Debugging a program built with tup

[Tomek Sowiński]

My setup is following "A First Tupfile" tutorial with the Tupfile changed like this:

: hello.c |> clang -Og -g hello.c -o hello |> hello

This compiles but the debug paths are wrong:

$ symbols -fullSourcePath hello | grep hello.c
                    0x0000000000000000 (     0x4) /Users/tomek/Desktop/prj/tuptest/.tup/mnt/@tupjob-11/Users/tomek/Desktop/prj/tuptest/hello.c:4
                    0x0000000000000004 (     0xc) /Users/tomek/Desktop/prj/tuptest/.tup/mnt/@tupjob-11/Users/tomek/Desktop/prj/tuptest/hello.c:5
                    0x0000000000000010 (     0x4) /Users/tomek/Desktop/prj/tuptest/.tup/mnt/@tupjob-11/Users/tomek/Desktop/prj/tuptest/hello.c:6

I understand the `.tup/mnt/@tupjob-<id>/...` part is for a FUSE filesystem mount to transparently track dependencies. But why doesn't it chdir() into `.../.tup/mnt/@tupjob-11/Users/tomek/Desktop/prj/tuptest/` and run clang with the relative path from there? If it does chdir() into it, why does it embed the FUSE mount path?

Having DAFS, I found out a way to solve this problem is to tack ^c^ in front of the command to run it inside a chroot. OK.

tup error: This process requires namespacing, but this kernel does not support namespacing and tup is not privileged. You'll need to upgrade your kernel, or compile tup with CONFIG_TUP_SUDO_SUID=y in order to support the ^c flag.

Creating a tup.config file with `CONFIG_TUP_SUDO_SUID=y` doesn't help. Tup updated the variant but failed with the same message.

Running a privileged tup crapped out differently:

$ sudo tup
Password:
[ tup ] [0.000s] Scanning filesystem...
[ tup ] [0.001s] Reading in new environment variables...
[ tup ] [0.001s] No Tupfiles to parse.
[ tup ] [0.001s] No files to delete.
[ tup ] [0.001s] Executing Commands...
* 0) clang -Og -g hello.c -o hello                                                                                                                  
clang: error: couldn't rename cache file '/var/folders/zz/zyxvpxvq6csfxvn_n0000000000000/T/xcrun_db-AY8QHbSY' to '/var/folders/zz/zyxvpxvq6csfxvn_n0000000000000/T/xcrun_db' (errno=No such file or directory)
 *** tup messages ***
tup error: File '/private/var/folders/zz/zyxvpxvq6csfxvn_n0000000000000/T/xcrun_db-AY8QHbSY' was written to, but is not in .tup/db. You probably should specify it as an output
 *** Command failed due to errors processing the output dependencies.
 [ ] 100%
 *** tup: 1 job failed.

I can of course set `target.source-map` in lldb to strip the FUSE prefix post-build but I presume the @tupjob-<id> is related to parallelisation and therefore <id> is not fixed. Another idea of mine was to add `--fdebug-prefix-map` to the clang command to strip it during build but what should I put there? Is there a $(TUP_variable) with the real current dir containing the FUSE mount or do I really need to call `pwd` each time I run clang? Either way sounds like overdoing things... So instead of fighting uphill, I figured the people out there must know a less ridiculous way to do something as basic as stepping through a program.

So, how do you debug a program built with tup?

I'm on macOS 10.15.1, FUSE 3.10.3, tup v0.7.8 (although it doesn't tell that).

Regards,

Tomek

[Jose Quinteiro]

Unfortunately, the ^c^ workaround does not work on Mac:

https://github.com/gittup/tup/issues/225#issuecomment-443458928

Thanks,
Jose

On 11/14/19 10:03 AM, Tomek Sowiński wrote:
> My setup is following "A First Tupfile" tutorial with the Tupfile
> changed like this:
>
> |

> :hello.c |>clang -Og-g hello.c -o hello |>hello

> |
>
> This compiles but the debug paths are wrong:
>
> |
> $ symbols -fullSourcePath hello |grep hello.c
> 0x0000000000000000(0x4)/Users/tomek/Desktop/prj/tuptest/.tup/mnt/@tupjob-11/Users/tomek/Desktop/prj/tuptest/hello.c:4
> 0x0000000000000004(0xc)/Users/tomek/Desktop/prj/tuptest/.tup/mnt/@tupjob-11/Users/tomek/Desktop/prj/tuptest/hello.c:5

> 0x0000000000000010(0x4)/Users/tomek/Desktop/prj/tuptest/.tup/mnt/@tupjob-11/Users/tomek/Desktop/prj/tuptest/hello.c:6

> |
>
> I understand the `.tup/mnt/@tupjob-<id>/...` part is for a FUSE
> filesystem mount to transparently track dependencies. But why doesn't it
> chdir() into `.../.tup/mnt/@tupjob-11/Users/tomek/Desktop/prj/tuptest/`
> and run clang with the relative path from there? If it does chdir() into
> it, why does it embed the FUSE mount path?
>
> Having DAFS, I found out a way to solve this problem is to tack ^c^ in
> front of the command to run it inside a chroot. OK.
>
> |
> tup error:Thisprocess requires namespacing,but thiskernel does

> notsupport namespacing andtup isnotprivileged.You'll need to upgrade

> your kernel, or compile tup with CONFIG_TUP_SUDO_SUID=y in order to
> support the ^c flag.
> |
>
> Creating a tup.config file with `CONFIG_TUP_SUDO_SUID=y` doesn't help.
> Tup updated the variant but failed with the same message.
>
> Running a privileged tup crapped out differently:
>
> |
> $ sudo tup
> Password:
> [tup ][0.000s]Scanningfilesystem...
> [tup ][0.001s]Readinginnewenvironment variables...
> [tup ][0.001s]NoTupfilesto parse.
> [tup ][0.001s]Nofiles to delete.
> [tup ][0.001s]ExecutingCommands...

> *0)clang -Og-g hello.c -o hello

> clang:error:couldn't rename cache file
> '/var/folders/zz/zyxvpxvq6csfxvn_n0000000000000/T/xcrun_db-AY8QHbSY' to
> '/var/folders/zz/zyxvpxvq6csfxvn_n0000000000000/T/xcrun_db' (errno=No
> such file or directory)
>  *** tup messages ***
> tup error: File
> '/private/var/folders/zz/zyxvpxvq6csfxvn_n0000000000000/T/xcrun_db-AY8QHbSY'
> was written to, but is not in .tup/db. You probably should specify it as
> an output
>  *** Command failed due to errors processing the output dependencies.
>  [ ] 100%
>  *** tup: 1 job failed.
> |
>
> I can of course set `target.source-map` in lldb to strip the FUSE prefix
> post-build but I presume the @tupjob-<id> is related to parallelisation
> and therefore <id> is not fixed. Another idea of mine was to add
> `--fdebug-prefix-map` to the clang command to strip it during build but
> what should I put there? Is there a $(TUP_variable) with the real
> current dir containing the FUSE mount or do I really need to call `pwd`
> each time I run clang? Either way sounds like overdoing things... So
> instead of fighting uphill, I figured the people out there must know a
> less ridiculous way to do something as basic as stepping through a program.
>
> So, how do you debug a program built with tup?
>
> I'm on macOS 10.15.1, FUSE 3.10.3, tup v0.7.8 (although it doesn't tell

> that <https://github.com/gittup/tup/issues/384>).
>
> Regards,
> Tomek
>
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