| .. _porting: |
| |
| Porting GlobalISel to A New Target |
| ================================== |
| |
| There are four major classes to implement by the target: |
| |
| * :ref:`CallLowering <translator-call-lower>` --- lower calls, returns, and |
| arguments according to the ABI. |
| * :ref:`RegisterBankInfo <api-registerbankinfo>` --- describe |
| :ref:`gmir-regbank` coverage, cross-bank copy cost, and the mapping of |
| operands onto banks for each instruction. |
| * :ref:`LegalizerInfo <api-legalizerinfo>` --- describe what is legal, and how |
| to legalize what isn't. |
| * :ref:`InstructionSelector <api-instructionselector>` --- select generic MIR |
| to target-specific MIR. |
| |
| Additionally: |
| |
| * ``TargetPassConfig`` --- create the passes constituting the pipeline, |
| including additional passes not included in the :ref:`pipeline`. |
| |
| Tutorials |
| ========= |
| |
| We'd recommend watching `this tutorial |
| <https://www.llvm.org/devmtg/2017-10/#tutorial2>`_ from the 2017 LLVM DevMeeting |
| which gave an overview of how to bring up a new backend in GlobalISel. |
