Does it exist (even as beta)?
It seems that the last version of gDEBugger (6.2) was released 04/20/2012. It's been a while...
gDEBugger was replaced with CodeXL
However, CodeXL doesn't work on windows 8 (and perhaps visual studio 2012). Is there a solution?
CodeXL will support Windows 8 and VS2012 in its next release. AMD policy is not to disclose specific release dates. Developer Tools group will be releasing a new version of CodeXL every few months.