ghc-7.0.1: The GHC API




data RegUsage Source

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).


RU [Reg] [Reg] 

noUsage :: RegUsageSource

No regs read or written to.

class Instruction instr whereSource

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.


regUsageOfInstr :: instr -> RegUsageSource

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) -> instrSource

Apply a given mapping to all the register references in this instruction.

isJumpishInstr :: instr -> BoolSource

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]Source

Give the possible destinations of this jump instruction. Must be defined for all jumpish instructions.

patchJumpInstr :: instr -> (BlockId -> BlockId) -> instrSource

Change the destination of this jump instruction. Used in the linear allocator when adding fixup blocks for join points.



:: 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.



:: 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 IntSource

See if this instruction is telling us the current C stack delta

isMetaInstr :: instr -> BoolSource

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.



:: 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)Source

Take the source and destination from this reg -> reg move instruction or Nothing if it's not one

mkJumpInstr :: BlockId -> [instr]Source

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.


Instruction Instr

Instruction instance for x86 instruction set.

Instruction Instr

Instruction instance for powerpc

Instruction Instr

instance for sparc instruction set

Instruction instr => Instruction (InstrSR instr)