GDB Emacs hangs after running any binary

1
votes

I am trying to set up Emacs and GDB such that I can have the gdb-many-windows option running. However, m-x gdb hangs after running any binary, and Emacs starts consuming 100% CPU and becomes unresponsive.

I am running on:

Here's what happens:

I run some binary with m-x gdb and then 'gdb --i=mi [name of binary]'. Everything works fine, the correct windows set up and everything. I then give the command 'run' to GDB, and it runs the code correctly. But once the code finishes, Emacs becomes unresponsive and start consuming 100% CPU power. This happens even with a simple hello world program. I have tried giving various options like --annotate=3, --fullname etc.

If I instead run m-x gud-gdb, I can run the same binary just fine, gdb exits normally and I can continue using Emacs.

Any help would be much appreciated.

1
emacsgdb

1 Answers

3
votes

The bug is confirmed in my mac. What's more, emacs with the same configuration (actually no configuration at all) works well in my Linux machines. So it is a bug related to Mac OS X.

Update:

  • It seems that some modes/plugins in emacs which conflicts with "gdb". When I run it without loading anything in .emacs, it stops hanging emacs when gdb debug finished. I will try to track which mode causes such problems, and report it here.
  • It seems that many modes could lead to freezing emacs when gdb finishes debugging, e.g. "helm" and any modes using helm, "function-args" (which enables some features of helm in its source codes)
  • To my configuration, dozens of modes enable, helm is the critical mode that cause gdb to freeze emacs when it reaches the end.
  • It's not due to helm, but due to semantic-mode, which might be enabled when you want to use helm-semantic-or-imenu.

Conclusions:

It is caused by semantic-mode, which performs poorly in Mac OS X, even its basic functionality has bugs. Under Linux, it doesn't have any obvious issues, that's why gdb works in Linux. Search around your .emacs and make sure disable all semantic-mode, then it should work.

Note that, even though you disabled semantic-mode before run gdb, if semantic-mode is initially enabled, it will still freeze emacs. semantic-mode has be initially disabled.

Thanks to thierryvolpiatto for help in debugging: https://github.com/emacs-helm/helm/issues/1168#issuecomment-140132443