trace of instructions of a C program

[jesusitoLinux]

HI Friends!

I would like to know if there is a tool to know the trace of instructions of a program once it has finished. I know I can debug with gdb as the program is executing, but I am using ncurses and it is very difficult.

Thank you very much!

[Cabhan]

It depends on what you mean by "trace of instructions".

You can have your programs produce a core dump file if they crash, and feed this into gdb to see what their state was when they crashed.

If you're only interested in system calls, you can use strace to get a log of all the system calls made by a program.

[jesusitoLinux]

HI Cabhan! Thanks for reply.

I am not interested in system calls. I want to know the trace of instructions of a C program, once it has finished, regardless the program crashes or not.

Maybe there is a way to save the executed instructions in a file, but I don't know how to do it.

Thank you very much!!!

[pieman]

Do you mean you want to produce log information to show what functions have been called and it what order etc.? If so, you probably want to look at syslog.

For more info, look at "man 3 syslog"

[Rubberman]

This is not a built-in C/C++ programming feature. You have to create/utilize appropriate trace functions/macros yourself. I have done this for major software systems that run most of the semi-conductor fabs in the world. You want to enable different levels of tracing, depending upon the situation (too high a level will seriously impact performance), by seeing a system variable at runtime. If you are using C++, then you can add the appropriate macro at the entrance to a function for the enter-trace, and when the function exits, scoping will cause the exit-trace to be emitted as necessary. This is very useful for complex systems, but unfortunately there are no standards for this behavior... It is a "do it as you need" scenario...

[drl]

Hi.

... I am not interested in system calls. I want to know the trace of instructions of a C program, once it has finished, regardless the program crashes or not ...

Just so we understand, you run the executable from a C code, and for every instruction that is executed in user-space, you want that instruction written to a disk file, is that correct?

You don't want any register data, just the instruction.

I think the only way to do this is with an emulator, which will essentially interpret the code, and write data to your trace file as it happens.

Right off-hand, that sounds like a very long disk file will be created, and the execution will be very slow. I suppose there might be some hardware instruction to interrupt at each instruction so that a trap routine could be called, but I don't know enough of the X86 hardware to be able to confirm that.

Perhaps you should step back and tell us what it is that you are trying to do, and why you think you need this trace file ... cheers, drl