edb-debugger
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eteran
Run Until Return is very slow
For a function with a long loop, Run Until Return appears too slow to be usable. At least one part of it seems to be the DebuggerCore::get_state() calls. Since the only thing which is used there is instruction pointer, it should take some shortcut: at least not query the extended states like SSE/AVX/etc., and at best use PTRACE_P{EEK,OKE}_USER.
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Actually this is very similar to #263, but is another case to check when it's fixed.
Yea, I imagine that it's two sides of the same coin. perhaps we should introduce a version of get_state that specifically only fills GPRs or something like that to make these type of operations faster?
Hmm, I think this should first be benchmarked. I guess peek/poke would be still faster.
Yea, peek/poke would definitely be faster for simply running until EIP is at a location that disassembles to a ret. The difficulty is in trying to also support things like expression evaluation efficiently as well.
For the special case of "Run until return", we may be able to get away with a very minimalist/fast approach.
Perhaps we could add to the thread API some sort of "PeekRegister" function that lets you directly ask for a specific register so things like this can be done cheaply.
But specific register would mean comparison of strings I guess? That doesn't look too performant... For common things like instruction pointer I think special functions should be available. And for something more rarely used maybe a state cache would be a good idea.