absolute locations of functions?

Is there anyway to write a pass/plugin so I can print the locations of all functions? Can anything run after the linker? I’m not sure what I should be reading up on to tackle this.

Thanks

If you mean their location in the resulting binary, then you don't need a plugin to do this: the nm utility will do it for you. It will print the location of all symbols, but you can use the example clang plugin to print the names of all functions and then use this to filter the output of nm.

If you mean that location in the address space of a running program, then this is not possible with a clang plugin, because this location is not defined until after the program / library has been loaded, and on modern systems will be randomised on each program run as a security precaution.

David

Is there a separate flag to use so locations are printed in nm? The only relevant flag I have seen in the man page is -cppgen=functions and that does not show addresses.

Thanks again

No, the default output from nm shows the location, type, and name of every symbol in a binary. No additional flags are required.

David

No, the default output from nm shows the location, type, and name of every symbol in a binary. No additional flags are required.

If working with a dynamic library, I believe you will also need the
dynamic switch (-D or --dynamic). Otherwise, some symbols are reported
as undefined.

Jeff

Is there a direct way to get the location in the binary, as a plugin? I think that would be a nicer form for me, if possible.

Thanks

Clang doesn't have this information. I think you can use the Object stuff in LLVM to get it after the binary has been generated, but it's not trivial, because this doesn't happen until after the linker has run, and in nontrivial cases the linker is not run by the same program invocation as the compiler.

What problem are you actually trying to solve?

David

The end goal for this(and another post to this list) is to general a file that contains all functions and the function calls they make, along with the addresses(of each) in the binary. Having names would be great for debugging. I figured at the very least I can get the function calls as a plugin.

Originally I was trying to modify the dot-callgraph pass, but modying the GraphWriter to be more generic than a dot file was a bit tricky. As a plugin seems more convent also.