dslinux/user/perl/ext/B/ramblings cc.notes curcop.runtime flip-flop magic reg.alloc runtime.porting
cayenne
dslinux_cayenne at user.in-berlin.de
Mon Dec 4 17:59:08 CET 2006
Update of /cvsroot/dslinux/dslinux/user/perl/ext/B/ramblings
In directory antilope:/tmp/cvs-serv17422/ext/B/ramblings
Added Files:
cc.notes curcop.runtime flip-flop magic reg.alloc
runtime.porting
Log Message:
Adding fresh perl source to HEAD to branch from
--- NEW FILE: reg.alloc ---
while ($i--) {
foo();
}
exit
PP code if i an int register if i an int but not a
(i.e. can't be register (i.e. can be
implicitly invalidated) implicitly invalidated)
nextstate
enterloop
loop:
gvsv GV (0xe6078) *i validates i validates i
postdec invalidates $i invalidates $i
and if_false goto out;
i valid; $i invalid i valid; $i invalid
i valid; $i invalid i valid; $i invalid
nextstate
pushmark
gv GV (0xe600c) *foo
entersub validates $i; invals i
unstack
goto loop:
i valid; $i invalid
out:
leaveloop
nextstate
exit
--- NEW FILE: magic ---
sv_magic()
----------
av.c
av_store()
Storing a non-undef element into an SMAGICAL array, av,
assigns the equivalent lowercase form of magic (of the first
MAGIC in the chain) to the value (with obj = av, name = 0 and
namlen = array index).
gv.c
gv_init()
Initialising gv assigns '*' magic to it with obj = gv, name =
GvNAME and namlen = GvNAMELEN.
gv_fetchpv()
@ISA gets 'I' magic with obj = gv, zero name and namlen.
%OVERLOAD gets 'A' magic with obj = gv, zero name and namlen.
$1 to $9, $&, $`, $', $+ get '\0' magic with obj = gv,
name = GvNAME and namlen = len ( = 1 presumably).
Gv_AMupdate()
Stashes for overload magic seem to get 'c' magic with obj = 0,
name = &amt and namlen = sizeof(amt).
hv_magic(hv, gv, how)
Gives magic how to hv with obj = gv and zero name and namlen.
mg.c
mg_copy(sv, nsv, key, klen)
Traverses the magic chain of sv. Upper case forms of magic
(only) are copied across to nsv, preserving obj but using
name = key and namlen = klen.
magic_setpos()
LvTARG of a PVLV gets 'g' magic with obj = name = 0 and namlen = pos.
op.c
mod()
PVLV operators give magic to their targs with
obj = name = namlen = 0. OP_POS gives '.', OP_VEC gives 'v'
and OP_SUBSTR gives 'x'.
perl.c
magicname(sym, name, namlen)
Fetches/creates a GV with name sym and gives it '\0' magic
with obj = gv, name and namlen as passed.
init_postdump_symbols()
Elements of the environment get given SVs with 'e' magic.
obj = sv and name and namlen point to the actual string
within env.
pp.c
pp_av2arylen()
$#foo gives '#' magic to the new SV with obj = av and
name = namlen = 0.
pp_study()
SV gets 'g' magic with obj = name = namlen = 0.
pp_substr()
PVLV gets 'x' magic with obj = name = namlen = 0.
pp_vec()
PVLV gets 'x' magic with obj = name = namlen = 0.
pp_hot.c
pp_match()
m//g gets 'g' magic with obj = name = namlen = 0.
pp_sys.c
pp_tie()
sv gets magic with obj = sv and name = namlen = 0.
If an HV or an AV, it gets 'P' magic, otherwise 'q' magic.
pp_dbmopen()
'P' magic for the HV just as with pp_tie().
pp_sysread()
If tainting, the buffer SV gets 't' magic with
obj = name = namlen = 0.
sv.c
sv_setsv()
Doing sv_setsv(dstr, gv) gives '*' magic to dstr with
obj = dstr, name = GvNAME, namlen = GvNAMELEN.
util.c
fbm_compile()
The PVBM gets 'B' magic with obj = name = namlen = 0 and SvVALID
is set to indicate that the Boyer-Moore table is valid.
magic_setbm() just clears the SvVALID flag.
hv_magic()
----------
gv.c
gv_fetchfile()
With perldb, the HV of a gvfile gv gets 'L' magic with obj = gv.
gv_fetchpv()
%SIG gets 'S' magic with obj = siggv.
init_postdump_symbols()
%ENV gets 'E' magic with obj = envgv.
--- NEW FILE: runtime.porting ---
Notes on porting the perl runtime PP engine.
Importance: 1 = who cares?, 10 = vital
Difficulty: 1 = trivial, 10 = very difficult. Level assumes a
reasonable implementation of the SV and OP API already ported.
OP Import Diff Comments
null 10 1
stub 10 1
scalar 10 1
pushmark 10 1 PUSHMARK
wantarray 7 3 cxstack, dopoptosub
const 10 1
gvsv 10 1 save_scalar
gv 10 1
gelem 3 3
padsv 10 2 SAVECLEARSV, provide_ref
padav 10 2
padhv 10 2
padany 1 1
pushre 7 3 pushes an op. Blech.
rv2gv 6 5
rv2sv 10 4
av2arylen 7 3 sv_magic
rv2cv 8 5 sv_2cv
anoncode 7 6 cv_clone
prototype 4 4 sv_2cv
refgen 8 3
srefgen 8 2
ref 8 3
bless 7 3
backtick 5 4
glob 5 2 do_readline
readline 8 2 do_readline
rcatline 8 2
regcmaybe 8 1
regcreset 8 1
regcomp 8 9 pregcomp
match 8 10
qr 8 1
subst 8 10
substcont 8 7
trans 7 4 do_trans
sassign 10 3 mg_find, SvSETMAGIC
aassign 10 5
chop 8 3 do_chop
schop 8 3 do_chop
chomp 8 3 do_chomp
schomp 8 3 do_chomp
defined 10 2
undef 10 3
study 4 5
pos 8 3 PVLV, mg_find
preinc 10 2 sv_inc, SvSETMAGIC
i_preinc
predec 10 2 sv_dec, SvSETMAGIC
i_predec
postinc 10 2 sv_dec, SvSETMAGIC
i_postinc
postdec 10 2 sv_dec, SvSETMAGIC
i_postdec
pow 10 1
multiply 10 1
i_multiply 10 1
divide 10 2
i_divide 10 1
modulo 10 2
i_modulo 10 1
repeat 6 4
add 10 1
i_add 10 1
subtract 10 1
i_subtract 10 1
concat 10 2 mg_get
stringify 10 2 sv_setpvn
left_shift 10 1
right_shift 10 1
lt 10 1
i_lt 10 1
gt 10 1
i_gt 10 1
le 10 1
i_le 10 1
ge 10 1
i_ge 10 1
eq 10 1
i_eq 10 1
ne 10 1
i_ne 10 1
ncmp 10 1
i_ncmp 10 1
slt 10 2
sgt 10 2
sle 10 2
sge 10 2
seq 10 2 sv_eq
sne 10 2
scmp 10 2
bit_and 10 2
bit_xor 10 2
bit_or 10 2
negate 10 3
i_negate 10 1
not 10 1
complement 10 3
atan2 6 1
sin 6 1
cos 6 1
rand 5 2
srand 5 2
exp 6 1
log 6 2
sqrt 6 2
int 10 2
hex 9 2
oct 9 2
abs 10 1
length 10 1
substr 10 4 PVLV
vec 5 4
index 9 3
rindex 9 3
sprintf 9 4 do_sprintf
formline 6 7
ord 6 2
chr 6 2
crypt 3 2
ucfirst 6 2
lcfirst 6 2
uc 6 2
lc 6 2
quotemeta 6 3
rv2av 10 3 save_svref, mg_get, save_ary
aelemfast 10 2 av_fetch
aelem 10 3
aslice 9 4
each 10 3 hv_iternext
values 10 3 do_kv
keys 10 3 do_kv
delete 10 3
exists 10 3
rv2hv 10 3 save_svref, mg_get, save_ary, do_kv
helem 10 3 save_svref, provide_ref
hslice 9 4
unpack 9 6 lengthy
pack 9 6 lengthy
split 9 9
join 10 4 do_join
list 10 2
lslice 9 4
anonlist 10 2
anonhash 10 3
splice 9 6
push 10 2
pop 10 2
shift 10 2
unshift 10 2
sort 6 7
reverse 9 4
grepstart 6 5 modifies flow of control
grepwhile 6 5 modifies flow of control
mapstart 1 1
mapwhile 6 5 modifies flow of control
range 7 3 modifies flow of control
flip 7 4 modifies flow of control
flop 7 4 modifies flow of control
and 10 3 modifies flow of control
or 10 3 modifies flow of control
xor
cond_expr 10 3 modifies flow of control
andassign 7 3 modifies flow of control
orassign 7 3 modifies flow of control
method 8 5
entersub 10 7
leavesub 10 5
leavesublv
caller 2 8
warn 9 3
die 9 3
reset 2 2
lineseq 1 1
nextstate 10 1 Update stack_sp from cxstack. FREETMPS.
dbstate 3 7
unstack
enter 10 3 cxstack, ENTER, SAVETMPS, PUSHBLOCK
leave 10 3 cxstack, SAVETMPS, LEAVE, POPBLOCK
scope 1 1
enteriter 9 4 cxstack
iter 9 3 cxstack
enterloop 10 4
leaveloop 10 4
return 10 5
last 9 6
next 9 6
redo 9 6
dump 1 9 pp_goto
goto 6 9
exit 9 2 my_exit
open 9 5 do_open
close 9 3 do_close
pipe_op 7 4
fileno 9 2
umask 4 2
binmode 4 2
tie 5 5 pp_entersub
untie 5 2 sv_unmagic
tied 5 2
dbmopen 4 5
dbmclose 4 2
sselect 4 4
select 7 3
getc 7 2
read 8 2 pp_sysread
enterwrite 4 4 doform
leavewrite 4 5
prtf 4 4 do_sprintf
print 8 6
sysopen 8 2
sysseek 8 2
sysread 8 4
syswrite 8 4 pp_send
send 8 4
recv 8 4 pp_sysread
eof 9 2
tell 9 3
seek 9 2
truncate 8 3
fcntl 8 4 pp_ioctl
ioctl 8 4
flock 8 2
socket 5 3
sockpair 5 3
bind 5 3
connect 5 3
listen 5 3
accept 5 3
shutdown 5 2
gsockopt 5 3 pp_ssockopt
ssockopt 5 3
getsockname 5 3 pp_getpeername
getpeername 5 3
lstat 5 4 pp_stat
stat 5 4 lengthy
ftrread 5 2 cando
ftrwrite 5 2 cando
ftrexec 5 2 cando
fteread 5 2 cando
ftewrite 5 2 cando
fteexec 5 2 cando
ftis 5 2 cando
fteowned 5 2 cando
ftrowned 5 2 cando
ftzero 5 2 cando
ftsize 5 2 cando
ftmtime 5 2 cando
ftatime 5 2 cando
ftctime 5 2 cando
ftsock 5 2 cando
ftchr 5 2 cando
ftblk 5 2 cando
ftfile 5 2 cando
ftdir 5 2 cando
ftpipe 5 2 cando
ftlink 5 2 cando
ftsuid 5 2 cando
ftsgid 5 2 cando
ftsvtx 5 2 cando
fttty 5 2 cando
fttext 5 4
ftbinary 5 4 fttext
chdir
chown
chroot
unlink
chmod
utime
rename
link
symlink
readlink
mkdir
rmdir
open_dir
readdir
telldir
seekdir
rewinddir
closedir
fork
wait
waitpid
system
exec
kill
getppid
getpgrp
setpgrp
getpriority
setpriority
time
tms
localtime
gmtime
alarm
sleep
shmget
shmctl
shmread
shmwrite
msgget
msgctl
msgsnd
msgrcv
semget
semctl
semop
require 6 9 doeval
dofile 6 9 doeval
entereval 6 9 doeval
leaveeval 6 5
entertry 7 4 modifies flow of control
leavetry 7 3
ghbyname
ghbyaddr
ghostent
gnbyname
gnbyaddr
gnetent
gpbyname
gpbynumber
gprotoent
gsbyname
gsbyport
gservent
shostent
snetent
sprotoent
sservent
ehostent
enetent
eprotoent
eservent
gpwnam
gpwuid
gpwent
spwent
epwent
ggrnam
ggrgid
ggrent
sgrent
egrent
getlogin
syscall
lock 6 1
threadsv 6 2 unused if not USE_5005THREADS, absent post 5.8
setstate 1 1 currently unused anywhere
method_named 10 2
--- NEW FILE: flip-flop ---
PP(pp_range)
{
if (GIMME == G_ARRAY)
return NORMAL;
if (SvTRUEx(PAD_SV(PL_op->op_targ)))
return cLOGOP->op_other;
else
return NORMAL;
}
pp_range is a LOGOP.
In list context, it just returns op_next.
In scalar context it checks the truth of targ and returns
op_other if true, op_next if false.
flip is an UNOP.
It "looks after" its child which is always a pp_range LOGOP.
In list context, it just returns the child's op_other.
In scalar context, there are three possible outcomes:
(1) set child's targ to 1, our targ to 1 and return op_next.
(2) set child's targ to 1, our targ to 0, sp-- and return child's op_other.
(3) Blank targ and TOPs and return op_next.
Case 1 happens for a "..." with a matching lineno... or true TOPs.
Case 2 happens for a ".." with a matching lineno... or true TOPs.
Case 3 happens for a non-matching lineno or false TOPs.
$a = lhs..rhs;
,-------> range
^ / \
| true/ \false
| / \
first| lhs rhs
| \ first /
^--- flip <----- flop
\ /
\ /
sassign
/* range */
if (SvTRUE(curpad[op->op_targ]))
goto label(op_other);
/* op_next */
...
/* flip */
/* For "..." returns op_next. For ".." returns op_next or op_first->op_other */
/* end of basic block */
goto out;
label(range op_other):
...
/* flop */
out:
...
--- NEW FILE: cc.notes ---
At entry to each basic block, the following can be assumed (and hence
must be forced where necessary at the end of each basic block):
The shadow stack @stack is empty.
For each lexical object in @pad, VALID_IV holds for each T_INT,
VALID_DOUBLE holds for each T_DOUBLE and VALID_SV holds otherwise.
The C shadow variable sp holds the stack pointer (not necessarily stack_sp).
write_back_stack
Writes the contents of the shadow stack @stack back to the real stack.
A write-back of each object in the stack is forced so that its
backing SV contains the right value and that SV is then pushed onto the
real stack. On return, @stack is empty.
write_back_lexicals
Forces a write-back (i.e. achieves VALID_SV), where necessary, for each
lexical object in @pad. Objects with the TEMPORARY flag are skipped. If
write_back_lexicals is called with an (optional) argument, then it is
taken to be a bitmask of more flags: any lexical object with one of those
flags set is also skipped and not written back to its SV.
invalidate_lexicals($avoid)
The VALID_INT and VALID_DOUBLE flags are turned off for each lexical
object in @pad whose flags field doesn't overlap with $avoid.
reload_lexicals
For each necessary lexical object in @pad, makes sure that VALID_IV
holds for objects of type T_INT, VALID_DOUBLE holds for objects for
type T_DOUBLE, and VALID_SV holds for other objects. An object is
considered for reloading if its flags field does not overlap with the
(optional) argument passed to reload_lexicals.
--- NEW FILE: curcop.runtime ---
PP code uses of curcop
----------------------
pp_rv2gv
when a new glob is created for an OPpLVAL_INTRO,
curcop->cop_line is stored as GvLINE() in the new GP.
pp_bless
curcop->cop_stash is used as the stash in the one-arg form of bless
pp_repeat
tests (curcop != &compiling) to warn "Can't x= to readonly value"
pp_pos
pp_substr
pp_index
pp_rindex
pp_aslice
pp_lslice
pp_splice
curcop->cop_arybase
pp_sort
curcop->cop_stash used to determine whether to gv_fetchpv $a and $b
pp_caller
tests (curcop->cop_stash == debstash) to determine whether
to set DB::args
pp_reset
resets vars in curcop->cop_stash
pp_dbstate
sets curcop = (COP*)op
doeval
compiles into curcop->cop_stash
pp_nextstate
sets curcop = (COP*)op
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