Offset support for special kprobe, kretprobe, tracepoint prefixes.

BCC provides trace_autoload feature where probes can be implicitly defined with the help of kprobe__, kretprobe__ prefixes. This is a great way to install the probe() without worrying much about the dirty details of various attach_XXX_probe functions. However, this method unfortunately masks off the ability to insert a probe somewhere at the middle of a function. It will be great if we can extend this mechanism to insert probe at a particular offset from the start of the function. Is there a way we can do this within the purview of C syntax ?

For eg: I was thinking of adding a '+' suffix to a probe function i.e something like below.
int kprobe____sys_socket(struct pt_regs *ctx, int f, int p, int s)+143
However, this doesn't seem like a valid C function identifier.
or
int kprobe__sys_socket(struct pt_regs *ctx, int f, int p, int s);
plausible ?

Start by locating the trace_autoload handling for kprobe__, kretprobe__, and tracepoint prefixes, then trace how probe names become attach targets. The issue does not name files or tests; done would require an agreed syntax and documented behavior for selecting an offset within a function.

Written by the indexing model from the issue text.