Hash lookup of constant strings optimization:

Introduce SvREADONLY && SvFAKE to flag an SV which has SvPVX pointing
to string table (as per sharepvn). Add newSV_pvn_share to create such
a thing. Make hv.c compare addresses of strings and skip string compare
if equal. Make method_named and helem ops use these shared-string SVs
when arg is constant. Make keys op return shared-string SVs (less clearly
a win).

p4raw-id: //depot/perl@7016

1 files changed, 23 insertions, 22 deletions

diff --git a/embed.pl b/embed.pl
index b99a59f3cd..c8e83f85ce 100755
--- a/embed.pl
+++ b/embed.pl
@@ -135,12 +135,12 @@ sub write_protos {
 	}
 	$ret .= ")";
 	$ret .= " __attribute__((noreturn))" if $flags =~ /r/;
-	if( $flags =~ /f/ ) { 
+	if( $flags =~ /f/ ) {
 	    my $prefix = $flags =~ /n/ ? '' : 'pTHX_';
-	    my $args = scalar @args; 
+	    my $args = scalar @args;
 	    $ret .= "\n#ifdef CHECK_FORMAT\n";
 	    $ret .= sprintf " __attribute__((format(printf,%s%d,%s%d)))",
-				    $prefix, $args - 1, $prefix, $args; 
+				    $prefix, $args - 1, $prefix, $args;
 	    $ret .= "\n#endif\n";
 	}
 	$ret .= ";\n";
@@ -185,11 +185,11 @@ EOT
 #       hints
 #       copline
 my @extvars = qw(sv_undef sv_yes sv_no na dowarn
-                 curcop compiling 
+                 curcop compiling
                  tainting tainted stack_base stack_sp sv_arenaroot
 		 no_modify
                  curstash DBsub DBsingle debstash
-                 rsfp 
+                 rsfp
                  stdingv
 		 defgv
 		 errgv
@@ -280,7 +280,7 @@ unlink 'embed.h';
 open(EM, '> embed.h') or die "Can't create embed.h: $!\n";
 
 print EM <<'END';
-/* !!!!!!!   DO NOT EDIT THIS FILE   !!!!!!! 
+/* !!!!!!!   DO NOT EDIT THIS FILE   !!!!!!!
    This file is built by embed.pl from data in embed.pl, pp.sym, intrpvar.h,
    perlvars.h and thrdvar.h.  Any changes made here will be lost!
 */
@@ -542,7 +542,7 @@ open(EM, '> embedvar.h')
     or die "Can't create embedvar.h: $!\n";
 
 print EM <<'END';
-/* !!!!!!!   DO NOT EDIT THIS FILE   !!!!!!! 
+/* !!!!!!!   DO NOT EDIT THIS FILE   !!!!!!!
    This file is built by embed.pl from data in embed.pl, pp.sym, intrpvar.h,
    perlvars.h and thrdvar.h.  Any changes made here will be lost!
 */
@@ -708,7 +708,7 @@ open(OBX, '> objXSUB.h')
     or die "Can't create objXSUB.h: $!\n";
 
 print OBX <<'EOT';
-/* !!!!!!!   DO NOT EDIT THIS FILE   !!!!!!! 
+/* !!!!!!!   DO NOT EDIT THIS FILE   !!!!!!!
    This file is built by embed.pl from data in embed.pl, pp.sym, intrpvar.h,
    perlvars.h and thrdvar.h.  Any changes made here will be lost!
 */
@@ -766,7 +766,7 @@ open(CAPI, '> perlapi.c') or die "Can't create perlapi.c: $!\n";
 open(CAPIH, '> perlapi.h') or die "Can't create perlapi.h: $!\n";
 
 print CAPIH <<'EOT';
-/* !!!!!!!   DO NOT EDIT THIS FILE   !!!!!!! 
+/* !!!!!!!   DO NOT EDIT THIS FILE   !!!!!!!
    This file is built by embed.pl from data in embed.pl, pp.sym, intrpvar.h,
    perlvars.h and thrdvar.h.  Any changes made here will be lost!
 */
@@ -873,7 +873,7 @@ EOT
 close CAPIH;
 
 print CAPI <<'EOT';
-/* !!!!!!!   DO NOT EDIT THIS FILE   !!!!!!! 
+/* !!!!!!!   DO NOT EDIT THIS FILE   !!!!!!!
    This file is built by embed.pl from data in embed.pl, pp.sym, intrpvar.h,
    perlvars.h and thrdvar.h.  Any changes made here will be lost!
 */
@@ -1132,7 +1132,7 @@ sub docout ($$$) { # output the docs for one function
 
     $docs .= "NOTE: this function is experimental and may change or be
 removed without notice.\n\n" if $flags =~ /x/;
-    $docs .= "NOTE: the perl_ form of this function is deprecated.\n\n" 
+    $docs .= "NOTE: the perl_ form of this function is deprecated.\n\n"
 	if $flags =~ /p/;
 
     print $fh "=item $name\n$docs";
@@ -1159,7 +1159,7 @@ for $file (glob('*.c'), glob('*.h')) {
 }
 
 unlink "pod/perlapi.pod";
-open (DOC, ">pod/perlapi.pod") or 
+open (DOC, ">pod/perlapi.pod") or
 	die "Can't create pod/perlapi.pod: $!\n";
 
 walk_table {	# load documented functions into approriate hash
@@ -1184,7 +1184,7 @@ walk_table {	# load documented functions into approriate hash
 } \*DOC;
 
 for (sort keys %docfuncs) {
-    # Have you used a full for apidoc or just a func name?  
+    # Have you used a full for apidoc or just a func name?
     # Have you used Ap instead of Am in the for apidoc?
     warn "Unable to place $_!\n";
 }
@@ -1196,9 +1196,9 @@ perlapi - autogenerated documentation for the perl public API
 
 =head1 DESCRIPTION
 
-This file contains the documentation of the perl public API generated by 
-embed.pl, specifically a listing of functions, macros, flags, and variables 
-that may be used by extension writers.  The interfaces of any functions that 
+This file contains the documentation of the perl public API generated by
+embed.pl, specifically a listing of functions, macros, flags, and variables
+that may be used by extension writers.  The interfaces of any functions that
 are not listed here are subject to change without notice.  For this reason,
 blindly using functions listed in proto.h is to be avoided when writing
 extensions.
@@ -1244,19 +1244,19 @@ _EOE_
 
 close(DOC);
 
-open(GUTS, ">pod/perlintern.pod") or 
+open(GUTS, ">pod/perlintern.pod") or
 		die "Unable to create pod/perlintern.pod: $!\n";
 print GUTS <<'END';
 =head1 NAME
 
-perlintern - autogenerated documentation of purely B<internal> 
+perlintern - autogenerated documentation of purely B<internal>
 		 Perl functions
 
 =head1 DESCRIPTION
 
-This file is the autogenerated documentation of functions in the 
+This file is the autogenerated documentation of functions in the
 Perl interpreter that are documented using Perl's internal documentation
-format but are not marked as part of the Perl API. In other words, 
+format but are not marked as part of the Perl API. In other words,
 B<they are not for use in extensions>!
 
 =over 8
@@ -1272,8 +1272,8 @@ print GUTS <<'END';
 
 =head1 AUTHORS
 
-The autodocumentation system was originally added to the Perl core by 
-Benjamin Stuhl. Documentation is by whoever was kind enough to 
+The autodocumentation system was originally added to the Perl core by
+Benjamin Stuhl. Documentation is by whoever was kind enough to
 document their functions.
 
 =head1 SEE ALSO
@@ -1801,6 +1801,7 @@ Apd	|SV*	|newSVuv	|UV u
 Apd	|SV*	|newSVnv	|NV n
 Apd	|SV*	|newSVpv	|const char* s|STRLEN len
 Apd	|SV*	|newSVpvn	|const char* s|STRLEN len
+Apd	|SV*	|newSVpvn_share	|const char* s|STRLEN len|U32 hash
 Afpd	|SV*	|newSVpvf	|const char* pat|...
 Ap	|SV*	|vnewSVpvf	|const char* pat|va_list* args
 Apd	|SV*	|newSVrv	|SV* rv|const char* classname