I thought I’d provide some updates on a few things my team has been doing on debugging tools.
Just today Carlos Seo committed a patch to GDB adding support for writing AltiVec (PowerPC’s SIMD instructions) registers to corefiles when using the gcore (or generate-core-file) command. This support will show up, then, in the next GDB release. He also had a patch committed last year, in time for GDB 6.8 release, adding support for reading AltiVec registers from core files generated by the Linux kernel, starting from version 2.6.24 (kernel patch provided by Mark Nelson).
Luis Machado posted in February a patch for ltrace which fixed a number of ABI-related bugs for PowerPC 32-bits and 64-bits. The patch was committed in March. The ltrace maintainer has been out for quite a while now, so I don’t think this will appear in an official release any time soon, but it will surely be picked up by the distros.
Going back to GDB, Luis implemented displaced instruction stepping for PowerPC, helping a bit with the non-stop multithread debugging effort carried out by CodeSourcery. The patch didn’t go in yet, it’s awaiting review. He’s also been monitoring the non-stop patches and testing them on PowerPC, having already provided some feedback and pointed out a few regressions.