ghc-7.4.2: The GHC API

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Instruction

Synopsis

- data RegUsage = RU [Reg] [Reg]
- noUsage :: RegUsage
- type NatCmm instr = GenCmmGroup CmmStatics (Maybe CmmStatics) (ListGraph instr)
- type NatCmmDecl statics instr = GenCmmDecl statics (Maybe CmmStatics) (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 :: Platform -> Reg -> Int -> Int -> instr
  - mkLoadInstr :: Platform -> Reg -> Int -> Int -> instr
  - takeDeltaInstr :: instr -> Maybe Int
  - isMetaInstr :: instr -> Bool
  - mkRegRegMoveInstr :: Platform -> 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 = GenCmmGroup CmmStatics (Maybe CmmStatics) (ListGraph instr)

type NatCmmDecl statics instr = GenCmmDecl statics (Maybe CmmStatics) (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

Arguments

:: Platform |
-> 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

Arguments

:: Platform |
-> 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

Arguments

:: Platform |
-> 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 instance for x86 instruction set.
Instruction Instr | instance for sparc instruction set
Instruction Instr | Instruction instance for powerpc
Instruction instr => Instruction (InstrSR instr) |