RFR(S) 8193318: ELF decoder should be able to use external debug info file

[yumin qi]

>From design, SA do not share code with hotspot, it use vmstruct to get
hotspot internal data structures. Sharing files between the two is not a
good idea.

On Fri, Mar 2, 2018 at 5:13 AM, Zhengyu Gu <zgu at redhat.com> wrote:

> Hi Yumin,
>
> Thanks for the suggestion.
>
> I am not sure that it is wroth the trouble to introduce such dependency.
>
> Although, the code is similar (except gnu_debuglink_crc32()), it actually
> can *not* be shared, due to two different memory allocation mechanism
> (os::malloc vs. ::malloc, etc.)
>
>
> -Zhengyu
>
>
> On 03/01/2018 08:33 PM, yumin qi wrote:
>
>> I think the way to do it is share .[h]pp and include .[c]pp in both make
>> files.
>> That is, in SA, where you use decode, include the head for it. Remove
>> decode from SA. You need be careful for the change.
>>
>> Yumin
>>
>> On Thu, Mar 1, 2018 at 7:26 AM, Zhengyu Gu <zgu at redhat.com <mailto:
>> zgu at redhat.com>> wrote:
>>
>>     Hi Andrew,
>>
>>     On 03/01/2018 04:03 AM, Andrew Haley wrote:
>>
>>         On 23/02/18 17:01, Aleksey Shipilev wrote:
>>
>>             *) I am wondering if we can merge the existing implementation
>> in
>>             src/jdk.hotspot.agent/linux/native/libsaproc/symtab.c and
>>             this mirror implementation in
>>             src/hotspot/os/linux/decoder_linux.cpp? Notably, moving
>>             gnu_debuglink_crc32 to some shared file
>>             would trim down the change.
>>
>>             Andrew Haley knows this better, as he is the author of the
>>             related change.
>>
>>
>>         It would be nice not to have to repeat all this stuff.
>>
>>     Agree. However, I am not aware a way to share code between agent and
>>     hotspot.
>>
>>     Any suggestions?
>>
>>     Thanks,
>>
>>     -Zhengyu
>>
>>
>>