Re: [Tarantool-patches] [PATCH v2 luajit 3/3] gdb: enhance the extension loading

[Igor Munkin <imun@tarantool.org>]

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

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

diff --git a/src/luajit-gdb.py b/src/luajit-gdb.py
index bc37674..cccec1c 100644
--- a/src/luajit-gdb.py
+++ b/src/luajit-gdb.py
@@ -465,7 +465,9 @@ def dump_gc(g):
 class LJBase(gdb.Command):
 
     def __init__(self, name):
-        super(__class__, self).__init__(name, gdb.COMMAND_DATA)
+        # XXX Fragile: though the command initialization looks like a crap but
+        # it respects both Python 2 and Python 3.
+        gdb.Command.__init__(self, name, gdb.COMMAND_DATA)
         gdb.write('{} command initialized\n'.format(name))
 
 class LJDumpArch(LJBase):

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

On 13.02.20, Igor Munkin wrote:
> Damn the old Python:
> 
> | (gdb) source ~/luajit-gdb.py
> | Traceback (most recent call last):
> |   File "~/luajit-gdb.py", line 686, in <module>
> |   File "~/luajit-gdb.py", line 675, in load
> |   File "~/luajit-gdb.py", line 468, in __init__
> | NameError: global name '__class__' is not defined
> | (gdb) python
> | >import sys
> | >print(sys.version)
> | >2.7.5 (default, Aug  7 2019, 00:51:29) 
> | [GCC 4.8.5 20150623 (Red Hat 4.8.5-39)]
> 
> I'll fix the issue and send either diff or a new patch for this one in a
> jiffy.
> 
> On 05.02.20, Igor Munkin wrote:
> > Definition of LJ_64, LJ_GC64 and LJ_FR2 constants in script requires
> > LuaJIT internal enum values to be presented in the executable. Otherwise
> > the extension loading fails. The changes handles exception for the
> > following scenarios:
> > * luajit-gdb.py is loaded for an arbitrary executable, e.g. /bin/echo
> > * luajit-gdb.py is loaded for a luajit executable (or the one linked
> >   against libluajit) but debug info is not found
> > 
> > Signed-off-by: Igor Munkin <imun@tarantool.org>
> > ---
> >  src/luajit-gdb.py | 102 ++++++++++++++++++++--------------------------
> >  1 file changed, 45 insertions(+), 57 deletions(-)
> > 
> > diff --git a/src/luajit-gdb.py b/src/luajit-gdb.py
> > index 90df101..bc37674 100644
> > --- a/src/luajit-gdb.py
> > +++ b/src/luajit-gdb.py
> > @@ -1,3 +1,6 @@
> > +# GDB extension for LuaJIT post-mortem analysis.
> > +# To use, just put 'source <path-to-repo>/src/luajit-gdb.py' in gdb.
> > +
> >  import re
> >  import gdb
> >  import sys
> > @@ -151,11 +154,9 @@ def frame_prev(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_64 = None
> > +LJ_GC64 = None
> > +LJ_FR2 = None
> >  
> >  LJ_GCVMASK = ((1 << 47) - 1)
> >  
> > @@ -460,7 +461,14 @@ def dump_gc(g):
> >  
> >      return '\n'.join(map(lambda s: '\t' + s, stats))
> >  
> > -class LJDumpArch(gdb.Command):
> > +
> > +class LJBase(gdb.Command):
> > +
> > +    def __init__(self, name):
> > +        super(__class__, self).__init__(name, gdb.COMMAND_DATA)
> > +        gdb.write('{} command initialized\n'.format(name))
> > +
> > +class LJDumpArch(LJBase):
> >      '''
> >  lj-arch
> >  
> > @@ -469,20 +477,13 @@ 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):
> > +class LJDumpTValue(LJBase):
> >      '''
> >  lj-tv <TValue *>
> >  
> > @@ -511,18 +512,11 @@ 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):
> > +class LJDumpString(LJBase):
> >      '''
> >  lj-str <GCstr *>
> >  
> > @@ -533,11 +527,6 @@ the payload, size in bytes and hash.
> >  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(
> > @@ -546,10 +535,7 @@ is replaced with the corresponding error when decoding fails.
> >              len = string['len'],
> >          ))
> >  
> > -
> > -LJDumpString()
> > -
> > -class LJDumpTable(gdb.Command):
> > +class LJDumpTable(LJBase):
> >      '''
> >  lj-tab <GCtab *>
> >  
> > @@ -561,10 +547,6 @@ The command recieves a GCtab adress and dumps the table contents:
> >    <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'])
> > @@ -598,9 +580,7 @@ The command recieves a GCtab adress and dumps the table contents:
> >                  n = mref('struct Node *', node['next'])
> >              ))
> >  
> > -LJDumpTable()
> > -
> > -class LJDumpStack(gdb.Command):
> > +class LJDumpStack(LJBase):
> >      '''
> >  lj-stack [<lua_State *>]
> >  
> > @@ -633,16 +613,10 @@ coroutine guest stack:
> >  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):
> > +class LJState(LJBase):
> >      '''
> >  lj-state
> >  The command requires no args and dumps current VM and GC states
> > @@ -651,10 +625,6 @@ The command requires no args and dumps current VM and GC states
> >  * 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(
> > @@ -665,9 +635,7 @@ The command requires no args and dumps current VM and GC states
> >              }.items())
> >          )))
> >  
> > -LJState()
> > -
> > -class LJGC(gdb.Command):
> > +class LJGC(LJBase):
> >      '''
> >  lj-gc
> >  
> > @@ -685,10 +653,6 @@ The command requires no args and dumps current GC stats:
> >  * 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(
> > @@ -696,4 +660,28 @@ The command requires no args and dumps current GC stats:
> >              stats = dump_gc(g)
> >          ))
> >  
> > -LJGC()
> > +def load(commands):
> > +    global LJ_64, LJ_GC64, LJ_FR2
> > +
> > +    try:
> > +        LJ_64 = str(gdb.parse_and_eval('IRT_PTR')) == 'IRT_P64'
> > +        LJ_FR2 = LJ_GC64 = str(gdb.parse_and_eval('IRT_PGC')) == 'IRT_P64'
> > +    except:
> > +        gdb.write('luajit-gdb.py failed to load: '
> > +                  'no debugging symbols found for libluajit\n')
> > +        return
> > +
> > +    for name, command in commands.items():
> > +        command(name)
> > +
> > +    gdb.write('luajit-gdb.py is successfully loaded\n')
> > +
> > +load({
> > +    'lj-arch': LJDumpArch,
> > +    'lj-tv': LJDumpTValue,
> > +    'lj-str': LJDumpString,
> > +    'lj-tab': LJDumpTable,
> > +    'lj-stack': LJDumpStack,
> > +    'lj-state': LJState,
> > +    'lj-gc': LJGC,
> > +})
> > -- 
> > 2.24.0
> > 
> 
> -- 
> Best regards,
> IM

-- 
Best regards,
IM