, strtab,	HV *)		/* shared string table */
-PERLVARI(I, sub_generation, U32, 1)	/* incr to invalidate method cache */
 
 /* funky return mechanisms */
 PERLVAR(I, forkprocess,	int)		/* so do_open |- can return proc# */
 
-/* memory management */
-PERLVAR(I, sv_count,	IV)		/* how many SV* are currently allocated */
-PERLVAR(I, sv_objcount,	IV)		/* DEPRECATED AND UNMAINTAINED.
-                                         * Will be removed in Perl 5.20.
-                                         * Used to be: how many objects are currently allocated. */
-PERLVAR(I, sv_root,	SV *)		/* storage for SVs belonging to interp */
-PERLVAR(I, sv_arenaroot, SV *)		/* list of areas for garbage collection */
-
 /* subprocess state */
 PERLVAR(I, fdpid,	AV *)		/* keep fd-to-pid mappings for my_popen */
 
@@ -417,13 +430,18 @@ PERLVAR(I, Cmd,		char *)		/* stuff to free from do_aexec, vfork safe */
 PERLVAR(I, preambleav,	AV *)
 PERLVAR(I, mess_sv,	SV *)
 PERLVAR(I, ors_sv,	SV *)		/* output record separator $\ */
+
 /* statics moved here for shared library purposes */
 PERLVARI(I, gensym,	I32,	0)	/* next symbol for getsym() to define */
 PERLVARI(I, cv_has_eval, bool, FALSE)	/* PL_compcv includes an entereval or similar */
 PERLVAR(I, taint_warn,	bool)		/* taint warns instead of dying */
 PERLVARI(I, laststype,	U16,	OP_STAT)
+
 PERLVARI(I, laststatval, int,	-1)
 
+PERLVAR(I, modcount,	I32)		/* how much op_lvalue()ification in
+					   assignment? */
+
 /* interpreter atexit processing */
 PERLVARI(I, exitlistlen, I32, 0)	/* length of same */
 PERLVARI(I, exitlist,	PerlExitListEntry *, NULL)
@@ -449,7 +467,6 @@ PERLVARI(I, profiledata, U32 *,	NULL)	/* table of ops, counts */
 PERLVAR(I, compiling,	COP)		/* compiling/done executing marker */
 
 PERLVAR(I, compcv,	CV *)		/* currently compiling subroutine */
-PERLVAR(I, comppad,	PAD *)		/* storage for lexically scoped temporaries */
 PERLVAR(I, comppad_name, PADNAMELIST *)	/* variable names for "my" variables */
 PERLVAR(I, comppad_name_fill,	I32)	/* last "introduced" variable offset */
 PERLVAR(I, comppad_name_floor,	I32)	/* start of vars in innermost block */
@@ -463,11 +480,14 @@ PERLVAR(I, sys_intern,	struct interp_intern)
 PERLVAR(I, DBcv,	CV *)		/* from perl.c */
 PERLVARI(I, generation,	int,	100)	/* from op.c */
 
+PERLVAR(I, unicode, U32)	/* Unicode features: $ENV{PERL_UNICODE} or -C */
+
 PERLVARI(I, in_clean_objs,bool,    FALSE)	/* from sv.c */
 PERLVARI(I, in_clean_all, bool,    FALSE)	/* ptrs to freed SVs now legal */
 PERLVAR(I, nomemok,	bool)		/* let malloc context handle nomem */
 PERLVARI(I, savebegin,	bool,	FALSE)	/* save BEGINs for compiler	*/
 
+
 PERLVAR(I, delaymagic_uid,	Uid_t)	/* current real user id, only for delaymagic */
 PERLVAR(I, delaymagic_euid,	Uid_t)	/* current effective user id, only for delaymagic */
 PERLVAR(I, delaymagic_gid,	Gid_t)	/* current real group id, only for delaymagic */
@@ -495,31 +515,10 @@ PERLVAR(I, sighandlerp,	Sighandler_t)
 
 PERLVARA(I, body_roots,	PERL_ARENA_ROOTS_SIZE, void*) /* array of body roots */
 
-PERLVAR(I, unicode, U32)	/* Unicode features: $ENV{PERL_UNICODE} or -C */
-
 PERLVARI(I, maxo,	int,	MAXO)	/* maximum number of ops */
 
 PERLVARI(I, runops,	runops_proc_t, RUNOPS_DEFAULT)
 
-/*
-=for apidoc Amn|SV|PL_sv_undef
-This is the C<undef> SV.  Always refer to this as C<&PL_sv_undef>.
-
-=for apidoc Amn|SV|PL_sv_no
-This is the C<false> SV.  See C<PL_sv_yes>.  Always refer to this as
-C<&PL_sv_no>.
-
-=for apidoc Amn|SV|PL_sv_yes
-This is the C<true> SV.  See C<PL_sv_no>.  Always refer to this as
-C<&PL_sv_yes>.
-
-=cut
-*/
-
-PERLVAR(I, sv_undef,	SV)
-PERLVAR(I, sv_no,	SV)
-PERLVAR(I, sv_yes,	SV)
-
 PERLVAR(I, subname,	SV *)		/* name of current subroutine */
 
 PERLVAR(I, subline,	I32)		/* line this subroutine began on */
@@ -546,15 +545,14 @@ PERLVARI(I, collation_standard, bool, TRUE)
 					/* Assume simple collation */
 #endif /* USE_LOCALE_COLLATE */
 
-
-#if defined (PERL_UTF8_CACHE_ASSERT) || defined (DEBUGGING)
-#  define PERL___I -1
-#else
-#  define PERL___I 1
+#ifdef PERL_SAWAMPERSAND
+PERLVAR(I, sawampersand, U8)		/* must save all match strings */
 #endif
-PERLVARI(I, utf8cache, I8, PERL___I)	/* Is the utf8 caching code enabled? */
-#undef PERL___I
 
+PERLVAR(I, unsafe,	bool)
+PERLVAR(I, colorset,	bool)		/* from regcomp.c */
+
+/* SPARE 2/3 bytes depending on PERL_SAWAMPERSAND */
 
 #ifdef USE_LOCALE_NUMERIC
 
@@ -605,7 +603,13 @@ PERLVAR(I, pad_reset_pending, bool)	/* reset pad on next attempted alloc */
 PERLVAR(I, srand_called, bool)
 PERLVARI(I, in_load_module, bool, FALSE)	/* to prevent recursions in PerlIO_find_layer */
 
-PERLVAR(I, parser,	yy_parser *)	/* current parser state */
+/* This value may be set when embedding for full cleanup  */
+/* 0=none, 1=full, 2=full with checks */
+/* mod_perl is special, and also assigns a meaning -1 */
+PERLVARI(I, perl_destruct_level, signed char,	0)
+
+/* current phase the interpreter is in */
+PERLVARI(I, phase,	enum perl_phase, PERL_PHASE_CONSTRUCT)
 
 /* Array of signal handlers, indexed by signal number, through which the C
    signal handler dispatches.  */
@@ -661,8 +665,6 @@ PERLVARI(I, def_layerlist, PerlIO_list_t *, NULL)
 
 PERLVARI(I, encoding,	SV *,	NULL)	/* character encoding */
 
-PERLVAR(I, debug_pad,	struct perl_debug_pad)	/* always needed because of the re extension */
-
 PERLVAR(I, utf8_idstart, SV *)
 PERLVAR(I, utf8_idcont,	SV *)
 PERLVAR(I, utf8_xidstart, SV *)
@@ -678,8 +680,6 @@ PERLVARI(I, unitcheckav_save, AV *, NULL)
 
 PERLVARI(I, clocktick,	long,	0)	/* this many times() ticks in a second */
 
-PERLVAR(I, stashcache,	HV *)		/* Cache to speed up S_method_common */
-
 /* Hooks to shared SVs and locks. */
 PERLVARI(I, sharehook,	share_proc_t, Perl_sv_nosharing)
 PERLVARI(I, lockhook,	share_proc_t, Perl_sv_nosharing)
@@ -721,6 +721,14 @@ PERLVARI(I, utf8_foldable, SV *, NULL)
 
 PERLVAR(I, custom_ops,	HV *)		/* custom op registrations */
 
+PERLVAR(I, Xpv,		XPV *)		/* (unused) held temporary value */
+
+/* name of the scopes we've ENTERed. Only used with -DDEBUGGING, but needs to be
+   present always, as -DDEBUGGING must be binary compatible with non.  */
+PERLVARI(I, scopestack_name, const char * *, NULL)
+
+PERLVAR(I, debug_pad,	struct perl_debug_pad)	/* always needed because of the re extension */
+
 /* Hook for File::Glob */
 PERLVARI(I, globhook,	globhook_t, NULL)