1.. _porting:
2
3Porting GlobalISel to A New Target
4==================================
5
6There are four major classes to implement by the target:
7
8* :ref:`CallLowering <translator-call-lower>` --- lower calls, returns, and
9  arguments according to the ABI.
10* :ref:`RegisterBankInfo <api-registerbankinfo>` --- describe
11  :ref:`gmir-regbank` coverage, cross-bank copy cost, and the mapping of
12  operands onto banks for each instruction.
13* :ref:`LegalizerInfo <api-legalizerinfo>` --- describe what is legal, and how
14  to legalize what isn't.
15* :ref:`InstructionSelector <api-instructionselector>` --- select generic MIR
16  to target-specific MIR.
17
18Additionally:
19
20* ``TargetPassConfig`` --- create the passes constituting the pipeline,
21  including additional passes not included in the :ref:`pipeline`.
22
23Tutorials
24=========
25
26We'd recommend watching `this tutorial
27<https://www.llvm.org/devmtg/2017-10/#tutorial2>`_ from the 2017 LLVM DevMeeting
28which gave an overview of how to bring up a new backend in GlobalISel.
29