What's the difference between INS_AddInstrumentFunction and INS_InsertCall in Intel PIN

Question

I get confused about the two functions, I want to find out when the function passed though INS_AddInstrumentFunction will be invoked, and when the ones passed though INS_InsertCall will be invoked.

I've look though the official manual of Intel PIN but didn't find the answer

Answer 1

According to the documentation: PIN: Instrumentation API

• INS_AddInstrumentFunction: "Add a function used to instrument at instruction granularity"

• INS_InsertCall: "Insert a call to funptr relative to instruction ins."

In short, the callback argument of INS_AddInstrumentFunction gets called once for every instruction, when it is loaded by PIN.

The callback argument of INS_InsertCall gets called everytime that instruction is executed.