- Save/restore only registers that are used.
This includes Callee saved registers and Caller saved registers
(arguments and temporaries) for integer and FP registers.
- If there is a call in the interrupt handler, save/restore all
Caller saved registers (arguments and temporaries) and all FP registers.
- Emit special return instructions depending on "interrupt"
attribute type.
Based on initial patch by Zhaoshi Zheng.
Reviewers: asb
Reviewed By: asb
Subscribers: rkruppe, the_o, MartinMosbeck, brucehoult, rbar, johnrusso, simoncook, sabuasal, niosHD, kito-cheng, shiva0217, zzheng, edward-jones, mgrang, rogfer01, llvm-commits
Differential Revision: https://reviews.llvm.org/D48411
llvm-svn: 338047
The TableGen-based calling convention definitions are inflexible, while
writing a function to implement the calling convention is very
straight-forward, and allows difficult cases to be handled more easily. With
this patch adds support for:
* Passing large scalars according to the RV32I calling convention
* Byval arguments
* Passing values on the stack when the argument registers are exhausted
The custom CC_RISCV calling convention is also used for returns.
This patch also documents the ABI lowering that a language frontend is
expected to perform. I would like to work to simplify these requirements over
time, but this will require further discussion within the LLVM community.
We add PendingArgFlags CCState, as a companion to PendingLocs.
The PendingLocs vector is used by a number of backends to handle arguments
that are split during legalisation. However CCValAssign doesn't keep track of
the original argument alignment. Therefore, add a PendingArgFlags vector which
can be used to keep track of the ISD::ArgFlagsTy for every value added to
PendingLocs.
Differential Revision: https://reviews.llvm.org/D39898
llvm-svn: 320359
A good portion of this patch is the extra functions that needed to be
implemented to support the test case. e.g. storeRegToStackSlot,
loadRegFromStackSlot, eliminateFrameIndex.
Setting ISD::BR_CC to Expand may appear non-obvious on an architecture with
branch+cmp instructions. However, I found it much easier to deal with matching
the expanded form.
I had to change simm13_lsb0 and simm21_lsb0 to inherit from the
Operand<OtherVT> class rather than Operand<i32> in order to keep tablegen
happy. This isn't a big deal, but it does seem a shame to lose the uniformity
across immediate types when there's not an obvious benefit (I'm hoping a
tablegen expert will educate me on what I'm missing here!).
Differential Revision: https://reviews.llvm.org/D29935
llvm-svn: 317690
This adds the minimum necessary to support codegen for simple ALU operations
on RV32. Prolog and epilog insertion, support for memory operations etc etc
follow in future patches.
Leave guessInstructionProperties=1 until https://reviews.llvm.org/D37065 is
reviewed and lands.
Differential Revision: https://reviews.llvm.org/D29933
llvm-svn: 316188
Ana Pazos