Re: Build src tree in Develop/Debug mode

In reply to: Farhan Khan: "Build src tree in Develop/Debug mode"
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From: Zhenlei Huang <zlei_at_FreeBSD.org>
Date: Thu, 07 Dec 2023 02:17:14 UTC


> On Dec 7, 2023, at 1:09 AM, Farhan Khan <farhan@farhan.codes> wrote:
> 
> Hi all,
> 
> Is there a build-in-debug-mode flag I can run when building the kernel (or world)?
> 
> I was tinkering through the build system and saw that the optimization is hardcoded to -O2 and objcopy strips debugging symbols. This means even with "CFLAGS+=-g -O0 -fno-inline-functions" in my /etc/make.conf I am still losing symbols and sometimes getting unwanted optimizations. The result is that `kgdb` often does not know what line a crash took place in.
> 
> Is there an option to disable all optimizations, optimizations and symbol stripping? If not, IMO, this would be a good candidate for an option to add.

There's an option COPTFLAGS. You can try 

```
$ setenv COPTFLAGS -O0
$ make buildkernel KERNCONF=GENERIC
```

> 
> I briefly wrote about this a few years back: https://blog.farhan.codes/2018/08/16/including-optimized-out-kernel-symbols-in-dtrace-on-freebsd/
> 
> Thanks!
> --
> Farhan Khan
> PGP Fingerprint: 1312 89CE 663E 1EB2 179C 1C83 C41D 2281 F8DA C0DE
> 
> 

Best regards,
Zhenlei