title: In CUDA's PTX file, what is the purpose of the ".file" directive?
body: <p>From what I understand, CUDA's PTX file is the virtual bytecode that is JIT compiled by the device runtime. This means that the file is cross platform, you can generate the PTX file and it will run on any CUDA compatible device. However, when I read the file in a text editor, I see these directives ".file" which have information about files on the original computer I compiled it for. So I am unsure what the purpose of these directives are. Also, given that my generated PTX files shouldn't be dependent on these files, can these safely be removed? (Like if I wanted to start writing my own PTX generator).</p>