Re: [PATCH dwarves] dwarf_loader: handle subprogram ret type with abstract_origin properly

[Arnaldo <arnaldo.melo@gmail.com>]

On April 2, 2021 2:42:21 PM GMT-03:00, Yonghong Song <yhs@fb.com> wrote:
>On 4/2/21 10:23 AM, Yonghong Song wrote:
:> Thanks. I checked out the branch and did some testing with latest
>clang 
>> trunk (just pulled in).
>> 
>> With kernel LTO note support, I tested gcc non-lto, and llvm-lto
>mode, 
>> it works fine.
>> 
>> Without kernel LTO note support, I tested
>>    gcc non-lto  <=== ok
>>    llvm non-lto  <=== not ok
>>    llvm lto     <=== ok
>> 
>> Surprisingly llvm non-lto vmlinux had the same "tcp_slow_start"
>issue.
>> Some previous version of clang does not have this issue.
>> I double checked the dwarfdump and it is indeed has the same reason
>> for lto vmlinux. I checked abbrev section and there is no cross-cu
>> references.
>> 
>> That means we need to adapt this patch
>>    dwarf_loader: Handle subprogram ret type with abstract_origin
>properly
>> for non merging case as well.
>> The previous patch fixed lto subprogram abstract_origin issue,
>> I will submit a followup patch for this.
>
>Actually, the change is pretty simple,
>
>diff --git a/dwarf_loader.c b/dwarf_loader.c
>index 5dea837..82d7131 100644
>--- a/dwarf_loader.c
>+++ b/dwarf_loader.c
>@@ -2323,7 +2323,11 @@ static int die__process_and_recode(Dwarf_Die 
>*die, struct cu *cu)
>         int ret = die__process(die, cu);
>         if (ret != 0)
>                 return ret;
>-       return cu__recode_dwarf_types(cu);
>+       ret = cu__recode_dwarf_types(cu);
>+       if (ret != 0)
>+               return ret;
>+
>+       return cu__resolve_func_ret_types(cu);
>  }
>
>Arnaldo, do you just want to fold into previous patches, or
>you want me to submit a new one?

I can take care of that.

And I think it's time for to look at Jiri's test suite... :-)

It's a holiday here, so I'll take some time to get to this, hopefully I'll tag 1.21 tomorrow tho.

Cheers,

- Arnaldo 

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