x86 assembly instruction execution count

Question

Hello everyone I have a code and I want to find the number of times each assembly line executed. I dont care whether through profiling or emulation, yet I want high precision results. I came across a forum once that gave some scripting code to do so, yet I lost the link. Can anyone help me brainstorm some ways to do so? Regards

Edit : Okey I think I am halfway there. I have done some research on the BTS (Branch Trace Store) provided by Intel Manual 3A section 16.4.5 according to one the posts. This feature provides branch history. So now I need your help to find if there are any open source scripts or tools to do this. Waiting to check your feedback

cheers=)!

Answer 1

If you do not care about performance, you can do a small trick to count that. Raise a single step exception and upon entering your custom seh handler, raise another one and step over to the next command.

Maybe some profiler tools like pin or valgrind do that for you in an easier manner. I would suggest that you take a look.

Answer 2

One (although slow) method would be to write your own debugger. It would then breakpoint the entry point of your program, and when it was hit it would set the trace flag on the EFlags in the context, so it would break to the debugger on the next instruction as well. You could then use a hash table with the EIP to count the number of times hit. Only problem is that the overhead would be extreme and the application would run very slowly.

Answer 3

If your processor supports it, you can enable Branch Trace Store (BTS). BTS stores a log of all of the taken branches in a predefined area in memory. Each entry contains the branch source and destination. Using that, you can count how many times you were in each code segment.

Look at volume 3A of the Intel Software Developer's Manual , section 16.4.5 (in the current edition) for details on how to enable it.