I ran into this today, and it's pretty frustrating:
(rr) p inner_node_
$11 = {
<cppgc::internal::MemberBase> = {
raw_ = {
static kCompressedSentinel = 1,
value_ = 2148082696
}
},
<cppgc::internal::DisabledCheckingPolicy> = {<No data fields>}, <No data
fields>}
(rr) p inner_node_.Load()
Couldn't find method blink::Member<blink::Node>::Load
(rr) p inner_node_.raw_.Load()
Cannot evaluate function -- may be inlined
(rr) p
cppgc::internal::CompressedPointer::Decompress(inner_node_.raw_.value_)
Cannot evaluate function -- may be inlined
(rr)
I found that I can avoid the issue with this in args.gn:
cppgc_enable_caged_heap = false
cppgc_enable_pointer_compression = false
... but I would prefer a better solution.
On Mon, Oct 10, 2022 at 10:22 AM Ian Kilpatrick <[email protected]>
wrote:
> Is there a bug to follow regarding the debuggability of the pointers?
>
> Ian
>
> On Thu, Sep 22, 2022 at 11:10 AM Anton Bikineev <[email protected]>
> wrote:
>
>> There is "cppgc::internal::CompressedPointer::Decompress(void*)". I
>> would, however, hide it behind a simpler name in .gdbinit.
>>
>> On Thu, Sep 22, 2022 at 5:51 PM Daniel Cheng <[email protected]> wrote:
>>
>>> Is there a callable C++ function that can turn a compressed pointer into
>>> the actual pointer value?
>>>
>>> Daniel
>>>
>>> On Thu, 22 Sept 2022 at 08:43, Anton Bikineev <[email protected]>
>>> wrote:
>>>
>>>> We have plans to provide more debugging tooling for Oilpan. I haven't
>>>> had a need to examine compressed pointers myself, however I see that some
>>>> simple gdb/windbg function that'd follow pointers would be useful.
>>>>
>>>> On Thu, Sep 22, 2022 at 1:14 AM Kentaro Hara <[email protected]>
>>>> wrote:
>>>>
>>>>> +Michael Lippautz <[email protected]>
>>>>>
>>>>> 2022年9月22日(木) 4:01 'Daniel Libby' via blink-dev <
>>>>> [email protected]>:
>>>>>
>>>>>> https://crrev.com/c/3835682 enabled pointer compression for Blink
>>>>>> Member<> pointers. How are folks handling these while debugging (either
>>>>>> live or crash dumps)? Is there some tooling available that will look up
>>>>>> and
>>>>>> apply the cage base?
>>>>>>
>>>>>> I didn't see anything mentioned in
>>>>>> https://docs.google.com/document/d/1neGN8Jq-1JLrWK3cvwRIfrSjLgE0Srjv-uq7Ze38Iao/edit#
>>>>>> but maybe there are better known tools/techniques from v8 (which IIUC has
>>>>>> had compressed pointers for some time now).
>>>>>>
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