Fixes#175.
The Intel division instructions have fixed input operands that are
clobbered by fixed output operands, so the value passed as an input will
be clobbered just like a tied operand.
The FixedTied operand constraint is used to indicate a fixed input
operand that has a corresponding output operand with the same fixed
register.
Teach the spiller to teach a FixedTied operand the same as a Tied
operand constraint and make sure that the input value is killed by the
instruction.
This makes it possible to define register banks that opt out of register
pressure tracking. This will be used to define banks for special-purpose
registers like the CPU flags.
The pressure tracker does not need to use resources for a top-level
register class in a non-tracked bank. The constant MAX_TOPRCS is renamed
to MAX_TRACKED_TOPRCS to indicate that there may be top-level register
classes with higher numbers, but they won't require pressure tracking.
We won't be tracking register pressure for CPU flags since only one
value is allowed to be live at a time.
This contains encoding details for a stack reference: The base register
and offset to use in the specific instruction encoding.
Generate StackRef objects called in_stk0 etc for the binemit recipe
code. All binemit recipes need to compute base pointer offsets for stack
references, so have the automatically generated code do it.
Add a Stack() class for specifying operand constraints for values on the
stack.
Add encoding recipes for RISC-V spill and fill instructions. Don't
implement the encoding recipe functions yet since we don't have the
stack slot layout yet.
A top-level register class is one that has no sub-classes. It is
possible to have multiple top-level register classes in the same
register bank. For example, ARM's FPR bank has both D and Q top-level
register classes.
Number register classes such that all top-level register classes appear
as a contiguous sequence starting from 0. This will be used by the
register allocator when counting used registers per top-level register
class.
These instructions have a fixed register constraint; the shift amount is
passed in CL.
Add meta language syntax so a fixed register can be specified as
"GPR.rcx".
The List and Dict types are no longer implicitly available. They must be
imported from typing.
Type annotations must appear before the doc comment in a function. Also
fix type errors in these functions that weren't detected before.
Ensure that the set of register classes is closed under intersection.
Provide a RegClass::intersect() method which finds the register class
representing the intersection of two classes.
Generate a bit-mask of subclasses for each register class to be used by
the intersect() method.
Ensure that register classes are sorted topologically. This is also used
by the intersect() method.
Every encoding recipe must specify register constraints on input and
output values.
Generate recipe constraint tables along with the other encoding tables.
This set of available register units also manages register aliasing in
an efficient way.
Detect if the units in a register straddles mask words. The algorithm
for allocating multi-unit registers expect the whole register to be
inside a single mask word. We could handle this if necessary, but so far
no ISAs need it.
Add a RegBank class for describing CPU register banks.
Define register banks for all the ISA stubs. The ARM32 floating point
bank in particular requires attention.
