llvm-6502/lib/Target/MSP430
Dan Gohman 98ca4f2a32 Major calling convention code refactoring.
Instead of awkwardly encoding calling-convention information with ISD::CALL,
ISD::FORMAL_ARGUMENTS, ISD::RET, and ISD::ARG_FLAGS nodes, TargetLowering
provides three virtual functions for targets to override:
LowerFormalArguments, LowerCall, and LowerRet, which replace the custom
lowering done on the special nodes. They provide the same information, but
in a more immediately usable format.

This also reworks much of the target-independent tail call logic. The
decision of whether or not to perform a tail call is now cleanly split
between target-independent portions, and the target dependent portion
in IsEligibleForTailCallOptimization.

This also synchronizes all in-tree targets, to help enable future
refactoring and feature work.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@78142 91177308-0d34-0410-b5e6-96231b3b80d8
2009-08-05 01:29:28 +00:00
..
TargetInfo
CMakeLists.txt
Makefile
MSP430.h
MSP430.td
MSP430AsmPrinter.cpp Don't flush the raw_ostream between each MachineFunction. These flush 2009-08-05 00:49:25 +00:00
MSP430CallingConv.td
MSP430InstrFormats.td
MSP430InstrInfo.cpp
MSP430InstrInfo.h
MSP430InstrInfo.td
MSP430ISelDAGToDAG.cpp
MSP430ISelLowering.cpp Major calling convention code refactoring. 2009-08-05 01:29:28 +00:00
MSP430ISelLowering.h Major calling convention code refactoring. 2009-08-05 01:29:28 +00:00
MSP430MachineFunctionInfo.h
MSP430RegisterInfo.cpp
MSP430RegisterInfo.h
MSP430RegisterInfo.td
MSP430Subtarget.cpp Normalize Subtarget constructors to take a target triple string instead of 2009-08-02 22:11:08 +00:00
MSP430Subtarget.h Normalize Subtarget constructors to take a target triple string instead of 2009-08-02 22:11:08 +00:00
MSP430TargetAsmInfo.cpp
MSP430TargetAsmInfo.h
MSP430TargetMachine.cpp Move most targets TargetMachine constructor to only taking a target triple. 2009-08-02 23:37:13 +00:00
MSP430TargetMachine.h Move most targets TargetMachine constructor to only taking a target triple. 2009-08-02 23:37:13 +00:00
README.txt

//===---------------------------------------------------------------------===//
// MSP430 backend.
//===---------------------------------------------------------------------===//

DISCLAIMER: Thid backend should be considered as highly experimental. I never
seen nor worked with this MCU, all information was gathered from datasheet
only. The original intention of making this backend was to write documentation
of form "How to write backend for dummies" :) Thes notes hopefully will be
available pretty soon.

Some things are incomplete / not implemented yet (this list surely is not
complete as well):

0. Implement asmprinting for variables :)

1. Verify, how stuff is handling implicit zext with 8 bit operands (this might
be modelled currently in improper way - should we need to mark the superreg as
def for every 8 bit instruction?).

2. Libcalls: multiplication, division, remainder. Note, that calling convention
for libcalls is incomptible with calling convention of libcalls of msp430-gcc
(these cannot be used though due to license restriction).

3. Implement multiplication / division by constant (dag combiner hook?).

4. Implement non-constant shifts.

5. Implement varargs stuff.

6. Verify and fix (if needed) how's stuff playing with i32 / i64.

7. Implement floating point stuff (softfp?)

8. Implement instruction encoding for (possible) direct code emission in the
future.

9. Since almost all instructions set flags - implement brcond / select in better
way (currently they emit explicit comparison).

10. Handle imm in comparisons in better way (see comment in MSP430InstrInfo.td)

11. Implement hooks for better memory op folding, etc.