Bump rocket, make possible to use published deps

[grebe]

• Overriding SBT to sbt -DROCKET_USE_MAVEN ++2.12.4 causes build to ignore testchipip and rocket-chip, instead using published dependencies. If you don't override SBT, it uses the submodules as before
• The build uses firrtl_black_box_resources.f to include blackboxes instead of hardcoded paths. This cleans up the build a bit, only including things you actually use
  • One caveat is that some blackboxes haven't been included correctly. This PR fixes the main one, and i want to clean up verisim/csrc a bit.
• bootrom is moved into project-template- maybe it shouldn't be in testchipip? I think it makes more sense here
• barstools is still a submodule. I would like to update it to use the new stages/phase stuff so it works nicely as a maven dep (also, we wouldn't need separate make targets to invoke barstools multiple times)
• Oh, and I also update the example a bit to work with current rocket

[jwright6323]

What's the motivation to move the verisim/csrc stuff out of testchipip? Or is it different somehow?

[grebe]

My latest commit removes verisim/vsrc and all but a couple headers in verisim/csrc.

I made a transform based on the blackboxresource transform to attach some resources to the TestHarness. This adds the csrc. Ideally, I would conditionally include emulator.cc only if I know I'm building with verilator.

Headers are tricky because they should be included with the -include flag, which the blackboxresource annotation doesn't have a way of doing. I think it will need to stay more hardcoded in the Makefile, unfortunately. Still, I should be able to have TestHarness pull the headers from resources instead of having them copied into the repo.

[jwright6323]

@grebe what about something like this: f99ac28

[grebe]

Yeah, that's sort of what I'm thinking

[zhemao]

We had bootrom in project-template initially, but eventually moved it to testchipip. I'd rather we keep it there.

[grebe]

@zhemao do you think it's OK to put bootrom in testchipip's src/main/resources? Symlinks could preserve the current layout for build scripts. If we're going to keep it in testchipip, it needs to end up in the jar somehow for use-cases that pull from maven.

[zhemao]

Yeah, we could put it in src/main/resources.

[grebe]

Now bootrom/ is generated (along with the other necessary c++/verilog files) as a build rule before running the rocket generator. Bootrom gets put in the top level directory, and everything else winds up in $(build_dir). Now, all you need to do is source two .f files, one of which contains black boxes and the other of which contains files (and command line flags) that verilator needs.

[jwright6323]

Approving per rebar feedback