> I need to review my own code
I recommend to start by taking a look at _array function which
returned Array in question.
> Why did Length() method fail to detect IsDeadCheck()?
IsDeadCheck checks whether VM is dead, not whether the object itself
is dead. There is no way to detect whether a given object is valid or
it died because his space can be already reused for something else.
--
Vyacheslav Egorov
On Fri, Apr 22, 2011 at 5:44 PM, <rchar...@speakeasy.net> wrote:
>
> Thanks Vyacheslav,
>
> Thing #1: I do agree with you, I need to review my own code and track my
> objects better and not try to ask for Length() on a dead object. Bummer.
>
> Thing #2: Why did Length() method fail to detect IsDeadCheck()? It seems
> that my `this` pointer is a corrupted form of kZapValue. I have
> this=0xdeadbeedbeadbe05
> instead of deadbeeddeadbeed. I think the poignant question here is, "who
> corrupted my kZapValue?". But that is probably very difficult to answer.
> Bummer^2.
>
> --
> Ricky Charlet
> See Y' Later
>
> On Fri Apr 22 7:53 , Vyacheslav Egorov sent:
>
>>Hi Ricky,
>>
>>Yeah, that looks like a dead object.
>>
>>I would suspect a Handle-misuse somewhere. However it is hard to
>>diagnose. You need to look through your code and check that you have
>>HandleScopes in proper places, that you use Persistent handles where
>>appropriate and does not simply return Local handles without properly
>>closing containing HandleScope.
>>
>>--
>>Vyacheslav Egorov
>>
>>
>>
>>On Thu, Apr 21, 2011 at 8:04 PM, Ricky Charlet rchar...@speakeasy.net> wrote:
>>> BTW,
>>> This is trunk code from 4/21.
>>>
>>> On Apr 21, 10:51 am, Ricky Charlet rchar...@speakeasy.net> wrote:
>>>> Howdy,
>>>> I'm new to v8. However my company has been using v8 since 1.3.
>>>> I've got the task to investigate modernizing it. So I've got two
>>>> variables in play here... I'm changing from v8-1.3 to v8-3.3.1 and
>>>> also changing from a 32bit architecture to a 64 bit architecture. I'm
>>>> suspecting the 64 bit change is causing my crash for the modest reason
>>>> that there are so many casts in my path to the crash.
>>>>
>>>> OK, So I have v8-3.3.1 complied with
>>>> `scons arch=x64 arch_size=64 mode=debug` and I've statically linked my
>>>> code to libv8_g.a (renamed to libv8.a).
>>>>
>>>> My program is calling v8::Array::Length in api.cc. I guess I'm
>>>> calling length on a dead object because of the "deadbee..." in
>>>> "#1 0x00000000006034e0 in v8::internal::HeapObject::map
>>>> (this=0xdeadbeedbeadbe05) at src/objects-inl.h:1176"
>>>>
>>>> I've noticed many casts up and down the frame0 through frame5 stuff.
>>>> That may or may not be germane to the issue and I did not ponder them
>>>> very deeply before I just ran to this list to see if anyone else wants
>>>> to chime in with some experience and wisdom here.
>>>>
>>>> Here is my gdb stack trace.
>>>>
>>>> Program received signal SIGSEGV, Segmentation fault.
>>>> 0x0000000000603536 in v8::internal::HeapObject::map_word
>>>> (this=0xdeadbeedbeadbe05)
>>>> at src/objects-inl.h:1186
>>>> 1186 return MapWord(reinterpret_cast(READ_FIELD(this,
>>>> kMapOffset)));
>>>> (gdb) bt
>>>> #0 0x0000000000603536 in v8::internal::HeapObject::map_word (
>>>> this=0xdeadbeedbeadbe05) at src/objects-inl.h:1186
>>>> #1 0x00000000006034e0 in v8::internal::HeapObject::map
>>>> (this=0xdeadbeedbeadbe05)
>>>> at src/objects-inl.h:1176
>>>> #2 0x000000000060224a in v8::internal::Object::IsHeapNumber() ()
>>>> #3 0x00000000006026ae in v8::internal::Object::IsNumber() ()
>>>> #4 0x00000000006031f6 in v8::internal::Object::Number() ()
>>>> #5 0x00000000005fac84 in v8::Array::Length (this=0x147ded8) at src/
>>>> api.cc:4297
>>>> #6 0x00000000004566c5 in mus_parser::_create_step
>>>> (this=0x7fffffffdff0, obj=...)
>>>> at ../../mus_parser_gen.cc:2840
>>>> #7 0x000000000043f9d2 in mus_parser::_create_scenario
>>>> (this=0x7fffffffdff0, obj=...)
>>>> at ../../mus_parser.cc:276
>>>> #8 0x0000000000442764 in mus_parser::load (this=0x7fffffffdff0,
>>>> musl=...)
>>>> at ../../mus_parser.cc:681
>>>> #9 0x0000000000480ea6 in mus_test_builder::make_scenario
>>>> (this=0x7fffffffe990,
>>>> scheduler=0x7fffffffe820, obj=..., error=...) at ../../
>>>> mus_test_builder.cc:200
>>>> #10 0x000000000048014d in mus_test_builder::make_track
>>>> (this=0x7fffffffe990,
>>>> scheduler=0x7fffffffe820, obj=..., error=...) at ../../
>>>> mus_test_builder.cc:141
>>>> #11 0x000000000047ff1f in mus_test_builder::build_test_internal (
>>>> this=0x7fffffffe990, scheduler=0x7fffffffe820, json=...,
>>>> error=...)
>>>> at ../../mus_test_builder.cc:125
>>>> #12 0x000000000047fb8e in mus_test_builder::build_test
>>>> (this=0x7fffffffe990,
>>>> scheduler=0x7fffffffe820, json=..., error=...) at ../../
>>>> mus_test_builder.cc:73
>>>> #13 0x000000000040e3a5 in execute_json (opts=...) at ../../testr.cc:
>>>> 552
>>>> #14 0x000000000040e816 in main (argc=0, argv=0x7fffffffec70) at ../../
>>>> testr.cc:621
>>>> (gdb) list
>>>> 1181 set_map_word(MapWord::FromMap(value));
>>>> 1182 }
>>>> 1183
>>>> 1184
>>>> 1185 MapWord HeapObject::map_word() {
>>>> 1186 return MapWord(reinterpret_cast(READ_FIELD(this,
>>>> kMapOffset)));
>>>> 1187 }
>>>> 1188
>>>> 1189
>>>> 1190 void HeapObject::set_map_word(MapWord map_word) {
>>>> (gdb) :q
>>>> Undefined command: "". Try "help".
>>>> (gdb) frame 6
>>>> #6 0x00000000004566c5 in mus_parser::_create_step
>>>> (this=0x7fffffffdff0, obj=...)
>>>> at ../../mus_parser_gen.cc:2840
>>>> 2840 for (uint32_t n=0; nLength(); ++n) {
>>>> (gdb) l
>>>> 2835 if (v_payload == 0) goto bummer;
>>>> 2836 v->payload(v_payload);
>>>> 2837 }
>>>> 2838
>>>> 2839 Handle variables = _array(obj, "variables");
>>>> 2840 for (uint32_t n=0; nLength(); ++n) {
>>>> 2841 Handle variable_obj = _object(variables, n);
>>>> 2842 mus_step_variable *variable = _create_variable(v,
>>>> variable_obj);
>>>> 2843 if (variable == 0) goto bummer;
>>>> 2844 v->variables(variable);
>>>>
>>>> Hopefully,
>>>> Ricky Charlet
>>>
>>> --
>>> v8-users mailing list
>>> v8-users@googlegroups.com
>>> http://groups.google.com/group/v8-users
>>>
>>
>>--
>>v8-users mailing list
>>v8-users@googlegroups.com
>>http://groups.google.com/group/v8-users
>
>
>
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