Up until now, if one wanted to specify an explicit stack location or register as an operand for an instruction, it had to also be
explicitly associated with a virtual register as a so-called
FixedRegister or FixedStackSlot.
For the implementation of tail calls, the plan is to use the gap
resolver needs to shuffle stack locations from the caller to the
tail-called callee. In order to do this, it must be possible to
explicitly address operand locations on the stack that are not
associated with virtual registers.
This CL introduces ExplictOperands, which can specify a specific
register or stack location that is not associated with virtual
register. This will allow tail calls to specify the target
locations for the necessary stack moves in the gap for the tail
call without the core register allocation having to know about
the target of the stack moves at all.
In the process this CL:
* creates a new Operand kind, ExplicitOperand, with which
instructions can specify register and stack slots without an
associated virtual register.
* creates a LocationOperand class from which AllocatedOperand and
ExplicitOperand are derived and provides a common interface to
get Register, DoubleRegister and spill slot information.
* removes RegisterOperand, DoubleRegisterOperand,
StackSlotOperand and DoubleStackSlotOperand, they are subsumed
by LocationOperand.
* addresses a cleanup TODO in AllocatedOperand to reduce the
redundancy of AllocatedOperand::Kind by using machine_type() to
determine if an operand corresponds to a general purpose or
double register.
BUG=v8:4076
LOG=n
Review URL: https://codereview.chromium.org/1389373002
Cr-Commit-Position: refs/heads/master@{#31603}
- allows the optimization of emitted gap move code since the representation of the value in the register is known
- necessary preparation for vector register allocation
- prepare for slot sharing for any value of the same byte width
TBR=jarin@chromium.org
BUG=
Review URL: https://codereview.chromium.org/1111323003
Cr-Commit-Position: refs/heads/master@{#28140}
- allows the optimization of emitted gap move code since the representation of the value in the register is known
- necessary preparation for vector register allocation
- prepare for slot sharing for any value of the same byte width
BUG=
Review URL: https://codereview.chromium.org/1087793002
Cr-Commit-Position: refs/heads/master@{#28137}
- make ParallelMove into a ZoneVector, removing an annoying level of indirection
- make MoveOperands hold InstructionOperands instead of pointers, so there's no more operand aliasing for moves
- opens up possibility of storing MachineType in allocated operands
R=bmeurer@chromium.org
BUG=
Review URL: https://codereview.chromium.org/1081373002
Cr-Commit-Position: refs/heads/master@{#27842}
- ConstantOperand was using a too-small field too store its virtual register
- drop ConvertTo, replace it with simple copy
- split AllocatedOperand off from Immediate and Constant to make assignment clearer, also paving the way for small Immediates
- put zone first in *Operand::New
- driveby: drop delayed ssa deconstruction experiment
R=titzer@chromium.org
BUG=
Review URL: https://codereview.chromium.org/1050803002
Cr-Commit-Position: refs/heads/master@{#27692}
