Move VirtAddrMap out of ElfEdit.Dynamic

[langston-barrett]

This datatype isn't intrinsically related to dynamically-linked executables, so its placement in this module is a bit misleading.

[joehendrix]

I view that as a pretty simple data that is used to support the needs of parsing the dynamic section. It's it's useful for dynamic libraries and executables. I suppose it could be used for static executables as well, but not for object files.

I'm not opposed to having it in a separate module though if that would be useful, and you want to submit a PR.

[langston-barrett]

Ah, I didn't think of it as specific to the parsing of the dynamic section because it is exported. Perhaps we should just not export it instead? Which would be best?

[joehendrix]

I don't know what would be best. What's the goal of either change?

[joehendrix]

I took a brief look to repage things in and it looks like it's only used to support the Android relocation entries in Macaw. Maybe there's some other way to refactor that code so we don't need this type, but I don't understand the goal.

[langston-barrett]

Sorry if my comments were unclear, let me back up a bit. At the moment, VirtAddrMap and a handful of operations on it are exported out of ElfEdit.Dynamic, and then again out of ElfEdit. I think that every part of a library's API should:

1. be generally useful outside of that library's implementation, and
2. be organized logically into modules

among other things. Since VirtAddrMap is exported, I assumed that it was generally useful (1). Since it doesn't seem intrinsically tied to dynamically linked code (as you say, it could be used for static executables), I thought it should go in a module that's not specifically related to dynamically linked code (2).

Then you said:

I view that as a pretty simple data that is used to support the needs of parsing the dynamic section.

So I thought my assumption (1) was flawed, and so instead of making this type and its operations more suitable for exposing through the API, maybe we should just not export it and keep it internal to ElfEdit.Dynamic.