Re: [Tarantool-patches] [PATCH v2 luajit 1/3] gdb: introduce luajit-gdb extension

[Igor Munkin <imun@tarantool.org>]

One more bug found while using the gdb built against Python 2.x. VM
state field is 32-bit length but was treated as 64-bit one. This led to
the following invalid output:

| (gdb) source ~/luajit-gdb.py 
| lj-gc command initialized
| lj-tab command initialized
| lj-str command initialized
| lj-state command initialized
| lj-stack command initialized
| lj-tv command initialized
| lj-arch command initialized
| luajit-gdb.py is successfully loaded
| (gdb) lj-state
| JIT state: IDLE
| GC state: PAUSE
| VM state: TRACE
| (gdb) p ((global_State *)L->glref.ptr32)->vmstate
| $1 = -1   # <-- VM state is INTERP and not valid traceno

Fixed, squashed, force-pushed to the branch. Diff is below:

================================================================================

diff --git a/src/luajit-gdb.py b/src/luajit-gdb.py
index cccec1c..b6b3212 100644
--- a/src/luajit-gdb.py
+++ b/src/luajit-gdb.py
@@ -52,9 +52,6 @@ def tou64(val):
 def tou32(val):
     return cast('uint32_t', val) & 0xFFFFFFFF
 
-def i2notu64(val):
-    return ~int(val) & 0xFFFFFFFFFFFFFFFF
-
 def i2notu32(val):
     return ~int(val) & 0xFFFFFFFF
 
@@ -205,14 +202,14 @@ def J(g):
 
 def vm_state(g):
     return {
-        i2notu64(0): 'INTERP',
-        i2notu64(1): 'C',
-        i2notu64(2): 'GC',
-        i2notu64(3): 'EXIT',
-        i2notu64(4): 'RECORD',
-        i2notu64(5): 'OPT',
-        i2notu64(6): 'ASM',
-    }.get(int(tou64(g['vmstate'])), 'TRACE')
+        i2notu32(0): 'INTERP',
+        i2notu32(1): 'C',
+        i2notu32(2): 'GC',
+        i2notu32(3): 'EXIT',
+        i2notu32(4): 'RECORD',
+        i2notu32(5): 'OPT',
+        i2notu32(6): 'ASM',
+    }.get(int(tou32(g['vmstate'])), 'TRACE')
 
 def gc_state(g):
     return {

===============================================================================

On 05.02.20, Igor Munkin wrote:
> The provided luajit-gdb extenstion contains the following additional commands:
> * lj-arch -- dumps values of LJ_64 and LJ_GC64 macro definitions
> * lj-tv -- dumps the type and some GCobj info related to the given TValue
> * lj-str -- dumps the contents of the given GCstr
> * lj-tab -- dumps the contents of the given GCtab
> * lj-stack -- dumps Lua stack of the given lua_State
> * lj-state -- shows current VM, GC and JIT states
> * lj-gc -- shows current GC stats
> 
> Currently extension supports only x64 builds but respects LJ_GC64 value
> 
> Signed-off-by: Igor Munkin <imun@tarantool.org>
> ---
>  src/luajit-gdb.py | 684 ++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 684 insertions(+)
>  create mode 100644 src/luajit-gdb.py
> 
> diff --git a/src/luajit-gdb.py b/src/luajit-gdb.py
> new file mode 100644
> index 0000000..77da5e6
> --- /dev/null
> +++ b/src/luajit-gdb.py
> @@ -0,0 +1,684 @@
> +import re
> +import gdb
> +
> +gtype_cache = {}
> +
> +def gtype(typestr):
> +    global gtype_cache
> +    if typestr in gtype_cache:
> +        return gtype_cache[typestr]
> +
> +    m = re.match(r'((?:(?:struct|union) )?\S*)\s*[*]', typestr)
> +
> +    gtype = gdb.lookup_type(typestr) if m is None \
> +        else gdb.lookup_type(m.group(1)).pointer()
> +
> +    gtype_cache[typestr] = gtype
> +    return gtype
> +
> +def cast(typestr, val):
> +    return gdb.Value(val).cast(gtype(typestr))
> +
> +def lookup(symbol):
> +    variable, _ = gdb.lookup_symbol(symbol)
> +    return variable.value() if variable else None
> +
> +def parse_arg(arg):
> +    if not arg:
> +        return None
> +
> +    ret = gdb.parse_and_eval(arg)
> +
> +    if not ret:
> +        raise gdb.GdbError('table argument empty')
> +
> +    return ret
> +
> +def tou64(val):
> +    return cast('uint64_t', val) & 0xFFFFFFFFFFFFFFFF
> +
> +def tou32(val):
> +    return cast('uint32_t', val) & 0xFFFFFFFF
> +
> +def i2notu64(val):
> +    return ~int(val) & 0xFFFFFFFFFFFFFFFF
> +
> +def i2notu32(val):
> +    return ~int(val) & 0xFFFFFFFF
> +
> +def strx64(val):
> +    return hex(cast('uint64_t', val) & 0xFFFFFFFFFFFFFFFF)
> +
> +# Types {{{
> +
> +LJ_T = {
> +    'NIL'     : i2notu32(0),
> +    'FALSE'   : i2notu32(1),
> +    'TRUE'    : i2notu32(2),
> +    'LIGHTUD' : i2notu32(3),
> +    'STR'     : i2notu32(4),
> +    'UPVAL'   : i2notu32(5),
> +    'THREAD'  : i2notu32(6),
> +    'PROTO'   : i2notu32(7),
> +    'FUNC'    : i2notu32(8),
> +    'TRACE'   : i2notu32(9),
> +    'CDATA'   : i2notu32(10),
> +    'TAB'     : i2notu32(11),
> +    'UDATA'   : i2notu32(12),
> +    'NUMX'    : i2notu32(13),
> +}
> +
> +def typenames(value):
> +    return {
> +        LJ_T[k]: 'LJ_T' + k for k in LJ_T.keys()
> +    }.get(int(value), 'LJ_TINVALID')
> +
> +# }}}
> +
> +# Frames {{{
> +
> +FRAME_TYPE = 0x3
> +FRAME_P = 0x4
> +FRAME_TYPEP = FRAME_TYPE | FRAME_P
> +
> +FRAME = {
> +    'LUA': 0x0,
> +    'C': 0x1,
> +    'CONT': 0x2,
> +    'VARG': 0x3,
> +    'LUAP': 0x4,
> +    'CP': 0x5,
> +    'PCALL': 0x6,
> +    'PCALLH': 0x7,
> +}
> +
> +def frametypes(ft):
> +    return {
> +        FRAME['LUA']  : 'L',
> +        FRAME['C']    : 'C',
> +        FRAME['CONT'] : 'M',
> +        FRAME['VARG'] : 'V',
> +    }.get(ft, '?')
> +
> +def bc_a(ins):
> +    return (ins >> 8) & 0xff
> +
> +def frame_ftsz(framelink):
> +    return cast('ptrdiff_t', framelink['ftsz'] if LJ_FR2 \
> +        else framelink['fr']['tp']['ftsz'])
> +
> +def frame_pc(framelink):
> +    return cast('BCIns *', frame_ftsz(framelink)) if LJ_FR2 \
> +        else mref('BCIns *', framelink['fr']['tp']['pcr'])
> +
> +def frame_prevl(framelink):
> +    return framelink - (1 + LJ_FR2 + bc_a(frame_pc(framelink)[-1]))
> +
> +def frame_ispcall(framelink):
> +    return (frame_ftsz(framelink) & FRAME['PCALL']) == FRAME['PCALL']
> +
> +def frame_sized(framelink):
> +    return (frame_ftsz(framelink) & ~FRAME_TYPEP)
> +
> +def frame_prevd(framelink):
> +    return cast('TValue *', cast('char *', framelink) - frame_sized(framelink))
> +
> +def frame_type(framelink):
> +    return frame_ftsz(framelink) & FRAME_TYPE
> +
> +def frame_typep(framelink):
> +    return frame_ftsz(framelink) & FRAME_TYPEP
> +
> +def frame_islua(framelink):
> +    return frametypes(int(frame_type(framelink))) == 'L' \
> +        and int(frame_ftsz(framelink)) > 0
> +
> +def frame_prev(framelink):
> +    return frame_prevl(framelink) if frame_islua(framelink) \
> +        else frame_prevd(framelink)
> +
> +# }}}
> +
> +# Const {{{
> +
> +LJ_64 = str(gdb.parse_and_eval('IRT_PTR')) == 'IRT_P64'
> +
> +LJ_GC64 = str(gdb.parse_and_eval('IRT_PGC')) == 'IRT_P64'
> +
> +LJ_FR2 = LJ_GC64
> +
> +LJ_GCVMASK = ((1 << 47) - 1)
> +
> +PADDING = ' ' * len(':' + hex((1 << (47 if LJ_GC64 else 32)) - 1))
> +
> +# }}}
> +
> +def itype(o):
> +    return cast('uint32_t', o['it64'] >> 47) if LJ_GC64 else o['it']
> +
> +def mref(typename, obj):
> +    return cast(typename, obj['ptr64'] if LJ_GC64 else obj['ptr32'])
> +
> +def gcref(obj):
> +    return cast('GCobj *', obj['gcptr64'] if LJ_GC64
> +        else cast('uintptr_t', obj['gcptr32']))
> +
> +def gcval(obj):
> +    return cast('GCobj *', obj['gcptr64'] & LJ_GCVMASK if LJ_GC64
> +        else cast('uintptr_t', obj['gcptr32']))
> +
> +def L(L=None):
> +    # lookup a symbol for the main coroutine considering the host app
> +    for l in (L, *map(lambda l: lookup(l), (
> +        # LuaJIT main coro (see luajit/src/luajit.c)
> +        'globalL',
> +        # Tarantool main coro (see tarantool/src/lua/init.h)
> +        'tarantool_L',
> +        # TODO: Add more
> +    ))):
> +        if l:
> +            return cast('lua_State *', l)
> +
> +def G(L):
> +    return mref('global_State *', L['glref'])
> +
> +def J(g):
> +    typeGG = gtype('GG_State')
> +
> +    return cast('jit_State *', int(cast('char *', g))
> +        - int(typeGG['g'].bitpos / 8)
> +        + int(typeGG['J'].bitpos / 8)
> +    )
> +
> +def vm_state(g):
> +    return {
> +        i2notu64(0): 'INTERP',
> +        i2notu64(1): 'C',
> +        i2notu64(2): 'GC',
> +        i2notu64(3): 'EXIT',
> +        i2notu64(4): 'RECORD',
> +        i2notu64(5): 'OPT',
> +        i2notu64(6): 'ASM',
> +    }.get(int(tou64(g['vmstate'])), 'TRACE')
> +
> +def gc_state(g):
> +    return {
> +        0: 'PAUSE',
> +        1: 'PROPAGATE',
> +        2: 'ATOMIC',
> +        3: 'SWEEPSTRING',
> +        4: 'SWEEP',
> +        5: 'FINALIZE',
> +        6: 'LAST',
> +    }.get(int(g['gc']['state']), 'INVALID')
> +
> +def jit_state(g):
> +    return {
> +        0:    'IDLE',
> +        0x10: 'ACTIVE',
> +        0x11: 'RECORD',
> +        0x12: 'START',
> +        0x13: 'END',
> +        0x14: 'ASM',
> +        0x15: 'ERR',
> +    }.get(int(J(g)['state']), 'INVALID')
> +
> +def tvisnumber(o):
> +    return itype(o) <= (0xfffeffff if LJ_64 and not LJ_GC64 else LJ_T['NUMX'])
> +
> +def tvislightud(o):
> +    if LJ_64 and not LJ_GC64:
> +        return (cast('int32_t', itype(o)) >> 15) == -2
> +    else:
> +        return itype(o) == LJ_T['LIGHTUD']
> +
> +def strdata(obj):
> +    # String is printed with pointer to it, thanks to gdb. Just strip it.
> +    return str(cast('char *', cast('GCstr *', obj) + 1))[len(PADDING):]
> +
> +def itypemap(o):
> +    if LJ_64 and not LJ_GC64:
> +        return LJ_T['NUMX'] if tvisnumber(o)       \
> +            else LJ_T['LIGHTUD'] if tvislightud(o) \
> +            else itype(o)
> +    else:
> +        return LJ_T['NUMX'] if tvisnumber(o) else itype(o)
> +
> +def funcproto(func):
> +    assert(func['ffid'] == 0)
> +
> +    return cast('GCproto *',
> +        mref('char *', func['pc']) - gdb.lookup_type('GCproto').sizeof)
> +
> +def gclistlen(root):
> +    count = 0
> +    while(gcref(root)):
> +        count += 1
> +        root = gcref(root)['gch']['nextgc']
> +    return count
> +
> +# Dumpers {{{
> +
> +def dump_lj_tnil(tv):
> +    return 'nil'
> +
> +def dump_lj_tfalse(tv):
> +    return 'false'
> +
> +def dump_lj_ttrue(tv):
> +    return 'true'
> +
> +def dump_lj_tlightud(tv):
> +    return 'light userdata @ {}'.format(strx64(gcval(tv['gcr'])))
> +
> +def dump_lj_tstr(tv):
> +    return 'string {body} @ {address}'.format(
> +        body = strdata(gcval(tv['gcr'])),
> +        address = strx64(gcval(tv['gcr']))
> +    )
> +
> +def dump_lj_tupval(tv):
> +    return 'upvalue @ {}'.format(strx64(gcval(tv['gcr'])))
> +
> +def dump_lj_tthread(tv):
> +    return 'thread @ {}'.format(strx64(gcval(tv['gcr'])))
> +
> +def dump_lj_tproto(tv):
> +    return 'proto @ {}'.format(strx64(gcval(tv['gcr'])))
> +
> +def dump_lj_tfunc(tv):
> +    func = cast('struct GCfuncC *', gcval(tv['gcr']))
> +    ffid = func['ffid']
> +
> +    if ffid == 0:
> +        pt = funcproto(func)
> +        return 'Lua function @ {addr}, {nupvals} upvalues, {chunk}:{line}'.format(
> +            addr = strx64(func),
> +            nupvals = int(func['nupvalues']),
> +            chunk = strdata(cast('GCstr *', gcval(pt['chunkname']))),
> +            line = pt['firstline']
> +        )
> +    elif ffid == 1:
> +        return 'C function @ {}'.format(strx64(func['f']))
> +    else:
> +        return 'fast function #{}'.format(int(ffid))
> +
> +def dump_lj_ttrace(tv):
> +    trace = cast('struct GCtrace *', gcval(tv['gcr']))
> +    return 'trace {traceno} @ {addr}'.format(
> +        traceno = strx64(trace['traceno']),
> +        addr = strx64(trace)
> +    )
> +
> +def dump_lj_tcdata(tv):
> +    return 'cdata @ {}'.format(strx64(gcval(tv['gcr'])))
> +
> +def dump_lj_ttab(tv):
> +    table = cast('GCtab *', gcval(tv['gcr']))
> +    return 'table @ {gcr} (asize: {asize}, hmask: {hmask})'.format(
> +        gcr = strx64(table),
> +        asize = table['asize'],
> +        hmask = strx64(table['hmask']),
> +    )
> +
> +def dump_lj_tudata(tv):
> +    return 'userdata @ {}'.format(strx64(gcval(tv['gcr'])))
> +
> +def dump_lj_tnumx(tv):
> +    return 'number {}'.format(cast('double', tv['n']))
> +
> +def dump_lj_invalid(tv):
> +    return 'not valid type @ {}'.format(strx64(gcval(tv['gcr'])))
> +
> +# }}}
> +
> +dumpers = {
> +    'LJ_TNIL': dump_lj_tnil,
> +    'LJ_TFALSE': dump_lj_tfalse,
> +    'LJ_TTRUE': dump_lj_ttrue,
> +    'LJ_TLIGHTUD': dump_lj_tlightud,
> +    'LJ_TSTR': dump_lj_tstr,
> +    'LJ_TUPVAL': dump_lj_tupval,
> +    'LJ_TTHREAD': dump_lj_tthread,
> +    'LJ_TPROTO': dump_lj_tproto,
> +    'LJ_TFUNC': dump_lj_tfunc,
> +    'LJ_TTRACE': dump_lj_ttrace,
> +    'LJ_TCDATA': dump_lj_tcdata,
> +    'LJ_TTAB': dump_lj_ttab,
> +    'LJ_TUDATA': dump_lj_tudata,
> +    'LJ_TNUMX': dump_lj_tnumx,
> +}
> +
> +def dump_tvalue(tvalue):
> +    return dumpers.get(typenames(itypemap(tvalue)), dump_lj_invalid)(tvalue)
> +
> +def dump_framelink(L, fr):
> +    fr2 = fr + LJ_FR2
> +
> +    return '{fr}{padding} [    ] FRAME: [{pp}] delta={d}, {f}\n'.format(
> +        fr = fr,
> +        padding = ':{fr2}'.format(fr2 = fr2) if LJ_FR2 else PADDING,
> +        pp = 'PP' if frame_ispcall(fr2) else '{frname}{p}'.format(
> +            frname = frametypes(int(frame_type(fr2))),
> +            p = 'P' if frame_typep(fr2) & FRAME_P else ''
> +        ),
> +        d = cast('TValue *', fr2) - cast('TValue *', frame_prev(fr2)),
> +        f = dump_lj_tfunc(fr),
> +    )
> +
> +def dump_stack_slot(L, slot, base=None, top=None):
> +    base = base or L['base']
> +    top = top or L['top']
> +
> +    return '{addr}{padding} [ {B}{T}{M}] VALUE: {value}\n'.format(
> +        addr = strx64(slot),
> +        padding = PADDING,
> +        B = 'B' if slot == base else ' ',
> +        T = 'T' if slot == top else ' ',
> +        M = 'M' if slot == mref('TValue *', L['maxstack']) else ' ',
> +        value = dump_tvalue(slot),
> +    )
> +
> +def dump_stack(L, base=None, top=None):
> +    base = base or L['base']
> +    top = top or L['top']
> +    maxstack = mref('TValue *', L['maxstack'])
> +    red = 5 + 2 * LJ_FR2
> +
> +    dump = '\n'.join([
> +        '{start}:{end} [    ] {n} slots: Red zone'.format(
> +             start = strx64(maxstack + 1),
> +             end = strx64(maxstack + red),
> +             n = red,
> +        ),
> +        '{maxstack}{padding} [   M]'.format(
> +            maxstack = strx64(maxstack),
> +            padding = PADDING,
> +        ),
> +        '{start}:{end} [    ] {nfreeslots} slots: Free stack slots'.format(
> +            start = strx64(top + 1),
> +            end = strx64(maxstack - 1),
> +            nfreeslots = int((tou64(maxstack) - tou64(top) - 8) >> 3),
> +        ),
> +        '{top}{padding} [  T ]'.format(
> +            top = strx64(top),
> +            padding = PADDING,
> +        )
> +    ]) + '\n'
> +
> +    slot = top - 1
> +    framelink = base - (1 + LJ_FR2)
> +
> +    while framelink > mref('TValue *', L['stack']):
> +        while slot > framelink + LJ_FR2:
> +            dump += dump_stack_slot(L, slot, base, top)
> +            slot -= 1
> +        dump += dump_framelink(L, framelink)
> +        framelink = frame_prev(framelink + LJ_FR2) - LJ_FR2
> +        slot -= 1 + LJ_FR2
> +
> +    dump += '{fr}{padding} [S   ] FRAME: dummy L'.format(
> +        fr = slot,
> +        padding = ':{nilslot}'.format(nilslot = slot + 1) if LJ_FR2 else PADDING
> +    )
> +
> +    return dump
> +
> +def dump_gc(g):
> +    gc = g['gc']
> +    stats = [ '{key}: {value}'.format(key = f, value = gc[f]) for f in (
> +        'total', 'threshold', 'debt', 'estimate', 'stepmul', 'pause'
> +    ) ]
> +
> +    stats += [ 'sweepstr: {sweepstr}/{strmask}'.format(
> +        sweepstr = gc['sweepstr'],
> +        # String hash mask (size of hash table - 1).
> +        strmask = g['strmask'] + 1,
> +    ) ]
> +
> +    stats += [ '{key}: {number} objects'.format(
> +        key = f,
> +        number = gclistlen(gc[f]),
> +    ) for f in ('root', 'gray', 'grayagain', 'weak') ]
> +
> +    # TODO: mmudata
> +
> +    return '\n'.join(map(lambda s: '\t' + s, stats))
> +
> +class LJDumpArch(gdb.Command):
> +    '''
> +lj-arch
> +
> +The command requires no args and dumps values of LJ_64 and LJ_GC64
> +compile-time flags. These values define the sizes of host and GC
> +pointers respectively.
> +    '''
> +
> +    def __init__(self):
> +        super(LJDumpArch, self).__init__(
> +            'lj-arch', gdb.COMMAND_DATA
> +        )
> +
> +    def invoke(self, arg, from_tty):
> +        gdb.write('LJ_64: {LJ_64}, LJ_GC64: {LJ_GC64}\n'.format(
> +            LJ_64 = LJ_64,
> +            LJ_GC64 = LJ_GC64
> +        ))
> +
> +LJDumpArch()
> +
> +class LJDumpTValue(gdb.Command):
> +    '''
> +lj-tv <TValue *>
> +
> +The command recieves a pointer to <tv> (TValue address) and dumps
> +the type and some info related to it.
> +
> +* LJ_TNIL: nil
> +* LJ_TFALSE: false
> +* LJ_TTRUE: true
> +* LJ_TLIGHTUD: light userdata @ <gcr>
> +* LJ_TSTR: string <string payload> @ <gcr>
> +* LJ_TUPVAL: upvalue @ <gcr>
> +* LJ_TTHREAD: thread @ <gcr>
> +* LJ_TPROTO: proto @ <gcr>
> +* LJ_TFUNC: <LFUNC|CFUNC|FFUNC>
> +  <LFUNC>: Lua function @ <gcr>, <nupvals> upvalues, <chunk:line>
> +  <CFUNC>: C function <mcode address>
> +  <FFUNC>: fast function #<ffid>
> +* LJ_TTRACE: trace <traceno> @ <gcr>
> +* LJ_TCDATA: cdata @ <gcr>
> +* LJ_TTAB: table @ <gcr> (asize: <asize>, hmask: <hmask>)
> +* LJ_TUDATA: userdata @ <gcr>
> +* LJ_TNUMX: number <numeric payload>
> +
> +Whether the type of the given address differs from the listed above, then
> +error message occurs.
> +    '''
> +
> +    def __init__(self):
> +        super(LJDumpTValue, self).__init__(
> +            'lj-tv', gdb.COMMAND_DATA
> +        )
> +
> +    def invoke(self, arg, from_tty):
> +        tv = cast('TValue *', parse_arg(arg))
> +        gdb.write('{}\n'.format(dump_tvalue(tv)))
> +
> +LJDumpTValue()
> +
> +class LJDumpString(gdb.Command):
> +    '''
> +lj-str <GCstr *>
> +
> +The command recieves a <gcr> of the corresponding GCstr object and dumps
> +the payload, size in bytes and hash.
> +
> +*Caveat*: Since Python 2 provides no native Unicode support, the payload
> +is replaced with the corresponding error when decoding fails.
> +    '''
> +
> +    def __init__(self):
> +        super(LJDumpString, self).__init__(
> +            'lj-str', gdb.COMMAND_DATA
> +        )
> +
> +    def invoke(self, arg, from_tty):
> +        string = cast('GCstr *', parse_arg(arg))
> +        gdb.write("String: {body} [{len} bytes] with hash {hash}\n".format(
> +            body = strdata(string),
> +            hash = strx64(string['hash']),
> +            len = string['len'],
> +        ))
> +
> +
> +LJDumpString()
> +
> +class LJDumpTable(gdb.Command):
> +    '''
> +lj-tab <GCtab *>
> +
> +The command recieves a GCtab adress and dumps the table contents:
> +* Metatable address whether the one is set
> +* Array part <asize> slots:
> +  <aslot ptr>: [<index>]: <tv>
> +* Hash part <hsize> nodes:
> +  <hnode ptr>: { <tv> } => { <tv> }; next = <next hnode ptr>
> +    '''
> +
> +    def __init__(self):
> +        super(LJDumpTable, self).__init__(
> +            'lj-tab', gdb.COMMAND_DATA)
> +
> +    def invoke(self, arg, from_tty):
> +        t = cast('GCtab *', parse_arg(arg))
> +        array = mref('TValue *', t['array'])
> +        nodes = mref('struct Node *', t['node'])
> +        mt = gcval(t['metatable'])
> +        capacity = {
> +            'apart': int(t['asize']),
> +            'hpart': int(t['hmask'] + 1) if t['hmask'] > 0 else 0
> +        }
> +
> +        if mt != 0:
> +            gdb.write('Metatable detected: {}\n'.format(strx64(mt)))
> +
> +        gdb.write('Array part: {} slots\n'.format(capacity['apart']))
> +        for i in range(capacity['apart']):
> +            slot = array + i
> +            gdb.write('{ptr}: [{index}]: {value}\n'.format(
> +                ptr = slot,
> +                index = i,
> +                value = dump_tvalue(slot)
> +            ))
> +
> +        gdb.write('Hash part: {} nodes\n'.format(capacity['hpart']))
> +        # See hmask comment in lj_obj.h
> +        for i in range(capacity['hpart']):
> +            node = nodes + i
> +            gdb.write('{ptr}: {{ {key} }} => {{ {val} }}; next = {n}\n'.format(
> +                ptr = node,
> +                key = dump_tvalue(node['key']),
> +                val= dump_tvalue(node['val']),
> +                n = mref('struct Node *', node['next'])
> +            ))
> +
> +LJDumpTable()
> +
> +class LJDumpStack(gdb.Command):
> +    '''
> +lj-stack [<lua_State *>]
> +
> +The command recieves a lua_State address and dumps the given Lua
> +coroutine guest stack:
> +
> +<slot ptr> [<slot attributes>] <VALUE|FRAME>
> +
> +* <slot ptr>: guest stack slot address
> +* <slot attributes>:
> +  - S: Bottom of the stack (the slot L->stack points to)
> +  - B: Base of the current guest frame (the slot L->base points to)
> +  - T: Top of the current guest frame (the slot L->top points to)
> +  - M: Last slot of the stack (the slot L->maxstack points to)
> +* <VALUE>: see help lj-tv for more info
> +* <FRAME>: framelink slot differs from the value slot: it contains info
> +  related to the function being executed within this guest frame, its
> +  type and link to the parent guest frame
> +  [<frame type>] delta=<slots in frame>, <lj-tv for LJ_TFUNC slot>
> +  - <frame type>:
> +    + L:  VM performs a call as a result of bytecode execution
> +    + C:  VM performs a call as a result of lj_vm_call
> +    + M:  VM performs a call to a metamethod as a result of bytecode
> +          execution
> +    + V:  Variable-length frame for storing arguments of a variadic
> +          function
> +    + CP: Protected C frame
> +    + PP: VM performs a call as a result of executinig pcall or xpcall
> +
> +If L is ommited the main coroutine is used.
> +    '''
> +
> +    def __init__(self):
> +        super(LJDumpStack, self).__init__(
> +            'lj-stack', gdb.COMMAND_DATA)
> +
> +    def invoke(self, arg, from_tty):
> +        gdb.write('{}\n'.format(dump_stack(L(parse_arg(arg)))))
> +
> +LJDumpStack()
> +
> +class LJState(gdb.Command):
> +    '''
> +lj-state
> +The command requires no args and dumps current VM and GC states
> +* VM state: <INTERP|C|GC|EXIT|RECORD|OPT|ASM|TRACE>
> +* GC state: <PAUSE|PROPAGATE|ATOMIC|SWEEPSTRING|SWEEP|FINALIZE|LAST>
> +* JIT state: <IDLE|ACTIVE|RECORD|START|END|ASM|ERR>
> +    '''
> +
> +    def __init__(self):
> +        super(LJState, self).__init__(
> +            'lj-state', gdb.COMMAND_DATA)
> +
> +    def invoke(self, arg, from_tty):
> +        g = G(L(None))
> +        gdb.write('{}\n'.format('\n'.join(
> +            map(lambda t: '{} state: {}'.format(*t), {
> +                'VM': vm_state(g),
> +                'GC': gc_state(g),
> +                'JIT': jit_state(g),
> +            }.items())
> +        )))
> +
> +LJState()
> +
> +class LJGC(gdb.Command):
> +    '''
> +lj-gc
> +
> +The command requires no args and dumps current GC stats:
> +* total: <total number of allocated bytes in GC area>
> +* threshold: <limit when gc step is triggered>
> +* debt: <how much GC is behind schedule>
> +* estimate: <estimate of memory actually in use>
> +* stepmul: <incremental GC step granularity>
> +* pause: <pause between successive GC cycles>
> +* sweepstr: <sweep position in string table>
> +* root: <number of all collectable objects>
> +* gray: <number of gray objects>
> +* grayagain: <number of objects for atomic traversal>
> +* weak: <number of weak tables (to be cleared)>
> +    '''
> +
> +    def __init__(self):
> +        super(LJGC, self).__init__(
> +            'lj-gc', gdb.COMMAND_DATA)
> +
> +    def invoke(self, arg, from_tty):
> +        g = G(L(None))
> +        gdb.write('GC stats: {state}\n{stats}\n'.format(
> +            state = gc_state(g),
> +            stats = dump_gc(g)
> +        ))
> +
> +LJGC()
> -- 
> 2.24.0
> 

-- 
Best regards,
IM