X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=sv.h;h=dd1350531379b104e978208734a23d6dd2b415c9;hb=ac09da3b9065d6e75850e3772d9b883653c64a70;hp=ba873ea5ee7dde10bb8459532b3ef00c4a153fbd;hpb=1fef4616ad97a72dc45194bd8ac11e63e518aba2;p=p5sagit%2Fp5-mst-13.2.git

diff --git a/sv.h b/sv.h
index ba873ea..dd13505 100644
--- a/sv.h
+++ b/sv.h
@@ -177,9 +177,8 @@ to return a meaningful value, or check for NULLness, so it's smaller
 and faster.
 
 =for apidoc Am|SV*|SvREFCNT_inc_simple|SV* sv
-Same as SvREFCNT_inc, but can only be used with simple variables, not
-expressions or pointer dereferences.  Since we don't have to store a
-temporary value, it's faster.
+Same as SvREFCNT_inc, but can only be used with expressions without side
+effects.  Since we don't have to store a temporary value, it's faster.
 
 =for apidoc Am|SV*|SvREFCNT_inc_simple_NN|SV* sv
 Same as SvREFCNT_inc_simple, but can only be used if you know I<sv>
@@ -345,15 +344,20 @@ perform the upgrade if necessary.  See C<svtype>.
 #define PRIVSHIFT 4	/* (SVp_?OK >> PRIVSHIFT) == SVf_?OK */
 
 #define SVf_AMAGIC	0x10000000  /* has magical overloaded methods */
+
+/* Ensure this value does not clash with the GV_ADD* flags in gv.h: */
 #define SVf_UTF8        0x20000000  /* SvPV is UTF-8 encoded
 				       This is also set on RVs whose overloaded
 				       stringification is UTF-8. This might
 				       only happen as a side effect of SvPV() */
 					   
-/* Ensure this value does not clash with the GV_ADD* flags in gv.h */
 
 /* Some private flags. */
 
+/* PVAV could probably use 0x2000000 without conflict. I assume that PVFM can
+   be UTF-8 encoded, and PVCVs could well have UTF-8 prototypes. PVIOs haven't
+   been restructured, so sometimes get used as string buffers.  */
+
 /* PVHV */
 #define SVphv_SHAREKEYS 0x20000000  /* PVHV keys live on shared string table */
 /* PVNV, PVMG, presumably only inside pads */
@@ -1215,9 +1219,7 @@ the scalar's value cannot change unless written to.
 	} STMT_END
 
 #ifdef PERL_DEBUG_COW
-#define SvRV(sv) (0 + (sv)->sv_u.svu_rv)
 #else
-#define SvRV(sv) ((sv)->sv_u.svu_rv)
 #endif
 #define SvRVx(sv) SvRV(sv)
 
@@ -1227,6 +1229,7 @@ the scalar's value cannot change unless written to.
 #  define SvIVX(sv) (0 + ((XPVIV*) SvANY(sv))->xiv_iv)
 #  define SvUVX(sv) (0 + ((XPVUV*) SvANY(sv))->xuv_uv)
 #  define SvNVX(sv) (-0.0 + ((XPVNV*) SvANY(sv))->xnv_u.xnv_nv)
+#  define SvRV(sv) (0 + (sv)->sv_u.svu_rv)
 /* Don't test the core XS code yet.  */
 #  if defined (PERL_CORE) && PERL_DEBUG_COW > 1
 #    define SvPVX(sv) (0 + (assert(!SvREADONLY(sv)), (sv)->sv_u.svu_pv))
@@ -1294,6 +1297,16 @@ the scalar's value cannot change unless written to.
 	    assert(!isGV_with_GP(_svi));				\
 	   &(((XPVNV*) SvANY(_svi))->xnv_u.xnv_nv);			\
 	 }))
+#    define SvRV(sv)							\
+	(*({ SV *const _svi = (SV *) (sv);				\
+	    assert(SvTYPE(_svi) >= SVt_RV);				\
+	    assert(SvTYPE(_svi) != SVt_PVAV);				\
+	    assert(SvTYPE(_svi) != SVt_PVHV);				\
+	    assert(SvTYPE(_svi) != SVt_PVCV);				\
+	    assert(SvTYPE(_svi) != SVt_PVFM);				\
+	    assert(!isGV_with_GP(_svi));				\
+	    &((_svi)->sv_u.svu_rv);					\
+	 }))
 #    define SvMAGIC(sv)							\
 	(*({ SV *const _svi = (SV *) (sv);				\
 	    assert(SvTYPE(_svi) >= SVt_PVMG);				\
@@ -1312,6 +1325,7 @@ the scalar's value cannot change unless written to.
 #    define SvIVX(sv) ((XPVIV*) SvANY(sv))->xiv_iv
 #    define SvUVX(sv) ((XPVUV*) SvANY(sv))->xuv_uv
 #    define SvNVX(sv) ((XPVNV*) SvANY(sv))->xnv_u.xnv_nv
+#    define SvRV(sv) ((sv)->sv_u.svu_rv)
 #    define SvMAGIC(sv)	((XPVMG*)  SvANY(sv))->xmg_u.xmg_magic
 #    define SvSTASH(sv)	((XPVMG*)  SvANY(sv))->xmg_stash
 #  endif
@@ -1371,6 +1385,10 @@ the scalar's value cannot change unless written to.
 		(((XPVUV*)SvANY(sv))->xuv_uv = (val)); } STMT_END
 #define SvRV_set(sv, val) \
         STMT_START { assert(SvTYPE(sv) >=  SVt_RV); \
+		assert(SvTYPE(sv) != SVt_PVAV);		\
+		assert(SvTYPE(sv) != SVt_PVHV);		\
+		assert(SvTYPE(sv) != SVt_PVCV);		\
+		assert(SvTYPE(sv) != SVt_PVFM);		\
 		assert(!isGV_with_GP(sv));		\
                 ((sv)->sv_u.svu_rv = (val)); } STMT_END
 #define SvMAGIC_set(sv, val) \
@@ -1550,7 +1568,9 @@ stringified version becoming C<SvPOK>.  Handles 'get' magic. See also
 C<SvPVx> for a version which guarantees to evaluate sv only once.
 
 =for apidoc Am|char*|SvPVx|SV* sv|STRLEN len
-A version of C<SvPV> which guarantees to evaluate sv only once.
+A version of C<SvPV> which guarantees to evaluate C<sv> only once.
+Only use this if C<sv> is an expression with side effects, otherwise use the
+more efficient C<SvPVX>.
 
 =for apidoc Am|char*|SvPV_nomg|SV* sv|STRLEN len
 Like C<SvPV> but doesn't process magic.
@@ -1569,7 +1589,8 @@ Like C<SvIV> but doesn't process magic.
 
 =for apidoc Am|IV|SvIVx|SV* sv
 Coerces the given SV to an integer and returns it. Guarantees to evaluate
-sv only once. Use the more efficient C<SvIV> otherwise.
+C<sv> only once. Only use this if C<sv> is an expression with side effects,
+otherwise use the more efficient C<SvIV>.
 
 =for apidoc Am|NV|SvNV|SV* sv
 Coerce the given SV to a double and return it. See C<SvNVx> for a version
@@ -1577,7 +1598,8 @@ which guarantees to evaluate sv only once.
 
 =for apidoc Am|NV|SvNVx|SV* sv
 Coerces the given SV to a double and returns it. Guarantees to evaluate
-sv only once. Use the more efficient C<SvNV> otherwise.
+C<sv> only once. Only use this if C<sv> is an expression with side effects,
+otherwise use the more efficient C<SvNV>.
 
 =for apidoc Am|UV|SvUV|SV* sv
 Coerces the given SV to an unsigned integer and returns it.  See C<SvUVx>
@@ -1588,7 +1610,8 @@ Like C<SvUV> but doesn't process magic.
 
 =for apidoc Am|UV|SvUVx|SV* sv
 Coerces the given SV to an unsigned integer and returns it. Guarantees to
-evaluate sv only once. Use the more efficient C<SvUV> otherwise.
+C<sv> only once. Only use this if C<sv> is an expression with side effects,
+otherwise use the more efficient C<SvUV>.
 
 =for apidoc Am|bool|SvTRUE|SV* sv
 Returns a boolean indicating whether Perl would evaluate the SV as true or
@@ -1835,13 +1858,15 @@ Like C<sv_catsv> but doesn't process magic.
 #define SV_SMAGIC		128
 #define SV_HAS_TRAILING_NUL	256
 #define SV_COW_SHARED_HASH_KEYS	512
+/* This one is only enabled for PERL_OLD_COPY_ON_WRITE */
+#define SV_COW_OTHER_PVS	1024
 
 /* The core is safe for this COW optimisation. XS code on CPAN may not be.
    So only default to doing the COW setup if we're in the core.
  */
 #ifdef PERL_CORE
 #  ifndef SV_DO_COW_SVSETSV
-#    define SV_DO_COW_SVSETSV	SV_COW_SHARED_HASH_KEYS
+#    define SV_DO_COW_SVSETSV	SV_COW_SHARED_HASH_KEYS|SV_COW_OTHER_PVS
 #  endif
 #endif