[LLVMdev] Extracting libmachine from libcodegen (bug 1121)

[Ken Dyck]

Hi,

One of the long-standing code clean-up bugs in Bugzilla is to extract
the Machine* code from the CodeGen library into a separate one, on
which CodeGen depends (
http://llvm.org/bugs/show_bug.cgi?id=1121).

I'd like to start working on this. The general approach I'm planning to take is:

1. Identify which code to move.
2. Eliminate all dependencies that the Machine code has on the CodeGen
code (details to be fleshed out on llvmdev as they are encountered).
3. Create a library project for the Machine code
4. Move the code to the new library.

Do you have any concerns about the feasibility this approach?

As to step 1, I haven't dug too deeply into the problem yet, but I'm
starting from the assumption that we'll be moving only the modules
that start with 'Machine' into the new library. These are:

- MachineBasicBlock
- MachineBlockFrequencyInfo
- MachineBlockPlacement
- MachineBranchProbabilityInfo
- MachineCodeEmitter
- MachineCopyPropagation
- MachineCSE
- MachineDominators
- MachineFunctionAnalysis
- MachineFunction
- MachineFunctionPass
- MachineFunctionPrinterPass
- MachineInstrBundle
- MachineInstr
- MachineLICM
- MachineLoopInfo
- MachineModuleInfo
- MachineModuleInfoImpls
- MachinePassRegistry
- MachinePostDominators
- MachineRegisterInfo
- MachineScheduler
- MachineSink
- MachineSSAUpdater
- MachineTraceMetrics
- MachineVerifier

Are there any files in this list that should not be moved? Any others
that should be added? Any suggestions on which of these modules would
be a good place to start?

One question of procedure... Back in 2010 and 2011, I had commit
rights on the LLVM svn repository because of work I was doing on
Clang. I'm not sure whether my account is still active, but if you'd
like I re-qualify myself as a contributor by submitting patches to
llvm-commits instead of making changes directly to the repository,
just let me know.

-Ken