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Instruction

Synopsis

data RegUsage = RU [Reg] [Reg]
noUsage :: RegUsage
type NatCmm instr = GenCmm CmmStatic [CmmStatic] (ListGraph instr)
type NatCmmTop instr = GenCmmTop CmmStatic [CmmStatic] (ListGraph instr)
type NatBasicBlock instr = GenBasicBlock instr
class Instruction instr where

regUsageOfInstr :: instr -> RegUsage
patchRegsOfInstr :: instr -> (Reg -> Reg) -> instr
isJumpishInstr :: instr -> Bool
jumpDestsOfInstr :: instr -> [BlockId]
patchJumpInstr :: instr -> (BlockId -> BlockId) -> instr
mkSpillInstr :: Reg -> Int -> Int -> instr
mkLoadInstr :: Reg -> Int -> Int -> instr
takeDeltaInstr :: instr -> Maybe Int
isMetaInstr :: instr -> Bool
mkRegRegMoveInstr :: Reg -> Reg -> instr
takeRegRegMoveInstr :: instr -> Maybe (Reg, Reg)
mkJumpInstr :: BlockId -> [instr]

Documentation
data RegUsage

Holds a list of source and destination registers used by a particular instruction. Machine registers that are pre-allocated to stgRegs are filtered out, because they are uninteresting from a register allocation standpoint. (We wouldn't want them to end up on the free list!) As far as we are concerned, the fixed registers simply don't exist (for allocation purposes, anyway).
Constructors

RU [Reg] [Reg] |

noUsage :: RegUsage
No regs read or written to.
type NatCmm instr = GenCmm CmmStatic [CmmStatic] (ListGraph instr)
type NatCmmTop instr = GenCmmTop CmmStatic [CmmStatic] (ListGraph instr)
type NatBasicBlock instr = GenBasicBlock instr
class Instruction instr where

Common things that we can do with instructions, on all architectures. These are used by the shared parts of the native code generator, specifically the register allocators.
Methods

regUsageOfInstr :: instr -> RegUsage
Get the registers that are being used by this instruction. regUsage doesn't need to do any trickery for jumps and such. Just state precisely the regs read and written by that insn. The consequences of control flow transfers, as far as register allocation goes, are taken care of by the register allocator.
patchRegsOfInstr :: instr -> (Reg -> Reg) -> instr
Apply a given mapping to all the register references in this instruction.
isJumpishInstr :: instr -> Bool
Checks whether this instruction is a jump/branch instruction. One that can change the flow of control in a way that the register allocator needs to worry about.
jumpDestsOfInstr :: instr -> [BlockId]
Give the possible destinations of this jump instruction. Must be defined for all jumpish instructions.
patchJumpInstr :: instr -> (BlockId -> BlockId) -> instr
Change the destination of this jump instruction. Used in the linear allocator when adding fixup blocks for join points.
mkSpillInstr

:: Reg | the reg to spill
-> Int | the current stack delta
-> Int | spill slot to use
-> instr |
An instruction to spill a register into a spill slot.

mkLoadInstr

:: Reg | the reg to reload.
-> Int | the current stack delta
-> Int | the spill slot to use
-> instr |
An instruction to reload a register from a spill slot.

takeDeltaInstr :: instr -> Maybe Int
See if this instruction is telling us the current C stack delta
isMetaInstr :: instr -> Bool
Check whether this instruction is some meta thing inserted into the instruction stream for other purposes. Not something that has to be treated as a real machine instruction and have its registers allocated. eg, comments, delta, ldata, etc.
mkRegRegMoveInstr

:: Reg | source register
-> Reg | destination register
-> instr |
Copy the value in a register to another one. Must work for all register classes.

takeRegRegMoveInstr :: instr -> Maybe (Reg, Reg)
Take the source and destination from this reg -> reg move instruction or Nothing if it's not one
mkJumpInstr :: BlockId -> [instr]
Make an unconditional jump instruction. For architectures with branch delay slots, its ok to put a NOP after the jump. Don't fill the delay slot with an instruction that references regs or you'll confuse the linear allocator.

Instances

Instruction Instr
Instruction Instr
Instruction Instr

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