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pp_hot.c
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/* pp_hot.c
*
* Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
* 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 by Larry Wall and others
*
* You may distribute under the terms of either the GNU General Public
* License or the Artistic License, as specified in the README file.
*
*/
/*
* Then he heard Merry change the note, and up went the Horn-cry of Buckland,
* shaking the air.
*
* Awake! Awake! Fear, Fire, Foes! Awake!
* Fire, Foes! Awake!
*
* [p.1007 of _The Lord of the Rings_, VI/viii: "The Scouring of the Shire"]
*/
/* This file contains 'hot' pp ("push/pop") functions that
* execute the opcodes that make up a perl program. A typical pp function
* expects to find its arguments on the stack, and usually pushes its
* results onto the stack, hence the 'pp' terminology. Each OP structure
* contains a pointer to the relevant pp_foo() function.
*
* By 'hot', we mean common ops whose execution speed is critical.
* By gathering them together into a single file, we encourage
* CPU cache hits on hot code. Also it could be taken as a warning not to
* change any code in this file unless you're sure it won't affect
* performance.
*/
#include "EXTERN.h"
#define PERL_IN_PP_HOT_C
#include "perl.h"
#include "regcomp.h"
#include "feature.h"
/* Hot code. */
#ifdef PERL_RC_STACK
/* common code for pp_wrap() and xs_wrap():
* free any original arguments, and bump and shift down any return
* args
*/
STATIC void
S_pp_xs_wrap_return(pTHX_ I32 nargs, I32 old_sp)
{
I32 nret = (I32)(PL_stack_sp - PL_stack_base) - old_sp;
assert(nret >= 0);
/* bump any returned values */
if (nret) {
SV **svp = PL_stack_sp - nret + 1;
while (svp <= PL_stack_sp) {
SvREFCNT_inc(*svp);
svp++;
}
}
PL_curstackinfo->si_stack_nonrc_base = 0;
/* free the original args and shift the returned valued down */
if (nargs) {
SV **svp = PL_stack_sp - nret;
I32 i = nargs;
while (i--) {
SvREFCNT_dec(*svp);
*svp = NULL;
svp--;
}
if (nret) {
Move(PL_stack_sp - nret + 1,
PL_stack_sp - nret - nargs + 1,
nret, SV*);
}
PL_stack_sp -= nargs;
}
}
/* pp_wrap():
* wrapper function for pp() functions to turn them into functions
* that can operate on a reference-counted stack, by taking a non-
* reference-counted copy of the current stack frame, calling the real
* pp() function, then incrementing the reference count of any returned
* args.
*
* nargs or nlists indicate the number of stack arguments or the
* number of stack lists (delimited by MARKs) which the function expects.
*/
OP*
Perl_pp_wrap(pTHX_ Perl_ppaddr_t real_pp_fn, I32 nargs, int nlists)
{
PERL_ARGS_ASSERT_PP_WRAP;
if (!rpp_stack_is_rc())
/* stack-already non-RC; nothing needing wrapping */
return real_pp_fn(aTHX);
OP *next_op;
I32 old_sp = (I32)(PL_stack_sp - PL_stack_base);
assert(nargs >= 0);
assert(nlists >= 0);
assert(AvREAL(PL_curstack));
PL_curstackinfo->si_stack_nonrc_base = PL_stack_sp - PL_stack_base + 1;
if (nlists) {
assert(nargs == 0);
I32 mark = PL_markstack_ptr[-nlists+1];
nargs = (PL_stack_sp - PL_stack_base) - mark;
assert(nlists <= 2); /* if ever more, make below a loop */
PL_markstack_ptr[0] += nargs;
if (nlists == 2)
PL_markstack_ptr[-1] += nargs;
}
if (nargs) {
/* duplicate all the arg pointers further up the stack */
rpp_extend(nargs);
Copy(PL_stack_sp - nargs + 1, PL_stack_sp + 1, nargs, SV*);
PL_stack_sp += nargs;
}
next_op = real_pp_fn(aTHX);
/* we should still be a split stack */
assert(AvREAL(PL_curstack));
assert(PL_curstackinfo->si_stack_nonrc_base);
S_pp_xs_wrap_return(aTHX_ nargs, old_sp);
return next_op;
}
/* xs_wrap():
* similar in concept to pp_wrap: make a non-referenced-counted copy of
* a (not refcount aware) XS sub's args, call the XS subs, then bump any
* return values and free the original args */
void
Perl_xs_wrap(pTHX_ XSUBADDR_t xsub, CV *cv)
{
PERL_ARGS_ASSERT_XS_WRAP;
I32 old_sp = (I32)(PL_stack_sp - PL_stack_base);
I32 mark = PL_markstack_ptr[0];
I32 nargs = (PL_stack_sp - PL_stack_base) - mark;
/* we should be a fully refcounted stack */
assert(AvREAL(PL_curstack));
assert(!PL_curstackinfo->si_stack_nonrc_base);
PL_curstackinfo->si_stack_nonrc_base = PL_stack_sp - PL_stack_base + 1;
if (nargs) {
/* duplicate all the arg pointers further up the stack */
rpp_extend(nargs);
Copy(PL_stack_sp - nargs + 1, PL_stack_sp + 1, nargs, SV*);
PL_stack_sp += nargs;
PL_markstack_ptr[0] += nargs;
}
xsub(aTHX_ cv);
S_pp_xs_wrap_return(aTHX_ nargs, old_sp);
}
#endif
/* Private helper function for Perl_rpp_replace_2_1_COMMON()
* and rpp_popfree_2_NN().
* Free the two passed SVs, whose original ref counts are rc1 and rc2.
* Assumes the stack initially looked like
* .... sv1 sv2
* and is now:
* .... X
* but where sv2 is still on the slot above the current PL_stack_sp.
*/
void
Perl_rpp_free_2_(pTHX_ SV *const sv1, SV *const sv2,
const U32 rc1, const U32 rc2)
{
PERL_ARGS_ASSERT_RPP_FREE_2_;
#ifdef PERL_RC_STACK
if (rc1 > 1)
SvREFCNT(sv1) = rc1 - 1;
else {
/* temporarily reclaim sv2 on stack in case we die while freeing sv1 */
assert(PL_stack_sp[1] == sv2);
PL_stack_sp++;
Perl_sv_free2(aTHX_ sv1, rc1);
PL_stack_sp--;
}
if (rc2 > 1)
SvREFCNT(sv2) = rc2 - 1;
else
Perl_sv_free2(aTHX_ sv2, rc2);
#else
PERL_UNUSED_VAR(sv1);
PERL_UNUSED_VAR(sv2);
PERL_UNUSED_VAR(rc1);
PERL_UNUSED_VAR(rc2);
#endif
}
/* ----------------------------------------------------------- */
PP(pp_const)
{
rpp_xpush_1(cSVOP_sv);
return NORMAL;
}
PP(pp_nextstate)
{
PL_curcop = (COP*)PL_op;
TAINT_NOT; /* Each statement is presumed innocent */
rpp_popfree_to_NN(PL_stack_base + CX_CUR()->blk_oldsp);
FREETMPS;
PERL_ASYNC_CHECK();
return NORMAL;
}
PP(pp_gvsv)
{
assert(SvTYPE(cGVOP_gv) == SVt_PVGV);
rpp_xpush_1(
UNLIKELY(PL_op->op_private & OPpLVAL_INTRO)
? save_scalar(cGVOP_gv)
: GvSVn(cGVOP_gv));
return NORMAL;
}
/* also used for: pp_lineseq() pp_regcmaybe() pp_scalar() pp_scope() */
PP(pp_null)
{
return NORMAL;
}
/* This is sometimes called directly by pp_coreargs, pp_grepstart and
amagic_call. */
PP(pp_pushmark)
{
PUSHMARK(PL_stack_sp);
return NORMAL;
}
PP(pp_stringify)
{
dTARGET;
sv_copypv(TARG, *PL_stack_sp);
SvSETMAGIC(TARG);
rpp_replace_1_1_NN(TARG);
return NORMAL;
}
PP(pp_gv)
{
/* cGVOP_gv might be a real GV or might be an RV to a CV */
assert(SvTYPE(cGVOP_gv) == SVt_PVGV ||
(SvTYPE(cGVOP_gv) <= SVt_PVMG && SvROK(cGVOP_gv) && SvTYPE(SvRV(cGVOP_gv)) == SVt_PVCV));
rpp_xpush_1(MUTABLE_SV(cGVOP_gv));
return NORMAL;
}
/* also used for: pp_andassign() */
PP(pp_and)
{
PERL_ASYNC_CHECK();
{
SV * const sv = *PL_stack_sp;
if (!SvTRUE_NN(sv))
return NORMAL;
else {
if (PL_op->op_type == OP_AND)
rpp_popfree_1_NN();
return cLOGOP->op_other;
}
}
}
/*
* Mashup of simple padsv + sassign OPs
* Doesn't support the following lengthy and unlikely sassign case:
* (UNLIKELY(PL_op->op_private & OPpASSIGN_CV_TO_GV))
* These cases have a separate optimization, so are not handled here:
* (PL_op->op_private & OPpASSIGN_BACKWARDS) {or,and,dor}assign
*/
PP(pp_padsv_store)
{
OP * const op = PL_op;
SV** const padentry = &PAD_SVl(op->op_targ);
SV* targ = *padentry; /* lvalue to assign into */
SV* const val = *PL_stack_sp; /* RHS value to assign */
/* !OPf_STACKED is not handled by this OP */
assert(op->op_flags & OPf_STACKED);
/* Inlined, simplified pp_padsv here */
if ((op->op_private & (OPpLVAL_INTRO|OPpPAD_STATE)) == OPpLVAL_INTRO) {
save_clearsv(padentry);
}
/* Inlined, simplified pp_sassign from here */
assert(TAINTING_get || !TAINT_get);
if (UNLIKELY(TAINT_get) && !SvTAINTED(val))
TAINT_NOT;
if (
UNLIKELY(SvTEMP(targ)) && !SvSMAGICAL(targ) && SvREFCNT(targ) == 1 &&
(!isGV_with_GP(targ) || SvFAKE(targ)) && ckWARN(WARN_MISC)
)
Perl_warner(aTHX_
packWARN(WARN_MISC), "Useless assignment to a temporary"
);
SvSetMagicSV(targ, val);
rpp_replace_1_1_NN(targ);
return NORMAL;
}
/* A mashup of simplified AELEMFAST_LEX + SASSIGN OPs */
PP(pp_aelemfastlex_store)
{
OP * const op = PL_op;
SV* const val = *PL_stack_sp; /* RHS value to assign */
AV * const av = MUTABLE_AV(PAD_SV(op->op_targ));
const I8 key = (I8)PL_op->op_private;
SV * targ = NULL;
/* !OPf_STACKED is not handled by this OP */
assert(op->op_flags & OPf_STACKED);
/* Inlined, simplified pp_aelemfast here */
assert(SvTYPE(av) == SVt_PVAV);
/* inlined av_fetch() for simple cases ... */
if (!SvRMAGICAL(av) && key >=0 && key <= AvFILLp(av)) {
targ = AvARRAY(av)[key];
}
/* ... else do it the hard way */
if (!targ) {
SV **svp = av_fetch(av, key, 1);
if (svp)
targ = *svp;
else
DIE(aTHX_ PL_no_aelem, (int)key);
}
/* Inlined, simplified pp_sassign from here */
assert(TAINTING_get || !TAINT_get);
if (UNLIKELY(TAINT_get) && !SvTAINTED(val))
TAINT_NOT;
/* This assertion is a deviation from pp_sassign, which uses an if()
* condition to check for "Useless assignment to a temporary" and
* warns if the condition is true. Here, the condition should NEVER
* be true when the LHS is the result of an array fetch. The
* assertion is here as a final check that this remains the case.
*/
assert(!(SvTEMP(targ) && SvREFCNT(targ) == 1 && !SvSMAGICAL(targ)));
SvSetMagicSV(targ, val);
assert(GIMME_V == G_VOID);
rpp_popfree_1_NN();
return NORMAL;
}
PP(pp_sassign)
{
/* sassign keeps its args in the optree traditionally backwards.
So we pop them differently.
*/
SV *left = PL_stack_sp[0];
SV *right = PL_stack_sp[-1];
if (PL_op->op_private & OPpASSIGN_BACKWARDS) { /* {or,and,dor}assign */
SV * const temp = left;
left = right; right = temp;
PL_stack_sp[0] = left;
PL_stack_sp[-1] = right;
}
assert(TAINTING_get || !TAINT_get);
if (UNLIKELY(TAINT_get) && !SvTAINTED(right))
TAINT_NOT;
if (UNLIKELY(PL_op->op_private & OPpASSIGN_CV_TO_GV)) {
/* *foo =\&bar */
SV * const cv = SvRV(right);
const U32 cv_type = SvTYPE(cv);
const bool is_gv = isGV_with_GP(left);
const bool got_coderef = cv_type == SVt_PVCV || cv_type == SVt_PVFM;
if (!got_coderef) {
assert(SvROK(cv));
}
/* Can do the optimisation if left (LVALUE) is not a typeglob,
right (RVALUE) is a reference to something, and we're in void
context. */
if (!got_coderef && !is_gv && GIMME_V == G_VOID) {
/* Is the target symbol table currently empty? */
GV * const gv = gv_fetchsv_nomg(left, GV_NOINIT, SVt_PVGV);
if (SvTYPE(gv) != SVt_PVGV && !SvOK(gv)) {
/* Good. Create a new proxy constant subroutine in the target.
The gv becomes a(nother) reference to the constant. */
SV *const value = SvRV(cv);
SvUPGRADE(MUTABLE_SV(gv), SVt_IV);
SvPCS_IMPORTED_on(gv);
SvRV_set(gv, value);
SvREFCNT_inc_simple_void(value);
rpp_replace_2_1_NN(left);
return NORMAL;
}
}
/* Need to fix things up. */
if (!is_gv) {
/* Need to fix GV. */
SV *sv = MUTABLE_SV(gv_fetchsv_nomg(left,GV_ADD, SVt_PVGV));
rpp_replace_1_1_NN(sv);
left = sv;
}
if (!got_coderef) {
/* We've been returned a constant rather than a full subroutine,
but they expect a subroutine reference to apply. */
if (SvROK(cv)) {
ENTER_with_name("sassign_coderef");
SvREFCNT_inc_void(SvRV(cv));
/* newCONSTSUB takes a reference count on the passed in SV
from us. We set the name to NULL, otherwise we get into
all sorts of fun as the reference to our new sub is
donated to the GV that we're about to assign to.
*/
SvRV_set(right, MUTABLE_SV(newCONSTSUB(GvSTASH(left), NULL,
SvRV(cv))));
SvREFCNT_dec_NN(cv);
LEAVE_with_name("sassign_coderef");
} else {
/* What can happen for the corner case *{"BONK"} = \&{"BONK"};
is that
First: ops for \&{"BONK"}; return us the constant in the
symbol table
Second: ops for *{"BONK"} cause that symbol table entry
(and our reference to it) to be upgraded from RV
to typeblob)
Thirdly: We get here. cv is actually PVGV now, and its
GvCV() is actually the subroutine we're looking for
So change the reference so that it points to the subroutine
of that typeglob, as that's what they were after all along.
*/
GV *const upgraded = MUTABLE_GV(cv);
CV *const source = GvCV(upgraded);
assert(source);
assert(CvFLAGS(source) & CVf_CONST);
SvREFCNT_inc_simple_void_NN(source);
SvREFCNT_dec_NN(upgraded);
SvRV_set(right, MUTABLE_SV(source));
}
}
}
if (
rpp_is_lone(left) && !SvSMAGICAL(left) &&
(!isGV_with_GP(left) || SvFAKE(left)) && ckWARN(WARN_MISC)
)
Perl_warner(aTHX_
packWARN(WARN_MISC), "Useless assignment to a temporary"
);
SvSetMagicSV(left, right);
if (LIKELY(GIMME_V == G_VOID))
rpp_popfree_2_NN(); /* pop left and right */
else {
/* pop right, leave left on the stack */
assert(PL_stack_sp[-1] == right);
assert(PL_stack_sp[0] == left);
*--PL_stack_sp = left;
#ifdef PERL_RC_STACK
SvREFCNT_dec_NN(right);
#endif
}
return NORMAL;
}
PP(pp_cond_expr)
{
PERL_ASYNC_CHECK();
bool ok = SvTRUE_NN(*PL_stack_sp);
rpp_popfree_1_NN();
return (ok ? cLOGOP->op_other : cLOGOP->op_next);
}
PP(pp_unstack)
{
PERL_CONTEXT *cx;
PERL_ASYNC_CHECK();
TAINT_NOT; /* Each statement is presumed innocent */
cx = CX_CUR();
rpp_popfree_to_NN(PL_stack_base + CX_CUR()->blk_oldsp);
FREETMPS;
if (!(PL_op->op_flags & OPf_SPECIAL)) {
assert(CxTYPE(cx) == CXt_BLOCK || CxTYPE_is_LOOP(cx));
CX_LEAVE_SCOPE(cx);
}
return NORMAL;
}
/* The main body of pp_concat, not including the magic/overload and
* stack handling.
* It does targ = left . right.
* Moved into a separate function so that pp_multiconcat() can use it
* too.
*/
PERL_STATIC_INLINE void
S_do_concat(pTHX_ SV *left, SV *right, SV *targ, U8 targmy)
{
bool lbyte;
STRLEN rlen;
const char *rpv = NULL;
bool rbyte = FALSE;
bool rcopied = FALSE;
if (TARG == right && right != left) { /* $r = $l.$r */
rpv = SvPV_nomg_const(right, rlen);
rbyte = !DO_UTF8(right);
right = newSVpvn_flags(rpv, rlen, SVs_TEMP);
rpv = SvPV_const(right, rlen); /* no point setting UTF-8 here */
rcopied = TRUE;
}
if (TARG != left) { /* not $l .= $r */
STRLEN llen;
const char* const lpv = SvPV_nomg_const(left, llen);
lbyte = !DO_UTF8(left);
sv_setpvn(TARG, lpv, llen);
if (!lbyte)
SvUTF8_on(TARG);
else
SvUTF8_off(TARG);
}
else { /* $l .= $r and left == TARG */
if (!SvOK(left)) {
if ((left == right /* $l .= $l */
|| targmy) /* $l = $l . $r */
&& ckWARN(WARN_UNINITIALIZED)
)
report_uninit(left);
SvPVCLEAR(left);
}
else {
SvPV_force_nomg_nolen(left);
}
lbyte = !DO_UTF8(left);
if (IN_BYTES)
SvUTF8_off(left);
}
if (!rcopied) {
rpv = SvPV_nomg_const(right, rlen);
rbyte = !DO_UTF8(right);
}
if (lbyte != rbyte) {
if (lbyte)
sv_utf8_upgrade_nomg(TARG);
else {
if (!rcopied)
right = newSVpvn_flags(rpv, rlen, SVs_TEMP);
sv_utf8_upgrade_nomg(right);
rpv = SvPV_nomg_const(right, rlen);
}
}
sv_catpvn_nomg(TARG, rpv, rlen);
SvSETMAGIC(TARG);
}
PP(pp_concat)
{
SV *targ = (PL_op->op_flags & OPf_STACKED)
? PL_stack_sp[-1]
: PAD_SV(PL_op->op_targ);
if (rpp_try_AMAGIC_2(concat_amg, AMGf_assign))
return NORMAL;
SV *right = PL_stack_sp[0];
SV *left = PL_stack_sp[-1];
S_do_concat(aTHX_ left, right, targ, PL_op->op_private & OPpTARGET_MY);
rpp_replace_2_1_NN(targ);
return NORMAL;
}
/* pp_multiconcat()
Concatenate one or more args, possibly interleaved with constant string
segments. The result may be assigned to, or appended to, a variable or
expression.
Several op_flags and/or op_private bits indicate what the target is, and
whether it's appended to. Valid permutations are:
- (PADTMP) = (A.B.C....)
OPpTARGET_MY $lex = (A.B.C....)
OPpTARGET_MY,OPpLVAL_INTRO my $lex = (A.B.C....)
OPpTARGET_MY,OPpMULTICONCAT_APPEND $lex .= (A.B.C....)
OPf_STACKED expr = (A.B.C....)
OPf_STACKED,OPpMULTICONCAT_APPEND expr .= (A.B.C....)
Other combinations like (A.B).(C.D) are not optimised into a multiconcat
op, as it's too hard to get the correct ordering of ties, overload etc.
In addition:
OPpMULTICONCAT_FAKE: not a real concat, instead an optimised
sprintf "...%s...". Don't call '.'
overloading: only use '""' overloading.
OPpMULTICONCAT_STRINGIFY: the RHS was of the form
"...$a...$b..." rather than
"..." . $a . "..." . $b . "..."
An OP_MULTICONCAT is of type UNOP_AUX. The fixed slots of the aux array are
defined with PERL_MULTICONCAT_IX_FOO constants, where:
FOO index description
-------- ----- ----------------------------------
NARGS 0 number of arguments
PLAIN_PV 1 non-utf8 constant string
PLAIN_LEN 2 non-utf8 constant string length
UTF8_PV 3 utf8 constant string
UTF8_LEN 4 utf8 constant string length
LENGTHS 5 first of nargs+1 const segment lengths
The idea is that a general string concatenation will have a fixed (known
at compile time) number of variable args, interspersed with constant
strings, e.g. "a=$a b=$b\n"
All the constant string segments "a=", " b=" and "\n" are stored as a
single string "a= b=\n", pointed to from the PLAIN_PV/UTF8_PV slot, along
with a series of segment lengths: e.g. 2,3,1. In the case where the
constant string is plain but has a different utf8 representation, both
variants are stored, and two sets of (nargs+1) segments lengths are stored
in the slots beginning at PERL_MULTICONCAT_IX_LENGTHS.
A segment length of -1 indicates that there is no constant string at that
point; this distinguishes between e.g. ($a . $b) and ($a . "" . $b), which
have differing overloading behaviour.
*/
PP(pp_multiconcat)
{
SV *targ; /* The SV to be assigned or appended to */
char *targ_pv; /* where within SvPVX(targ) we're writing to */
STRLEN targ_len; /* SvCUR(targ) */
SV **toparg; /* the highest arg position on the stack */
UNOP_AUX_item *aux; /* PL_op->op_aux buffer */
UNOP_AUX_item *const_lens; /* the segment length array part of aux */
const char *const_pv; /* the current segment of the const string buf */
SSize_t nargs; /* how many args were expected */
SSize_t stack_adj; /* how much to adjust PL_stack_sp on return */
STRLEN grow; /* final size of destination string (targ) */
UV targ_count; /* how many times targ has appeared on the RHS */
bool is_append; /* OPpMULTICONCAT_APPEND flag is set */
bool slow_concat; /* args too complex for quick concat */
U32 dst_utf8; /* the result will be utf8 (indicate this with
SVf_UTF8 in a U32, rather than using bool,
for ease of testing and setting) */
/* for each arg, holds the result of an SvPV() call */
struct multiconcat_svpv {
const char *pv;
SSize_t len;
}
*targ_chain, /* chain of slots where targ has appeared on RHS */
*svpv_p, /* ptr for looping through svpv_buf */
*svpv_base, /* first slot (may be greater than svpv_buf), */
*svpv_end, /* and slot after highest result so far, of: */
svpv_buf[PERL_MULTICONCAT_MAXARG]; /* buf for storing SvPV() results */
aux = cUNOP_AUXx(PL_op)->op_aux;
stack_adj = nargs = aux[PERL_MULTICONCAT_IX_NARGS].ssize;
is_append = cBOOL(PL_op->op_private & OPpMULTICONCAT_APPEND);
/* get targ from the stack or pad */
toparg = PL_stack_sp;
if (PL_op->op_flags & OPf_STACKED) {
stack_adj++;
if (is_append) {
/* for 'expr .= ...', expr is the bottom item on the stack */
targ = PL_stack_sp[-nargs];
}
else {
/* for 'expr = ...', expr is the top item on the stack */
targ = *PL_stack_sp;
toparg--;
}
}
else {
SV **svp = &(PAD_SVl(PL_op->op_targ));
targ = *svp;
if (PL_op->op_private & OPpLVAL_INTRO) {
assert(PL_op->op_private & OPpTARGET_MY);
save_clearsv(svp);
}
if (!nargs)
/* $lex .= "const" doesn't cause anything to be pushed */
rpp_extend(1);
}
grow = 1; /* allow for '\0' at minimum */
targ_count = 0;
targ_chain = NULL;
targ_len = 0;
svpv_end = svpv_buf;
/* only utf8 variants of the const strings? */
dst_utf8 = aux[PERL_MULTICONCAT_IX_PLAIN_PV].pv ? 0 : SVf_UTF8;
/* --------------------------------------------------------------
* Phase 1:
*
* stringify (i.e. SvPV()) every arg and store the resultant pv/len/utf8
* triplets in svpv_buf[]. Also increment 'grow' by the args' lengths.
*
* utf8 is indicated by storing a negative length.
*
* Where an arg is actually targ, the stringification is deferred:
* the length is set to 0, and the slot is added to targ_chain.
*
* If a magic, overloaded, or otherwise weird arg is found, which
* might have side effects when stringified, the loop is abandoned and
* we goto a code block where a more basic 'emulate calling
* pp_cpncat() on each arg in turn' is done.
*/
for (SV **svp = toparg - (nargs - 1); svp <= toparg; svp++, svpv_end++) {
U32 utf8;
STRLEN len;
SV *sv;
assert(svpv_end - svpv_buf < PERL_MULTICONCAT_MAXARG);
sv = *svp;
/* this if/else chain is arranged so that common/simple cases
* take few conditionals */
if (LIKELY((SvFLAGS(sv) & (SVs_GMG|SVf_ROK|SVf_POK)) == SVf_POK)) {
/* common case: sv is a simple non-magical PV */
if (targ == sv) {
/* targ appears on RHS.
* Delay storing PV pointer; instead, add slot to targ_chain
* so it can be populated later, after targ has been grown and
* we know its final SvPVX() address.
*/
targ_on_rhs:
svpv_end->len = 0; /* zerojng here means we can skip
updating later if targ_len == 0 */
svpv_end->pv = (char*)targ_chain;
targ_chain = svpv_end;
targ_count++;
continue;
}
len = SvCUR(sv);
svpv_end->pv = SvPVX(sv);
}
else if (UNLIKELY(SvFLAGS(sv) & (SVs_GMG|SVf_ROK)))
/* may have side effects: tie, overload etc.
* Abandon 'stringify everything first' and handle
* args in strict order. Note that already-stringified args
* will be reprocessed, which is safe because the each first
* stringification would have been idempotent.
*/
goto do_magical;
else if (SvNIOK(sv)) {
if (targ == sv)
goto targ_on_rhs;
/* stringify general valid scalar */
svpv_end->pv = sv_2pv_flags(sv, &len, 0);
}
else if (!SvOK(sv)) {
if (ckWARN(WARN_UNINITIALIZED))
/* an undef value in the presence of warnings may trigger
* side affects */
goto do_magical;
svpv_end->pv = "";
len = 0;
}
else
goto do_magical; /* something weird */
utf8 = (SvFLAGS(sv) & SVf_UTF8);
dst_utf8 |= utf8;
ASSUME(len < SSize_t_MAX);
svpv_end->len = utf8 ? -(SSize_t)len : (SSize_t)len;
grow += len;
}
/* --------------------------------------------------------------
* Phase 2:
*
* Stringify targ:
*
* if targ appears on the RHS or is appended to, force stringify it;
* otherwise set it to "". Then set targ_len.
*/
if (is_append) {
/* abandon quick route if using targ might have side effects */
if (UNLIKELY(SvFLAGS(targ) & (SVs_GMG|SVf_ROK)))
goto do_magical;
if (SvOK(targ)) {
U32 targ_utf8;
stringify_targ:
SvPV_force_nomg_nolen(targ);
targ_utf8 = SvFLAGS(targ) & SVf_UTF8;
if (UNLIKELY(dst_utf8 & ~targ_utf8)) {
if (LIKELY(!IN_BYTES))
sv_utf8_upgrade_nomg(targ);
}
else
dst_utf8 |= targ_utf8;
targ_len = SvCUR(targ);
grow += targ_len * (targ_count + is_append);
goto phase3;
}
else if (ckWARN(WARN_UNINITIALIZED))
/* warning might have side effects */
goto do_magical;
/* the undef targ will be silently SvPVCLEAR()ed below */
}
else if (UNLIKELY(SvTYPE(targ) >= SVt_REGEXP)) {
/* Assigning to some weird LHS type. Don't force the LHS to be an
* empty string; instead, do things 'long hand' by using the
* overload code path, which concats to a TEMP sv and does
* sv_catsv() calls rather than COPY()s. This ensures that even
* bizarre code like this doesn't break or crash:
* *F = *F . *F.
* (which makes the 'F' typeglob an alias to the
* '*main::F*main::F' typeglob).
*/
goto do_magical;
}
else if (targ_chain)
/* targ was found on RHS.
* Force stringify it, using the same code as the append branch
* above, except that we don't need the magic/overload/undef
* checks as these will already have been done in the phase 1
* loop.
*/
goto stringify_targ;
/* unrolled SvPVCLEAR() - mostly: no need to grow or set SvCUR() to 0;
* those will be done later. */
SV_CHECK_THINKFIRST_COW_DROP(targ);
SvUPGRADE(targ, SVt_PV);
SvFLAGS(targ) &= ~(SVf_OK|SVf_IVisUV|SVf_UTF8);
SvFLAGS(targ) |= (SVf_POK|SVp_POK|dst_utf8);
phase3:
/* --------------------------------------------------------------
* Phase 3:
*
* UTF-8 tweaks and grow targ:
*
* Now that we know the length and utf8-ness of both the targ and
* args, grow targ to the size needed to accumulate all the args, based
* on whether targ appears on the RHS, whether we're appending, and
* whether any non-utf8 args expand in size if converted to utf8.
*
* For the latter, if dst_utf8 we scan non-utf8 args looking for
* variant chars, and adjust the svpv->len value of those args to the
* utf8 size and negate it to flag them. At the same time we un-negate
* the lens of any utf8 args since after this phase we no longer care
* whether an arg is utf8 or not.
*
* Finally, initialise const_lens and const_pv based on utf8ness.
* Note that there are 3 permutations:
*
* * If the constant string is invariant whether utf8 or not (e.g. "abc"),
* then aux[PERL_MULTICONCAT_IX_PLAIN_PV/LEN] are the same as
* aux[PERL_MULTICONCAT_IX_UTF8_PV/LEN] and there is one set of
* segment lengths.
*
* * If the string is fully utf8, e.g. "\x{100}", then
* aux[PERL_MULTICONCAT_IX_PLAIN_PV/LEN] == (NULL,0) and there is
* one set of segment lengths.
*
* * If the string has different plain and utf8 representations
* (e.g. "\x80"), then aux[PERL_MULTICONCAT_IX_PLAIN_PV/LEN]]
* holds the plain rep, while aux[PERL_MULTICONCAT_IX_UTF8_PV/LEN]
* holds the utf8 rep, and there are 2 sets of segment lengths,
* with the utf8 set following after the plain set.
*
* On entry to this section the (pv,len) pairs in svpv_buf have the
* following meanings:
* (pv, len) a plain string
* (pv, -len) a utf8 string
* (NULL, 0) left-most targ \ linked together R-to-L
* (next, 0) other targ / in targ_chain
*/
/* turn off utf8 handling if 'use bytes' is in scope */
if (UNLIKELY(dst_utf8 && IN_BYTES)) {
dst_utf8 = 0;
SvUTF8_off(targ);
/* undo all the negative lengths which flag utf8-ness */
for (svpv_p = svpv_buf; svpv_p < svpv_end; svpv_p++) {
SSize_t len = svpv_p->len;
if (len < 0)
svpv_p->len = -len;
}
}
/* grow += total of lengths of constant string segments */
{
SSize_t len;
len = aux[dst_utf8 ? PERL_MULTICONCAT_IX_UTF8_LEN
: PERL_MULTICONCAT_IX_PLAIN_LEN].ssize;
slow_concat = cBOOL(len);
grow += len;
}
const_lens = aux + PERL_MULTICONCAT_IX_LENGTHS;
if (dst_utf8) {
const_pv = aux[PERL_MULTICONCAT_IX_UTF8_PV].pv;
if ( aux[PERL_MULTICONCAT_IX_PLAIN_PV].pv
&& const_pv != aux[PERL_MULTICONCAT_IX_PLAIN_PV].pv)
/* separate sets of lengths for plain and utf8 */
const_lens += nargs + 1;
/* If the result is utf8 but some of the args aren't,
* calculate how much extra growth is needed for all the chars
* which will expand to two utf8 bytes.
* Also, if the growth is non-zero, negate the length to indicate
* that this is a variant string. Conversely, un-negate the
* length on utf8 args (which was only needed to flag non-utf8
* args in this loop */
for (svpv_p = svpv_buf; svpv_p < svpv_end; svpv_p++) {
SSize_t len, extra;
len = svpv_p->len;
if (len <= 0) {
svpv_p->len = -len;
continue;
}
extra = variant_under_utf8_count((U8 *) svpv_p->pv,
(U8 *) svpv_p->pv + len);
if (UNLIKELY(extra)) {
grow += extra;
/* -ve len indicates special handling */
svpv_p->len = -(len + extra);
slow_concat = TRUE;
}
}
}
else