Redirected to gcc-help. dreese@xxxxxxxxxxxxxxxxxx wrote: > Could you please direct me to someone who would be willing and able to answer a few questions about some of the internal workings of the gcc compiler. > > I am attempting to modify the compiler to instrument function calls and returns. The end result that i am trying to achieve is to send the address of every called function to a memory mapped file prior to the call and after the call send an immediate value to that same file. The target architecture is x86. > > Here is an example in pseudo assembly of what i want to accomplish. > > > regular modified > instruction instruction > instruction instruction > mov $function-name, (eax) > call function-name call function-name > move $0x1000, (eax) > instruction instruction > instruction instruction > > where eax is the address of the memory mapped file. > > > The purpose of this is to collect information about calls and returns in order to build call graphs and operating tendencies of software systems. > > So far i have had little success. > > I have been trying to change the machine description as well as the target description macros and function in order to get the desired functionality. I have been able to insert instruction into the compiled code, via output_asm_insn(), but not in the correct place. Have a look at the docs for the gcc option `-finstrument-functions'. Andrew.
