An old version (December 2010) of gDEBugger for Windows, Mac OS X, and Linux is still available from Gremedy.com along with information on all of the original features provided by this Israeli company.
Last week Advanced Micro Devices then released AMD gDEBugger from the AMD Developer Central area. This profiling utility is still a free download, but AMD has transformed it into being a Windows-only utility and one that plugs into Microsoft Visual Studio 2010. "AMD gDEBugger is an OpenCL and OpenGL debugger and memory analyzer integrated into Microsoft Visual Studio. gDEBugger offers real-time OpenCL kernel debugging, which allows developers to step into the kernel execution directly from the API call that issues it, debug inside the kernel, view all variable values across the different work groups and work items - and all this on a single computer with a single GPU. gDEBugger takes the mystery out of debugging OpenCL and OpenGL, allowing developers to peer into compute and graphic memory objects such as OpenCL images to view their contents as they change from write, copy, and kernel operations. Allocated OpenCL and OpenGL objects are monitored to allow detecting memory leaks and the scenarios that caused the leaking objects to be created, API function call logs can be viewed and saved and unrecommended and deprecated functions and behaviors are marked, with best-practice alternatives offered."
At a time when AMD hires new open-source employees and is continually making other improvements to their Linux support -- both open and closed-source -- it's a pity that they take a fledging cross-platform utility that's useful to many developers and transform it into a Windows-only Visual Studio plug-in.
The closest open-source equivalent to gDEBugger with support for debugging OpenGL graphics on Linux would likely be the recent release of ApiTrace.