On Sun, Jul 18, 2010 at 12:24:00PM -0700, Eliot Miranda wrote:

<snip>

In Cog platforms/unix/vm/sqUnixMain.c you'll find code to cause SIGUSR1 to print all stacks. This can easily be ported to the standard VM. Is the above with Cog or the standard VM?

It would be best not to tie printAllStacks() to a specific signal, because SIGUSR1 is often used by third-party libraries that may be embedded in plugins or called through FFI. Perhaps it could be to enabled via a command line option if it is going to be part of the VM proper.

But the feature also seemed like a reasonable fit for OSProcessPlugin, so I added it to OSPP and OSProcess (SqueakSource latest versions). OSPP already had a mechanism for forwarding arbitrary unix signals to Smalltalk semaphores, so the printAllStacks() hook is embedded into that framework. The updates are:

OSProcessPlugin 4.3.4

Add #primitivePrintAllStacksOnSignal to attach the printAllStacks() interpreter debugging function to a unix signal. Intended for debugging support to enable SIGUSR1 to trigger a stack trace on console output.

OSProcess 4.3.13

Implement debugging stack dump methods: UnixOSProcessAccessor>>setPrintAllStacksOnSigUsr1 UnixOSProcessAccessor>>clearPrintAllStacksOnSigUsr1 UnixOSProcessAccessor>>primPrintAllStacksOnSignal:

To enable printAllStacks() on receipt of a SIGUSR1 signal: OSProcess accessor setPrintAllStacksOnSigUsr1

To disable printAllStacks() and restore the default SIGUSR1 handler: OSProcess accessor clearPrintAllStacksOnSigUsr1

Dave