Getting started with clang debuginfo

[Paul Floyd]

> On 27 Jul 2020, at 16:37, Mark Johnston <markj at freebsd.org> wrote:
> 
> On Mon, Jul 27, 2020 at 11:27:40AM +0200, Paul FLOYD wrote:
>> Hi
>>  
>> I'm investigating some of the remaining issues with Valgrind on FreeBSD. One of the two remaining major issues that I'm aware of is with Valgrind reading dwarf  debuginfo from clang compiled binaries. The problem isn't too bad with clang 8 on FreeBSD 12.1. On 13-CURRENT with clang 10 things are noticeably worse. For GCC built binaries I'm not aware of any issues.
>>  
>> I'm not familiar (yet) with the debuginfo code in Valgrind.
>>  
>> To get me going, does anyone have any pointers to
>> - documentation on clang debuginfo
>> - any info on differences wrt GCC (I have seen that GCC does have some debuginfo extensions)
>> - any tools that would be useful like ascii dumps
> 
> Are you asking about tools to dump DWARF info?  I've used dwarfdump
> (from ports) quite a bit in the past.  readelf -w is similar and
> available in the base system.

Hi Mark

Yes, I’m trying to start working out where there are differences

Clang 8 vs clang 10 vs just about any GCC

I’d already seen readelf, but I hadn’t installed dwarfdump.

I just had a look at one example, there’s a bit less info in the clang generated file, but otherwise it looks OK.

Next I’ll try comparing a problem clang 10 binary with a clang 8 one.

A+
Paul