#include "regcomp.h"
#define FCALL *f
-#define SV_CHECK_THINKFIRST(sv) if (SvTHINKFIRST(sv)) sv_force_normal(sv)
+#ifdef PERL_COPY_ON_WRITE
+#define SV_COW_NEXT_SV(sv) INT2PTR(SV *,SvUVX(sv))
+/* This is a pessamistic view. Scalar must be purely a read-write PV to copy-
+ on-write. */
+#define CAN_COW_MASK (SVs_OBJECT|SVs_GMG|SVs_SMG|SVf_IOK|SVf_NOK|SVf_POK| \
+ SVf_ROK|SVp_IOK|SVp_NOK|SVp_POK|SVf_FAKE|SVf_OOK| \
+ SVf_BREAK|SVf_READONLY|SVf_AMAGIC)
+#define CAN_COW_FLAGS (SVp_POK|SVf_POK)
+#endif
/* ============================================================================
MAGIC* magic = NULL;
HV* stash = Nullhv;
- if (mt != SVt_PV && SvREADONLY(sv) && SvFAKE(sv)) {
- sv_force_normal(sv);
+ if (mt != SVt_PV && SvIsCOW(sv)) {
+ sv_force_normal_flags(sv, 0);
}
if (SvTYPE(sv) == mt)
Renew(s,newlen,char);
}
else {
- /* sv_force_normal_flags() must not try to unshare the new
- PVX we allocate below. AMS 20010713 */
- if (SvREADONLY(sv) && SvFAKE(sv)) {
- SvFAKE_off(sv);
- SvREADONLY_off(sv);
- }
New(703, s, newlen, char);
if (SvPVX(sv) && SvCUR(sv)) {
Move(SvPVX(sv), s, (newlen < SvCUR(sv)) ? newlen : SvCUR(sv), char);
void
Perl_sv_setiv(pTHX_ register SV *sv, IV i)
{
- SV_CHECK_THINKFIRST(sv);
+ SV_CHECK_THINKFIRST_COW_DROP(sv);
switch (SvTYPE(sv)) {
case SVt_NULL:
sv_upgrade(sv, SVt_IV);
void
Perl_sv_setnv(pTHX_ register SV *sv, NV num)
{
- SV_CHECK_THINKFIRST(sv);
+ SV_CHECK_THINKFIRST_COW_DROP(sv);
switch (SvTYPE(sv)) {
case SVt_NULL:
case SVt_IV:
return SvIV(tmpstr);
return PTR2IV(SvRV(sv));
}
- if (SvREADONLY(sv) && SvFAKE(sv)) {
- sv_force_normal(sv);
+ if (SvIsCOW(sv)) {
+ sv_force_normal_flags(sv, 0);
}
if (SvREADONLY(sv) && !SvOK(sv)) {
if (ckWARN(WARN_UNINITIALIZED))
return SvUV(tmpstr);
return PTR2UV(SvRV(sv));
}
- if (SvREADONLY(sv) && SvFAKE(sv)) {
- sv_force_normal(sv);
+ if (SvIsCOW(sv)) {
+ sv_force_normal_flags(sv, 0);
}
if (SvREADONLY(sv) && !SvOK(sv)) {
if (ckWARN(WARN_UNINITIALIZED))
return SvNV(tmpstr);
return PTR2NV(SvRV(sv));
}
- if (SvREADONLY(sv) && SvFAKE(sv)) {
- sv_force_normal(sv);
+ if (SvIsCOW(sv)) {
+ sv_force_normal_flags(sv, 0);
}
if (SvREADONLY(sv) && !SvOK(sv)) {
if (ckWARN(WARN_UNINITIALIZED))
if (SvUTF8(sv))
return SvCUR(sv);
- if (SvREADONLY(sv) && SvFAKE(sv)) {
- sv_force_normal(sv);
+ if (SvIsCOW(sv)) {
+ sv_force_normal_flags(sv, 0);
}
if (PL_encoding)
U8 *s;
STRLEN len;
- if (SvREADONLY(sv) && SvFAKE(sv))
- sv_force_normal(sv);
+ if (SvIsCOW(sv)) {
+ sv_force_normal_flags(sv, 0);
+ }
s = (U8 *) SvPV(sv, len);
if (!utf8_to_bytes(s, &len)) {
if (fail_ok)
if (sstr == dstr)
return;
- SV_CHECK_THINKFIRST(dstr);
+ SV_CHECK_THINKFIRST_COW_DROP(dstr);
if (!sstr)
sstr = &PL_sv_undef;
stype = SvTYPE(sstr);
}
}
else if (sflags & SVp_POK) {
+ bool isSwipe = 0;
/*
* Check to see if we can just swipe the string. If so, it's a
* has to be allocated and SvPVX(sstr) has to be freed.
*/
- if (SvTEMP(sstr) && /* slated for free anyway? */
- SvREFCNT(sstr) == 1 && /* and no other references to it? */
- !(sflags & SVf_OOK) && /* and not involved in OOK hack? */
- SvLEN(sstr) && /* and really is a string */
+ if (
+#ifdef PERL_COPY_ON_WRITE
+ (sflags & (SVf_FAKE | SVf_READONLY)) != (SVf_FAKE | SVf_READONLY)
+ &&
+#endif
+ !(isSwipe =
+ (sflags & SVs_TEMP) && /* slated for free anyway? */
+ !(sflags & SVf_OOK) && /* and not involved in OOK hack? */
+ SvREFCNT(sstr) == 1 && /* and no other references to it? */
+ SvLEN(sstr) && /* and really is a string */
/* and won't be needed again, potentially */
- !(PL_op && PL_op->op_type == OP_AASSIGN))
- {
+ !(PL_op && PL_op->op_type == OP_AASSIGN))
+#ifdef PERL_COPY_ON_WRITE
+ && !((sflags & CAN_COW_MASK) == CAN_COW_FLAGS
+ && SvTYPE(sstr) >= SVt_PVIV)
+#endif
+ ) {
+ /* Failed the swipe test, and it's not a shared hash key either.
+ Have to copy the string. */
+ STRLEN len = SvCUR(sstr);
+ SvGROW(dstr, len + 1); /* inlined from sv_setpvn */
+ Move(SvPVX(sstr),SvPVX(dstr),len,char);
+ SvCUR_set(dstr, len);
+ *SvEND(dstr) = '\0';
+ (void)SvPOK_only(dstr);
+ } else {
+ /* If PERL_COPY_ON_WRITE is not defined, then isSwipe will always
+ be true in here. */
+#ifdef PERL_COPY_ON_WRITE
+ /* Either it's a shared hash key, or it's suitable for
+ copy-on-write or we can swipe the string. */
+#ifdef DEBUG_COW
+ PerlIO_printf(PerlIO_stderr(),"sstr --> dstr\n");
+ Perl_sv_dump(sstr);
+ Perl_sv_dump(dstr);
+#endif
+ if (!isSwipe) {
+ /* I believe I should acquire a global SV mutex if
+ it's a COW sv (not a shared hash key) to stop
+ it going un copy-on-write.
+ If the source SV has gone un copy on write between up there
+ and down here, then (assert() that) it is of the correct
+ form to make it copy on write again */
+ if ((sflags & (SVf_FAKE | SVf_READONLY))
+ != (SVf_FAKE | SVf_READONLY)) {
+ SvREADONLY_on(sstr);
+ SvFAKE_on(sstr);
+ /* Make the source SV into a loop of 1.
+ (about to become 2) */
+ SV_COW_NEXT_SV(sstr) = sstr;
+ }
+ }
+#endif
+ /* Initial code is common. */
if (SvPVX(dstr)) { /* we know that dtype >= SVt_PV */
if (SvOOK(dstr)) {
SvFLAGS(dstr) &= ~SVf_OOK;
Safefree(SvPVX(dstr));
}
(void)SvPOK_only(dstr);
- SvPV_set(dstr, SvPVX(sstr));
- SvLEN_set(dstr, SvLEN(sstr));
- SvCUR_set(dstr, SvCUR(sstr));
-
- SvTEMP_off(dstr);
- (void)SvOK_off(sstr); /* NOTE: nukes most SvFLAGS on sstr */
- SvPV_set(sstr, Nullch);
- SvLEN_set(sstr, 0);
- SvCUR_set(sstr, 0);
- SvTEMP_off(sstr);
- }
- else { /* have to copy actual string */
- STRLEN len = SvCUR(sstr);
- SvGROW(dstr, len + 1); /* inlined from sv_setpvn */
- Move(SvPVX(sstr),SvPVX(dstr),len,char);
- SvCUR_set(dstr, len);
- *SvEND(dstr) = '\0';
- (void)SvPOK_only(dstr);
- }
+
+#ifdef PERL_COPY_ON_WRITE
+ if (!isSwipe) {
+ /* making another shared SV. */
+ STRLEN cur = SvCUR(sstr);
+ STRLEN len = SvLEN(sstr);
+ if (len) {
+ /* SvIsCOW_normal */
+ /* splice us in between source and next-after-source. */
+ SV_COW_NEXT_SV(dstr) = SV_COW_NEXT_SV(sstr);
+ SV_COW_NEXT_SV(sstr) = dstr;
+ SvPV_set(dstr, SvPVX(sstr));
+ } else {
+ /* SvIsCOW_shared_hash */
+ UV hash = SvUVX(sstr);
+#ifdef DEBUG_COW
+ PerlIO_printf(PerlIO_stderr(), "Sharing hash\n");
+#endif
+ SvPV_set(dstr,
+ sharepvn(SvPVX(sstr),
+ (sflags & SVf_UTF8?-cur:cur), hash));
+ SvUVX(dstr) = hash;
+ }
+ SvLEN(dstr) = len;
+ SvCUR(dstr) = cur;
+ SvREADONLY_on(dstr);
+ SvFAKE_on(dstr);
+ /* Relesase a global SV mutex. */
+ }
+ else
+#endif
+ { /* Passes the swipe test. */
+ SvPV_set(dstr, SvPVX(sstr));
+ SvLEN_set(dstr, SvLEN(sstr));
+ SvCUR_set(dstr, SvCUR(sstr));
+
+ SvTEMP_off(dstr);
+ (void)SvOK_off(sstr); /* NOTE: nukes most SvFLAGS on sstr */
+ SvPV_set(sstr, Nullch);
+ SvLEN_set(sstr, 0);
+ SvCUR_set(sstr, 0);
+ SvTEMP_off(sstr);
+ }
+ }
if (sflags & SVf_UTF8)
SvUTF8_on(dstr);
/*SUPPRESS 560*/
{
register char *dptr;
- SV_CHECK_THINKFIRST(sv);
+ SV_CHECK_THINKFIRST_COW_DROP(sv);
if (!ptr) {
(void)SvOK_off(sv);
return;
{
register STRLEN len;
- SV_CHECK_THINKFIRST(sv);
+ SV_CHECK_THINKFIRST_COW_DROP(sv);
if (!ptr) {
(void)SvOK_off(sv);
return;
void
Perl_sv_usepvn(pTHX_ register SV *sv, register char *ptr, register STRLEN len)
{
- SV_CHECK_THINKFIRST(sv);
+ SV_CHECK_THINKFIRST_COW_DROP(sv);
(void)SvUPGRADE(sv, SVt_PV);
if (!ptr) {
(void)SvOK_off(sv);
SvSETMAGIC(sv);
}
+#ifdef PERL_COPY_ON_WRITE
+/* Need to do this *after* making the SV normal, as we need the buffer
+ pointer to remain valid until after we've copied it. If we let go too early,
+ another thread could invalidate it by unsharing last of the same hash key
+ (which it can do by means other than releasing copy-on-write Svs)
+ or by changing the other copy-on-write SVs in the loop. */
+STATIC void
+S_sv_release_COW(pTHX_ register SV *sv, char *pvx, STRLEN cur, STRLEN len,
+ U32 hash, SV *after)
+{
+ if (len) { /* this SV was SvIsCOW_normal(sv) */
+ /* we need to find the SV pointing to us. */
+ SV *current = SV_COW_NEXT_SV(after);
+
+ if (current == sv) {
+ /* The SV we point to points back to us (there were only two of us
+ in the loop.)
+ Hence other SV is no longer copy on write either. */
+ SvFAKE_off(after);
+ SvREADONLY_off(after);
+ } else {
+ /* We need to follow the pointers around the loop. */
+ SV *next;
+ while ((next = SV_COW_NEXT_SV(current)) != sv) {
+ assert (next);
+ current = next;
+ /* don't loop forever if the structure is bust, and we have
+ a pointer into a closed loop. */
+ assert (current != after);
+ }
+ /* Make the SV before us point to the SV after us. */
+ SV_COW_NEXT_SV(current) = after;
+ }
+ } else {
+ unsharepvn(pvx, SvUTF8(sv) ? -(I32)cur : cur, hash);
+ }
+}
+
+int
+Perl_sv_release_IVX(pTHX_ register SV *sv)
+{
+ if (SvIsCOW(sv))
+ sv_force_normal_flags(sv, 0);
+ return SvOOK_off(sv);
+}
+#endif
/*
=for apidoc sv_force_normal_flags
Undo various types of fakery on an SV: if the PV is a shared string, make
a private copy; if we're a ref, stop refing; if we're a glob, downgrade to
-an xpvmg. The C<flags> parameter gets passed to C<sv_unref_flags()>
-when unrefing. C<sv_force_normal> calls this function with flags set to 0.
+an xpvmg; if we're a copy-on-write scalar, this is the on-write time when
+we do the copy, and is also used locally. If C<SV_COW_DROP_PV> is set
+then a copy-on-write scalar drops its PV buffer (if any) and becomes
+SvPOK_off rather than making a copy. (Used where this scalar is about to be
+set to some other value. In addtion, the C<flags> parameter gets passed to
+C<sv_unref_flags()> when unrefing. C<sv_force_normal> calls this function
+with flags set to 0.
=cut
*/
void
Perl_sv_force_normal_flags(pTHX_ register SV *sv, U32 flags)
{
+#ifdef PERL_COPY_ON_WRITE
+ if (SvREADONLY(sv)) {
+ /* At this point I believe I should acquire a global SV mutex. */
+ if (SvFAKE(sv)) {
+ char *pvx = SvPVX(sv);
+ STRLEN len = SvLEN(sv);
+ STRLEN cur = SvCUR(sv);
+ U32 hash = SvUVX(sv);
+ SV *next = SV_COW_NEXT_SV(sv); /* next COW sv in the loop. */
+#ifdef DEBUG_COW
+ PerlIO_printf(PerlIO_stderr(), "Force normal %ld\n", flags);
+ Perl_sv_dump(sv);
+#endif
+ SvFAKE_off(sv);
+ SvREADONLY_off(sv);
+ /* This SV doesn't own the buffer, so need to New() a new one: */
+ SvPVX(sv) = 0;
+ SvLEN(sv) = 0;
+ if (flags & SV_COW_DROP_PV) {
+ /* OK, so we don't need to copy our buffer. */
+ SvPOK_off(sv);
+ } else {
+ SvGROW(sv, cur + 1);
+ Move(pvx,SvPVX(sv),cur,char);
+ SvCUR(sv) = cur;
+ *SvEND(sv) = '\0';
+ }
+ S_sv_release_COW(sv, pvx, cur, len, hash, next);
+#ifdef DEBUG_COW
+ Perl_sv_dump(sv);
+#endif
+ }
+ else if (PL_curcop != &PL_compiling)
+ Perl_croak(aTHX_ PL_no_modify);
+ /* At this point I believe that I can drop the global SV mutex. */
+ }
+#else
if (SvREADONLY(sv)) {
if (SvFAKE(sv)) {
char *pvx = SvPVX(sv);
else if (PL_curcop != &PL_compiling)
Perl_croak(aTHX_ PL_no_modify);
}
+#endif
if (SvROK(sv))
sv_unref_flags(sv, flags);
else if (SvFAKE(sv) && SvTYPE(sv) == SVt_PVGV)
MAGIC* mg;
MGVTBL *vtable = 0;
+#ifdef PERL_COPY_ON_WRITE
+ if (SvIsCOW(sv))
+ sv_force_normal_flags(sv, 0);
+#endif
if (SvREADONLY(sv)) {
if (PL_curcop != &PL_compiling
&& how != PERL_MAGIC_regex_global
Perl_sv_replace(pTHX_ register SV *sv, register SV *nsv)
{
U32 refcnt = SvREFCNT(sv);
- SV_CHECK_THINKFIRST(sv);
+ SV_CHECK_THINKFIRST_COW_DROP(sv);
if (SvREFCNT(nsv) != 1 && ckWARN_d(WARN_INTERNAL))
Perl_warner(aTHX_ packWARN(WARN_INTERNAL), "Reference miscount in sv_replace()");
if (SvMAGICAL(sv)) {
else
SvREFCNT_dec(SvRV(sv));
}
+#ifdef PERL_COPY_ON_WRITE
+ else if (SvPVX(sv)) {
+ if (SvIsCOW(sv)) {
+ /* I believe I need to grab the global SV mutex here and
+ then recheck the COW status. */
+#ifdef DEBUG_COW
+ PerlIO_printf(PerlIO_stderr(), "Clear\n");
+ Perl_sv_dump(sv);
+#endif
+ S_sv_release_COW(sv, SvPVX(sv), SvCUR(sv), SvLEN(sv),
+ SvUVX(sv), SV_COW_NEXT_SV(sv));
+ /* And drop it here. */
+ SvFAKE_off(sv);
+ } else if (SvLEN(sv)) {
+ Safefree(SvPVX(sv));
+ }
+ }
+#else
else if (SvPVX(sv) && SvLEN(sv))
Safefree(SvPVX(sv));
else if (SvPVX(sv) && SvREADONLY(sv) && SvFAKE(sv)) {
SvUVX(sv));
SvFAKE_off(sv);
}
+#endif
break;
/*
case SVt_NV:
}
if (cur1 == cur2)
- eq = memEQ(pv1, pv2, cur1);
+ eq = (pv1 == pv2) || memEQ(pv1, pv2, cur1);
if (svrecode)
SvREFCNT_dec(svrecode);
I32 i = 0;
I32 rspara = 0;
- SV_CHECK_THINKFIRST(sv);
+ SV_CHECK_THINKFIRST_COW_DROP(sv);
+ /* XXX. If you make this PVIV, then copy on write can copy scalars read
+ from <>.
+ However, perlbench says it's slower, because the existing swipe code
+ is faster than copy on write.
+ Swings and roundabouts. */
(void)SvUPGRADE(sv, SVt_PV);
SvSCREAM_off(sv);
if (SvGMAGICAL(sv))
mg_get(sv);
if (SvTHINKFIRST(sv)) {
- if (SvREADONLY(sv) && SvFAKE(sv))
- sv_force_normal(sv);
+ if (SvIsCOW(sv))
+ sv_force_normal_flags(sv, 0);
if (SvREADONLY(sv)) {
if (PL_curcop != &PL_compiling)
Perl_croak(aTHX_ PL_no_modify);
if (SvGMAGICAL(sv))
mg_get(sv);
if (SvTHINKFIRST(sv)) {
- if (SvREADONLY(sv) && SvFAKE(sv))
- sv_force_normal(sv);
+ if (SvIsCOW(sv))
+ sv_force_normal_flags(sv, 0);
if (SvREADONLY(sv)) {
if (PL_curcop != &PL_compiling)
Perl_croak(aTHX_ PL_no_modify);
char *s = NULL;
if (SvTHINKFIRST(sv) && !SvROK(sv))
- sv_force_normal(sv);
+ sv_force_normal_flags(sv, 0);
if (SvPOK(sv)) {
*lp = SvCUR(sv);
new_SV(sv);
- SV_CHECK_THINKFIRST(rv);
+ SV_CHECK_THINKFIRST_COW_DROP(rv);
SvAMAGIC_off(rv);
if (SvTYPE(rv) >= SVt_PVMG) {
}
SvRV(sv) = 0;
SvROK_off(sv);
- if (SvREFCNT(rv) != 1 || SvREADONLY(rv) || flags) /* SV_IMMEDIATE_UNREF */
+ if (SvREFCNT(rv) != 1 || SvREADONLY(rv) || (flags & SV_IMMEDIATE_UNREF))
SvREFCNT_dec(rv);
else /* XXX Hack, but hard to make $a=$a->[1] work otherwise */
sv_2mortal(rv); /* Schedule for freeing later */
projects / p5sagit/p5-mst-13.2.git / commitdiff