Make newSV_type an inline function

When a new SV is created and upgraded to a type known at compile time,
uprooting a SV head and then using the general-purpose upgrade function
(sv_upgrade) is clunky. Specifically, while uprooting a SV head is
lightweight (assuming there are unused SVs), sv_upgrade is too big to be
inlined, contains many branches that can logically be resolved at compile
time for known start & end types, and the lookup of the correct
body_details struct may add CPU cycles.

This commit tries to address that by making newSV_type an inline function
and including only the parts of sv_upgrade needed to upgrade a SVt_NULL.
When the destination type is known at compile time, a decent compiler will
inline a call to newSV_type and use the type information to throw away all
the irrelevant parts of the sv_upgrade logic.

Because of the spread of type definitions across header files, it did not
seem possible to make the necessary changed inside sv.h, and so a new
header file (sv_inline.h) was created. For the inlined function to work
outside of sv.c, many definitions from that file were moved to sv_inline.h.

Finally, in order to also benefit from this change, existing code in sv.c
that does things like this:
    SV* sv;
    new_SV(sv);
    sv_upgrade(sv, SVt_PV)
has been modified to read something like:
    SV* sv = newSV_type(SVt_PV);

Author: richardleach

MANIFEST

@@ -5569,6 +5569,7 @@ scope.h				Scope entry and exit header
 SECURITY.md			Add Security Policy for GitHub
 sv.c				Scalar value code
 sv.h				Scalar value header
+sv_inline.h			Perl_newSV_type and required defs
 t/base/cond.t			See if conditionals work
 t/base/if.t			See if if works
 t/base/lex.t			See if lexical items work

embed.fnc

@@ -1519,7 +1519,7 @@ Apd	|SV*	|newSVrv	|NN SV *const rv|NULLOK const char *const classname
 ApMbdR	|SV*	|newSVsv	|NULLOK SV *const old
 AmdR	|SV*	|newSVsv_nomg	|NULLOK SV *const old
 AdpR	|SV*	|newSVsv_flags	|NULLOK SV *const old|I32 flags
-ApdR	|SV*	|newSV_type	|const svtype type
+ApdiR	|SV*	|newSV_type	|const svtype type
 ApdR	|OP*	|newUNOP	|I32 type|I32 flags|NULLOK OP* first
 ApdR	|OP*	|newUNOP_AUX	|I32 type|I32 flags|NULLOK OP* first \
 				|NULLOK UNOP_AUX_item *aux
@@ -3171,7 +3171,7 @@ S	|STRLEN	|sv_pos_b2u_midway|NN const U8 *const s|NN const U8 *const target \
 S	|void	|assert_uft8_cache_coherent|NN const char *const func \
 		|STRLEN from_cache|STRLEN real|NN SV *const sv
 ST	|char *	|F0convert	|NV nv|NN char *const endbuf|NN STRLEN *const len
-S	|SV *	|more_sv
+Cp	|SV *	|more_sv
 S	|bool	|sv_2iuv_common	|NN SV *const sv
 S	|void	|glob_assign_glob|NN SV *const dsv|NN SV *const ssv \
 		|const int dtype
@@ -3180,7 +3180,7 @@ S	|void	|anonymise_cv_maybe	|NN GV *gv|NN CV *cv
 #endif
 
 : Used in sv.c and hv.c
-po	|void *	|more_bodies	|const svtype sv_type|const size_t body_size \
+Cpo	|void *	|more_bodies	|const svtype sv_type|const size_t body_size \
 				|const size_t arena_size
 EXpR	|SV*	|get_and_check_backslash_N_name|NN const char* s	\
 				|NN const char* e			\

embed.h

@@ -881,6 +881,9 @@
 #define dump_mstats(a)		Perl_dump_mstats(aTHX_ a)
 #define get_mstats(a,b,c)	Perl_get_mstats(aTHX_ a,b,c)
 #endif
+#if defined(PERL_IN_SV_C)
+#define more_sv()		Perl_more_sv(aTHX)
+#endif
 #if defined(PERL_USE_3ARG_SIGHANDLER)
 #define csighandler		Perl_csighandler
 #endif
@@ -1932,7 +1935,6 @@
 #define find_uninit_var(a,b,c,d)	S_find_uninit_var(aTHX_ a,b,c,d)
 #define glob_2number(a)		S_glob_2number(aTHX_ a)
 #define glob_assign_glob(a,b,c)	S_glob_assign_glob(aTHX_ a,b,c)
-#define more_sv()		S_more_sv(aTHX)
 #define not_a_number(a)		S_not_a_number(aTHX_ a)
 #define not_incrementable(a)	S_not_incrementable(aTHX_ a)
 #define ptr_table_find		S_ptr_table_find

perl.h

@@ -1252,12 +1252,6 @@ Use L</UV> to declare variables of the maximum usable size on this platform.
           (((U64)(x) & UINT64_C(0xff00000000000000)) >> 56) ))
 # endif
 
-/* The old value was hard coded at 1008. (4096-16) seems to be a bit faster,
-   at least on FreeBSD.  YMMV, so experiment.  */
-#ifndef PERL_ARENA_SIZE
-#define PERL_ARENA_SIZE 4080
-#endif
-
 /* Maximum level of recursion */
 #ifndef PERL_SUB_DEPTH_WARN
 #define PERL_SUB_DEPTH_WARN 100
@@ -7160,6 +7154,7 @@ cannot have changed since the precalculation.
 START_EXTERN_C
 
 #  include "inline.h"
+#  include "sv_inline.h"
 
 END_EXTERN_C
 

proto.h

@@ -2482,9 +2482,11 @@ PERL_CALLCONV OP*	Perl_newSVREF(pTHX_ OP* o)
 #define PERL_ARGS_ASSERT_NEWSVREF	\
 	assert(o)
 
-PERL_CALLCONV SV*	Perl_newSV_type(pTHX_ const svtype type)
+#ifndef PERL_NO_INLINE_FUNCTIONS
+PERL_STATIC_INLINE SV*	Perl_newSV_type(pTHX_ const svtype type)
 			__attribute__warn_unused_result__;
 #define PERL_ARGS_ASSERT_NEWSV_TYPE
+#endif
 
 PERL_CALLCONV SV*	Perl_newSVavdefelem(pTHX_ AV *av, SSize_t ix, bool extendible)
 			__attribute__warn_unused_result__;
@@ -6461,7 +6463,7 @@ STATIC bool	S_glob_2number(pTHX_ GV* const gv);
 STATIC void	S_glob_assign_glob(pTHX_ SV *const dsv, SV *const ssv, const int dtype);
 #define PERL_ARGS_ASSERT_GLOB_ASSIGN_GLOB	\
 	assert(dsv); assert(ssv)
-STATIC SV *	S_more_sv(pTHX);
+PERL_CALLCONV SV *	Perl_more_sv(pTHX);
 #define PERL_ARGS_ASSERT_MORE_SV
 STATIC void	S_not_a_number(pTHX_ SV *const sv);
 #define PERL_ARGS_ASSERT_NOT_A_NUMBER	\