perl-compiler/STATUS

5.8, 5.6 and earlier had a good core perl compiler, but we are much better.

Still missing in general are:

  - attribute handlers (i.e. run-time attributes)
  - compile-time perlio layers
  - wrong @- values

B::C is stable and used in production for -O0 and -O3. For bigger programs
not all methods in certain packages or eval strings might be detected,
you'd need to add them manually via -u<packagename>.

B::CC is very unstable, work is in progress. Certain alioth benchmarks are 6x faster.
Recursive function calls and certain dynamic ops are not yet supported.

The Bytecode compiler is only stable for >=5.8 except 5.18 threaded.
The CPAN Bytecode compiler is disabled for 5.6, we keep the old.
The old core compiler fails for 50% of the testcases.

Windows and other OS with strict linking <5.16 will fail to install due to some
not exported libperl symbols. Looks at the patches in ramblings.

Security: The latest released compiler version 1.43 is only supported up to 5.14.4.
5.16.x and 5.18.x upstream are too insecure to be recommended for production.
5.20 will finally properly handle unicode names, but identifiers and package
names are still handled as binary blobs, which could lead to TR39 issues.
Check your code for syntax spoofs, confusables, strip \\0 from package names
and enable use warnings 'syscalls'. There is no strict 'names' pragma yet.
See http://websec.github.io/unicode-security-guide/

C and CC: Same ok and less failures as with 5.6, 5.8 and 5.9.4.
In 5.8.8 and 5.8.9 we have much less errors in the testsuite for the
new CPAN compiler and the CORE compiler. See below.

Most B::C and B::CC bugs fixed.
Compatibility added for all major releases since 5.6.2

Open Problems for B::C:
  See google issues.

See below at the detailed status of the major releases.

TEST STATUS
-----------
Regularily tested on cygwin1.7, darwin 10.8/intel, centos4, centos5, centos6,
debian5, debian6, freebsd7, freebsd8, solaris10/intel sunpro, openbsd49, netbsd.
With the respective default gcc and clang compilers, with the latest address-sanitizer
versions.

Not so regurarily on darwin 10.4/ppc, strawberry-5.10.1, strawberry-5.12.2,
strawberry-5.14, strawberry-5.16 and activeperl-5.10.1/msvc8

List of failed tests.

CORE (old)
----

5.6.2:
t/bytecode      3,6,8..10,12,15,16,18,28,31,35,38,39
t/c             8,15,16,22,27,28,31			   | 27 worked in 5.6.2!
t/c_o1          8,15,16,22,27,28,31
t/c_o2          8,15,16,22,27,28,31
t/cc            15,18,21,25,27,28,30..32
t/cc_o1         15,18,21,25,27,28,30..32
t/cc_o2         10,15,16,18,21,25,26,27,28,30..32

5.8:  			                          	   | non-threaded
t/bytecode      27,44,33,39
t/c             11,14,15,20,23,27..29,31,101,102 	   | 5,7-12,14-20,22-23,25,27,28,30,31
t/c_o1          1,3-8,10..12,14,15,17..25,27..29,31,101,102| 7-12,14-20,22-23,25,27,28,30,31
t/c_o2          1,3-12,14,15,17..25,27..29,31,101,102      | 7-12,14-20,22-23,25,27,28,30,31
t/cc            7,11,14,15,18..21,23..25,28..32,101..103	
t/cc_o1         7,11,14,15,18..21,23..32,101..103		
t/cc_o2         7,10,11,14..16,18-21,23..32,101..103

Recipe:
  p=perl5.6.2
  t/testc.sh -q -c
  for t in $(seq -f"%02.0f" 32); do rm ccode 2>/dev/null; $p -MO=C,-occode.c ccode$t.pl 2>/dev/null && $p script/cc_harness ccode.c -o ccode >/dev/null; echo -n "$t: "; $p ccode$t.pl; echo -n " => "; ./ccode; echo; done
  p=perl5.8.9
  for t in $(seq -f"%02.0f" 35); do rm ccode 2>/dev/null; $p -MO=C,-occode.c ccode$t.pl 2>/dev/null && $p script/cc_harness -Bstatic ccode.c -o ccode >/dev/null; echo -n "$t: "; $p ccode$t.pl; echo -n " => "; ./ccode; echo; done
  p=perl5.8.9d-nt
  for t in $(seq -f"%02.0f" 35); do rm ccode 2>/dev/null; $p -MO=C,-occode.c ccode$t.pl 2>/dev/null && $p script/cc_harness -Bdynamic ccode.c -o ccode >/dev/null; echo -n "$t: "; $p ccode$t.pl; echo -n " => "; ./ccode; echo; done


B::C (new)
----
t/testc.sh -q -c; t/testcc.sh -q -c or make test TEST_VERBOSE=1

See t/test.pl for the TODO tests:
Only 42..43 < 5.12

CPAN Modules
------------
See t/modules.t:is_todo() We only try to compile use module, not the testsuite.
We only try B::C with -O3 so far.
The full module testsuite is run with t/testm.sh -t [OPTS] Module

Compile-time status from top100:
5.6.2      fail 1%  Sub::Name
5.8.5      fail 1%  DateTime
5.8.8      fail 1%  Test::Tester
5.8.9      fail 2%  ExtUtils::CBuilder DateTime
5.10.1     pass 100% (but PMOP->pregcomp is broken)
5.12.5     fail 1%  ExtUtils::CBuilder
5.14.4     pass 100%
5.16.3     fail 1%  Module::Build
5.18.2     fail 2%  ExtUtils::ParseXS Module::Build

Run-time tests not yet fully done

5.19.8 status
-----------
Bytecode is better than 5.18 but still unstable, B::CC also

5.18 status
-----------
Bytecode is broken for threaded perls, B::CC worse than with 5.14

5.10, 5.12, 5.14, 5.16 status
-----------------------
TODO for B::C
  see google issues https://code.google.com/p/perl-compiler/issues/
  Most of them have either easy workarounds or are not fixable.
  - global destruction (use lexicals!),
  - attribute handlers (i.e. run-time attributes)
  - compile-time perlio layers

Fix CC 
  several other issues detected (and mostly fixed) by Heinz Knutzen
  minimize pad copies from local to pad
  label not defined (utf8::SWASHNEW)
  -faelem is fast but still a bit unstable
  -funroll-loops by Will Braswell not yet merged

DONE
----
fixed with 1.46:
  global destruction of our static objects

fixed with 1.44:
  SvLEN and PV ptr for empty shared hash keys
  cop_hints to support lexical numeric hints pragmas (use bytes, use open, ...)
  -O3 with ~ and ~~ formatstrings
  skip saving a cv on defined(&cv)
  format STDOUT/STDERR
  Save empty bodyless subs if they exist, for signal handlers, prototypes declarations
    and cvrefs
  PVMG PV overwriting the RV, overload sub

fixed with 1.43:
  static strings and heks with LEN=0
  restore of many more dynamic magic variables: @+,@-,$$,${^UNICODE} ${^UTF8LOCALE}
   $; $\ $, $/ $" $| $^A $^L $: $% $- $= $^H $^R
  and allow other GP entries for ENV, ARGV, ...
  do not set newGP for symbols, thus do not disturb pre-initialization, esp. XS CVs
  do not boot internal core XS packages twice
  better load-order for dynaloaded modules, which helps esp. on windows
  improved deeper walker, detect more missing empty packages
  HvAUX init without magic (iterators)
  new PADLIST type
  unicode and binary strings and heks
  COW support
  proper len of QR refs
  stash symtab magic for PMf_ONCE m?? and reset
  lexwarns
  (See Changes for all fixes)

fixed with 1.42:
  my_share_hek (global destruction)
  Turn off CvDYNFILE
  save @ISA of empty child classes

fixed with 1.40:
  static PerlIO Layers
  synced %INC
  defer eval section after dl_init

fixed with 1.39:
  improved eval AUTOLOAD

fixed with 1.37:
  fixed wrong test 46, test for Exporter STASH in *main:: STASH
  copy-on-grow with LEN=0 and FAKE clash with share_hek
  share_hek re-implemented
  init of READONLY hash keys
  re-hash everything at startup (oCERT-2011-003)
  find UNIVERSAL methods, load SelectSaver with IO
  hv_clear_placeholders
  %+, %-, %!
  %SIG
  magic->PTR when SV (>5.6)
  attributes::reftype
  inc_cleanup (partially)
  CV prototypes (>5.10)
  ignore aelemfast SPECIAL pads (5.8.[45])
  strip version object overload from XS packages (i91)
  restore stdio handles from BEGIN blocks (Test::NoWarnings)
  B::COP::stashflags (>5.15.4)
  lost PL_regex_pad, (5.15 threaded)

fixed with 1.36:
  5.15 XSLoader and hash init
  support lexical warnings
  better __DATA__ detection and support, 
    still IO::File not IO::Scalar handle though
  fixed test 29 mostly (use IO)

fixed with 1.35:
  improve package_pv detection for methods,
  detect previously missing packages within the main source file 
  run-time %ENV

fixed with 1.32:
  improved scanner, try_isa, mark_package force, ...
  do not gp_free shared GPs 
  Internals::V
  dl_init of cached deleted packages

fixed with 1.30:
  cc_queue sort 18 ccpp
  dl_init regression
  xs_init (soname by context)
  5.14 support
  package_pv detection for method_named
  AUTOLOAD goto xsub and SelfLoader esp. on 5.8 (27). 
    use AutoLoader works okay. (test 27, 31)
  >5.11.3 test 32 catch evaltry die
  fixed test 29 >5.10 DEBUGGING for -O0 (use IO)

fixed xpvio off-by-one error for 5.10 (test 29)

mark a package which is autoloaded from XS

fixed forbidden REGEXP IVX/NVX access since 5.12

fixed evaltry (test 12), NVX was shared with 2 xpad_cop_seq ints
  which accidently just worked before 1.17, but not after using the %g 
  representation changed with 1.16. Also fixed in Bytecode, fixing tests 9,10,12.

fixed several minor bugs only in modules, no short testcases yet. See Changes

fixed PP_ENTEREVAL (CC test 12) for 5.10 with 1.14.
  Nullify ending retop for the string to CALLRUNOPS.

fixed __DATA__ IO (test 15) on 5.10 and 5.11 with 1.12. 
  On 5.6 it is hard to fix (re-implement PerlIO::scalar).

fixed RV => IV on blead (test 16 tiearray magic obj HVref) with 1.11

fixed GV -> BM magic (index) without needing fbm_compile with 1.09. Just 5.8.9 not.

fixed non-xsub AUTOLOAD (31) with 1.08

ccode17_o1 namepad[1] to PL_sv_undef 

GVCV for 5.11 (27)

runtime require $scalar (28)

RVs for 5.11 (29)

index (fbm_compile) for GVs fixed with 1.04_31

test 14+23 destruction of GvPVX of the empty main:: stash fixed by adding a dummy.

cccode19 sort failure via custom sortcv fixed with B::CC 1.02_03. endless loop

autoload subs from main::, from packages it works ok (test 8)
	fixed with 1.04_25

panic: illegal pad in pad_new: 0x18c4368[0x18cf6e8] with DEBUGGING only
        CvPADLIST: curpad<=>comppad
        fixed with 1.04_22

pvx: seems to be fixed now in bc, and c
  With the move of the pvx field from xpv to the sv, we have to solve 
  that differently for the Bytecode and C backend.
  Bytecode can simply mimic the old XPV behaviour of a 3 field struct 
  (pvx, cur, len) to simplify pv handling.

hv: crash at invalid entry in hv_store in B::HV::save fixed

hek: new implementation, needs static optimization via heksect

regexp: match works, split still broken

bc 10: padv+sassign => Modification of a read-only value attempted at 
bytecode10.pl line 1. Only on cygwin, not on linux!
The bytecode is exactly the same, it must be pp_entersub() with &$cv()
Is FAKE flag of the padsv is missing or should we check for readonly pads?
  g  <1> entersub[t4] vKS/TARG,1
  => Perl_sv_force_normal_flags()
	if (SvREADONLY(sv) && (!SvFAKE(sv)) && (IN_PERL_RUNTIME)) => die
	SV = NULL(0x0) at 0x12207c0
	  REFCNT = 2147483129
	  FLAGS = (READONLY)
-Dt crash fixed by core patch pl-dump-const.patch

cop_io status?
  http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/2006-05/msg00770.html

5.8 status
----------
I've restored full 5.8 backwards compatibility, mainly for test comparison.
But since the new B::C compiler is better than the CORE compiler, it is installed.

TEST COVERAGE
-------------
Bytecode:
coverage for ret(0) ldsv(1) ldop(2) stsv(3) stop(4) stpv(5) ldspecsv(6) 
ldspecsvx(7) newsv(8) newsvx(9) nop(10) newop(11) newopx(12) newopn(13) 
newpv(14) pv_cur(15) pv_free(16) sv_upgrade(17) sv_refcnt(18) sv_refcnt_add(19) 
sv_flags(20) xrv(21) xpv(22) xpv_cur(23) xpv_len(24) xiv(25) xnv(26) 
xlv_targoff(27) xlv_targlen(28) xlv_targ(29) xlv_type(30) xbm_useful(31) 
xbm_previous(32) xbm_rare(33) xfm_lines(34) comment(35) xio_lines(36) xio_page(37) 
xio_page_len(38) xio_lines_left(39) xio_top_name(40) xio_top_gv(41) xio_fmt_name(42) 
xio_fmt_gv(43) xio_bottom_name(44) xio_bottom_gv(45) xio_type(46) xio_flags(47) 
xcv_xsubany(48) xcv_stash(49) xcv_start(50) xcv_root(51) xcv_gv(52) xcv_file(53) 
xcv_depth(54) xcv_padlist(55) xcv_outside(56) xcv_outside_seq(57) xcv_flags(58) 
av_extend(59) av_pushx(60) av_push(61) xav_fill(62) xav_max(63) xav_flags(64) 
xhv_name(65) hv_store(66) sv_magic(67) mg_obj(68) mg_private(69) mg_flags(70) 
mg_name(71) mg_namex(72) xmg_stash(73) gv_fetchpv(74) gv_fetchpvx(75) gv_stashpv(76) 
gv_stashpvx(77) gp_sv(78) gp_refcnt(79) gp_refcnt_add(80) gp_av(81) gp_hv(82) 
gp_cv(83) gp_file(84) gp_io(85) gp_form(86) gp_cvgen(87) gp_line(88) gp_share(89) 
xgv_flags(90) op_next(91) op_sibling(92) op_ppaddr(93) op_targ(94) op_type(95) 
op_opt(96) op_latefree(97) op_latefreed(98) op_attached(99) op_first(102) op_last(103) 
op_pmreplroot(105) op_pmreplstart(106) op_pmreplrootpo(108) op_pmstash(109) 
op_pmreplrootgv(110) pregcomp(111) op_pmflags(112) unused(113) op_reflags(114) 
op_sv(115) op_pv(117) op_pv_tr(118) op_redoop(119) op_nextop(120) op_lastop(121) 
cop_label(122) cop_stash(125) cop_filegv(126) push_begin(134) push_init(135) 
push_end(136) curstash(137) defstash(138) data(139) incav(140) load_glob(141) 
regex_padav(142) comppad_name(144) xgv_stash(145) signal(146) formfeed(147)

Abbrevations
------------
bc 	B::ByteCode 
c  	B::C
cc 	B::CC
-D 	-DDEBUGGING perl, also used as d version suffix, eg 5.8.8d
-nt 	not threaded perl

2014-01-15 14:48:08 rurban