Debugger showing strange values/errors

[goclipse]

Debugger showing strange values/errors

[bruno-medeiros]

Compiling with optimizations disabled might improve things. From http://golang.org/doc/gdb :

These optimizations can sometimes make debugging with gdb harder. To disable them when debugging, pass the flags -gcflags "-N -l" to the go command used to build the code being debugged.

Unfortunately there is no way yet to add this extra options to the Go build performed from Eclipse. (I want to get that done for the next release). You can try building the executable from the command-line, and then debugging it from Eclipse (place the executable somewhere in the GoClipse project, then right-click and do "Debug As").

Also, what is your platform? Is it Windows? That could be another problem because debug output support in Windows seems buggier than in Linux (this is a problem with the Go toolchain itself, not GoClipse)

[bruno-medeiros]

Also, what is the full output of the gdb console in Eclipse? (not the gdb traces console)

[panmari]

Unfortunately there is no way yet to add this extra options to the Go build performed from Eclipse. (I want to get that done for the next release). You can try building the executable from the command-line, and then debugging it from Eclipse (place the executable somewhere in the GoClipse project, then right-click and do "Debug As").

Just tried that after compiling it with -gcflags "-N -l" y hand, did not change the result. For testing I replaced the existing bin/main executable before debugging (it was not compiled newly before debugging, I checked with md5sum)

Also, what is your platform?

I'm on Linux x64

Also, what is the full output of the gdb console in Eclipse?

warning: Missing auto-load scripts referenced in section .debug_gdb_scripts
of file /home/panmari/go_workspace/gort/bin/main
Use `info auto-load python-scripts [REGEXP]' to list them.
The target endianness is set automatically (currently little endian)

[panmari]

And if I list the python-scripts

info auto-load python-scripts
Loaded  Script                                                                 
No      /usr/local/go/src/pkg/runtime/runtime-gdb.py 

[panmari]

On the golang gdb page they state

To help GDB find the Go runtime sources and the accompanying support script, pass your $GOROOT with the '-d' flag

Can I add such arguments in Debug Configuration > Debugger > GDB Debugger ? Doesn't seem to work for me, though.

By making a symlink from /usr/local/go to /opt/go and adding

 add-auto-load-safe-path /

to the .gdbinit in the project home, I could get rid of the error in gdb. It now says

Loading Go Runtime support.
The target endianness is set automatically (currently little endian)

But the issue mentioned in the initial comment still remains.

[bruno-medeiros]

I was about to point you to the thread detailing how to deal with loading the Go debugging runtime ( https://groups.google.com/forum/#!topic/goclipse/ce8vJn3KU9s ) but it seems you got there already.

If the initial problems remains, I need more info. Can you post a minimal Go source that reproduces the problem? Also, what is your GDB version?

[panmari]

Hmmm, I'll try to find one.
I'm using the default gdb from the repositories of Ubuntu 14.04:

GNU gdb (Ubuntu 7.7-0ubuntu3.1) 7.7

[panmari]

Even this little example

package main

import (
    "fmt"
)

func main() {
    a := "Test"
    fmt.Println(a)
}

Can not show debugging informations when stoped on fmt.Println(a), see screenshot attached:

I used golang 1.3.1, gdb 7.7, eclipse luna for generating this. I compiled the binary through the console with debugging flags (-gcflags "-N -l") and made sure gdb had go runtim support using the configuration mentioned above.

[bruno-medeiros]

Can you try again the example above with the latest Goclipse (0.8.1) ? If the problem persists, please attach the full contents of the "gdb traces" console, and the normal "gdb" console. (You can use https://gist.github.com/ to upload attachments)

[panmari]

Nope, still the same behavior. See gdb output

https://gist.github.com/panmari/aecbc7395b77d4095f8f

and gdb traces

https://gist.github.com/panmari/bad22281ed0b31beb68c

[csterryliu]

I also have the same issue. My platform is Windows 7 64-bit. The problem is I get weird values in the Variable window. I cannot do debugging in the situation like this. Please help.
I use the latest version of Goclipse. IDE is Eclipse Luna. GDB version 7.8 (64-bit). And GO language (64-bit).

[sunshineo]

I am on Mac and GDB 7.8
A lot of variables shows up empty

[bruno-medeiros]

@csterryliu I'm afraid variable inspection doesn't work on Windows. This is a limitation of the Go toolchain, not Goclipse. I've added that info the UserGuide though.

[bruno-medeiros]

@sunshineo That looks like it might be a different issue. Please take a look at
https://github.com/GoClipse/goclipse/blob/latest/documentation/ReportIssue.md#debugger-issues and if the problem persists open a new issue.

[bruno-medeiros]

@panmari I just tried that basic hello world with a local variable in Lubuntu, with the command-line GDB, and the display of local vars didn't work either... They either are missing or show garbage values. So, this seems to indicate it's a go toolchain problem. I'd like to investigate this further though, check in with the Go user group.

[lopperma]

@bruno-medeiros the faulty display of variables is also mentioned here: https://code.google.com/p/go/issues/detail?can=2&start=0&num=100&q=&colspec=ID%20Status%20Stars%20Release%20Owner%20Repo%20Summary&groupby=&sort=&id=8256

I'm having the same issue on Mac. Basically, debugging seems to generally broken in a way that is not GoClipse related.

I'll check how far I get with a gccgo based build...

[bruno-medeiros]

The Go issue is now at: golang/go#8256
We'll keep an eye on that issue to see if the debugging situation improves.
In the meanwhile, if someone could experiment with gccgo to see if the debug support there is better, that would be helpful.

[lopperma]

I've had quite a hard time getting the full toolchain to work with gccgo on Mac. I've gotten to a point where the compiler seems to work but I still don't get all dependencies/packages of projects to be linked correctly. I'll keep trying it a bit more but I cannot currently allocate a lot of time to this effort...