[PATCH] refactor pp_tied

[p5pRT]

Migrated from rt.perl.org#121969 (status was 'resolved')

Searchable as RT121969$

[p5pRT]

From @bulk88

Created by @bulk88

See attached patch.

Perl Info

Flags:
       category=core
       severity=low

Site configuration information for perl 5.20.0:

Configured by Owner at Sat May 17 23:49:31 2014.

Summary of my perl5 (revision 5 version 20 subversion 0) configuration:
     Local Commit: 5b1fb5914dd2ffb35ae3286bcf8e8ee236940710
     Ancestor: e023b52d29900981e0c68349b3ec306d85c0716d
     Platform:
       osname=MSWin32, osvers=5.1, archname=MSWin32-x86-multi-thread
       uname=''
       config_args='undef'
       hint=recommended, useposix=true, d_sigaction=undef
       useithreads=define, usemultiplicity=define
       use64bitint=undef, use64bitall=undef, uselongdouble=undef
       usemymalloc=n, bincompat5005=undef
     Compiler:
       cc='cl', ccflags ='-nologo -GF -W3 -O1 -MD -Zi -DNDEBUG -G7 -GL
-DWIN32 -D_CONSOLE -DNO_STRICT  -DPERL_TEXTMODE_SCRIPTS
-DPERL_HASH_FUNC_ONE_AT_A_TIME -DPERL_IMPLICIT_CONTEXT
-DPERL_IMPLICIT_SYS -DUSE_PERLIO -D_USE_32BIT_TIME_T',
       optimize='-O1 -MD -Zi -DNDEBUG -G7 -GL',
       cppflags='-DWIN32'
       ccversion='13.10.6030', gccversion='', gccosandvers=''
       intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
       d_longlong=undef, longlongsize=8, d_longdbl=define, longdblsize=8
       ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='__int64',
lseeksize=8
       alignbytes=8, prototype=define
     Linker and Libraries:
       ld='link', ldflags ='-nologo -nodefaultlib -debug -opt:ref,icf
-ltcg  -libpath:"c:\perl519\lib\CORE"  -machine:x86'
       libpth="C:\Program Files\Microsoft Visual Studio .NET 2003\VC7\lib"
       libs=oldnames.lib kernel32.lib user32.lib gdi32.lib winspool.lib
comdlg32.lib advapi32.lib shell32.lib ole32.lib oleaut32.lib
netapi32.lib uuid.lib ws2_32.lib mpr.lib winmm.lib  version.lib
odbc32.lib odbccp32.lib comctl32.lib msvcrt.lib
       perllibs=oldnames.lib kernel32.lib user32.lib gdi32.lib
winspool.lib  comdlg32.lib advapi32.lib shell32.lib ole32.lib
oleaut32.lib  netapi32.lib uuid.lib ws2_32.lib mpr.lib winmm.lib
version.lib odbc32.lib odbccp32.lib comctl32.lib msvcrt.lib
       libc=msvcrt.lib, so=dll, useshrplib=true, libperl=perl520.lib
       gnulibc_version=''
     Dynamic Linking:
       dlsrc=dl_win32.xs, dlext=dll, d_dlsymun=undef, ccdlflags=' '
       cccdlflags=' ', lddlflags='-dll -nologo -nodefaultlib -debug
-opt:ref,icf -ltcg  -libpath:"c:\perl519\lib\CORE"  -machine:x86'

Locally applied patches:
       RC1
       602f5d5ad824f3fd87b13b2613c3ff8ea5321bf8
       7e81d5c4f446d69f52760d5f05e193bbed8cd3db
       5b1fb5914dd2ffb35ae3286bcf8e8ee236940710


@INC for perl 5.20.0:
       C:/perl519/site/lib
       C:/perl519/lib
       .


Environment for perl 5.20.0:
       HOME (unset)
       LANG (unset)
       LANGUAGE (unset)
       LD_LIBRARY_PATH (unset)
       LOGDIR (unset)
       PATH=C:\perl519\bin;C:\Program Files\Microsoft Visual Studio .NET
2003\Common7\IDE;C:\Program Files\Microsoft Visual Studio .NET
2003\VC7\BIN;C:\Program Files\Microsoft Visual Studio .NET
2003\Common7\Tools;C:\Program Files\Microsoft Visual Studio .NET
2003\Common7\Tools\bin\prerelease;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\system32\wbem;
       PERL_BADLANG (unset)
       SHELL (unset)

[p5pRT]

From @bulk88

0001-refactor-pp_tied.patch

From 45753263334050eb7b0da59d7dc0b31f9ffc66db Mon Sep 17 00:00:00 2001
From: Daniel Dragan <bulk88@hotmail.com>
Date: Tue, 27 May 2014 17:14:20 -0400
Subject: [PATCH] refactor pp_tied

remove some redundant code regarding stack handling

-removed:
  -4/-8 pop on SP
  +4/+8 push on SP
  PUTBACK

function's machine code size dropped from 0xC5 to 0xBD bytes on VC2003
---
 pp_sys.c |   14 ++++++++------
 1 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/pp_sys.c b/pp_sys.c
index 9f97177..175fad3 100644
--- a/pp_sys.c
+++ b/pp_sys.c
@@ -1003,21 +1003,23 @@ PP(pp_tied)
     dVAR;
     dSP;
     const MAGIC *mg;
-    SV *sv = POPs;
+    dTOPss;
     const char how = (SvTYPE(sv) == SVt_PVHV || SvTYPE(sv) == SVt_PVAV)
 		? PERL_MAGIC_tied : PERL_MAGIC_tiedscalar;
 
     if (isGV_with_GP(sv) && !SvFAKE(sv) && !(sv = MUTABLE_SV(GvIOp(sv))))
-	RETPUSHUNDEF;
+	goto ret_undef;
 
     if (SvTYPE(sv) == SVt_PVLV && LvTYPE(sv) == 'y' &&
-	!(sv = defelem_target(sv, NULL))) RETPUSHUNDEF;
+	!(sv = defelem_target(sv, NULL))) goto ret_undef;
 
     if ((mg = SvTIED_mg(sv, how))) {
-	PUSHs(SvTIED_obj(sv, mg));
-	RETURN;
+	SETs(SvTIED_obj(sv, mg));
+	return NORMAL; /* PUTBACK not needed, pp_tied never moves SP */
     }
-    RETPUSHUNDEF;
+    ret_undef:
+    SETs(&PL_sv_undef);
+    return NORMAL;
 }
 
 PP(pp_dbmopen)
-- 
1.7.9.msysgit.0

[p5pRT]

From @bulk88

On Tue May 27 14​:16​:49 2014, bulk88 wrote​:

This is a bug report for perl from bulk88@​hotmail.com,
generated with the help of perlbug 1.40 running under perl 5.20.0.

-----------------------------------------------------------------
[Please describe your issue here]

See attached patch.

Interesting trivia, in Strawberry Perl 5.18, GCC optimize out the -4 and +4 to SP (and that is across function calls), it didn't optimize out the PUTBACK. Quite interesting the GCC optimizer looks so many lines back/forwards.

--
bulk88 ~ bulk88 at hotmail.com

[p5pRT]

From @tonycoz

On Tue May 27 14​:16​:49 2014, bulk88 wrote​:

See attached patch.

Thanks, applied as b3cf482.

Tony

[p5pRT]

The RT System itself - Status changed from 'new' to 'open'

[p5pRT]

@tonycoz - Status changed from 'open' to 'resolved'