- unknown_block = panic "unknown BlockId in applyStackFormat"
-
------------------------------------------------------------------------------
-continuationToProc :: (WordOff, [(CLabel, StackFormat)])
- -> Continuation CmmInfo
- -> CmmTop
-continuationToProc (max_stack, formats)
- (Continuation info label formals blocks) =
- CmmProc info label formals (map continuationToProc' blocks)
- where
- curr_format = maybe unknown_block id $ lookup label formats
- unknown_block = panic "unknown BlockId in continuationToProc"
-
- continuationToProc' :: BrokenBlock -> CmmBasicBlock
- continuationToProc' (BrokenBlock ident entry stmts _ exit) =
- BasicBlock ident (prefix++stmts++postfix)
- where
- prefix = case entry of
- ControlEntry -> []
- FunctionEntry (CmmInfo _ (Just gc_block) _ _) _ formals ->
- gc_stack_check gc_block max_stack ++
- function_entry formals curr_format
- FunctionEntry (CmmInfo _ Nothing _ _) _ formals ->
- panic "continuationToProc: TODO generate GC block" ++
- function_entry formals curr_format
- FunctionEntry CmmNonInfo _ formals ->
- panic "TODO: gc_stack_check gc_block max_stack" ++
- function_entry formals curr_format
- ContinuationEntry formals _ ->
- function_entry formals curr_format
- postfix = case exit of
- FinalBranch next -> [CmmBranch next]
- FinalSwitch expr targets -> [CmmSwitch expr targets]
- FinalReturn arguments ->
- tail_call (stack_frame_size curr_format)
- (CmmLoad (CmmReg spReg) wordRep)
- arguments
- FinalJump target arguments ->
- tail_call (stack_frame_size curr_format) target arguments
- FinalCall next (CmmForeignCall target CmmCallConv)
- results arguments ->
- pack_continuation curr_format cont_format ++
- tail_call (stack_frame_size curr_format - stack_frame_size cont_format)
- target arguments
- where
- cont_format = maybe unknown_block id $
- lookup (mkReturnPtLabel $ getUnique next) formats
- FinalCall next _ results arguments -> panic "unimplemented CmmCall"
-
------------------------------------------------------------------------------
--- Functions that generate CmmStmt sequences
--- for packing/unpacking continuations
--- and entering/exiting functions
-
-tail_call :: WordOff -> CmmExpr -> CmmActuals -> [CmmStmt]
-tail_call spRel target arguments
- = store_arguments ++ adjust_spReg ++ jump where
- store_arguments =
- [stack_put spRel expr offset
- | ((expr, _), StackParam offset) <- argument_formats] ++
- [global_put expr global
- | ((expr, _), RegisterParam global) <- argument_formats]
- adjust_spReg =
- if spRel == 0
- then []
- else [CmmAssign spReg (CmmRegOff spReg (spRel*wORD_SIZE))]
- jump = [CmmJump target arguments]
-
- argument_formats = assignArguments (cmmExprRep . fst) arguments
-
-gc_stack_check :: BlockId -> WordOff -> [CmmStmt]
-gc_stack_check gc_block max_frame_size
- = check_stack_limit where
- check_stack_limit = [
- CmmCondBranch
- (CmmMachOp (MO_U_Lt $ cmmRegRep spReg)
- [CmmRegOff spReg max_frame_size, CmmReg spLimReg])
- gc_block]
-
--- TODO: fix branches to proc point (we have to insert a new block to marshel the continuation)
-pack_continuation :: StackFormat -> StackFormat -> [CmmStmt]
-pack_continuation (StackFormat curr_id curr_frame_size _)
- (StackFormat cont_id cont_frame_size live_regs)
- = store_live_values ++ set_stack_header where
- -- TODO: only save variables when actually needed
- -- (may be handled by latter pass)
- store_live_values =
- [stack_put spRel (CmmReg (CmmLocal reg)) offset
- | (reg, offset) <- cont_offsets]
- set_stack_header =
- if needs_header_set
- then [stack_put spRel continuation_function 0]
- else []
-
- -- TODO: factor with function_entry and CmmInfo.hs(?)
- cont_offsets = mkOffsets label_size live_regs
-
- label_size = 1 :: WordOff
-
- mkOffsets size [] = []
- mkOffsets size (Nothing:regs) = mkOffsets (size+1) regs
- mkOffsets size (Just reg:regs) = (reg, size):mkOffsets (size + width) regs
- where
- width = machRepByteWidth (localRegRep reg) `quot` wORD_SIZE
- -- TODO: it would be better if we had a machRepWordWidth
-
- spRel = curr_frame_size - cont_frame_size
- continuation_function = CmmLit $ CmmLabel $ fromJust cont_id
- needs_header_set =
- case (curr_id, cont_id) of
- (Just x, Just y) -> x /= y
- _ -> isJust cont_id
-
--- Lazy adjustment of stack headers assumes all blocks
--- that could branch to eachother (i.e. control blocks)
--- have the same stack format (this causes a problem
--- only for proc-point).
-function_entry :: CmmFormals -> StackFormat -> [CmmStmt]
-function_entry formals (StackFormat _ _ live_regs)
- = load_live_values ++ load_args where
- -- TODO: only save variables when actually needed
- -- (may be handled by latter pass)
- load_live_values =
- [stack_get 0 reg offset
- | (reg, offset) <- curr_offsets]
- load_args =
- [stack_get 0 reg offset
- | (reg, StackParam offset) <- argument_formats] ++
- [global_get reg global
- | (reg, RegisterParam global) <- argument_formats]
-
- argument_formats = assignArguments (localRegRep) formals
-
- -- TODO: eliminate copy/paste with pack_continuation
- curr_offsets = mkOffsets label_size live_regs
-
- label_size = 1 :: WordOff
-
- mkOffsets size [] = []
- mkOffsets size (Nothing:regs) = mkOffsets (size+1) regs
- mkOffsets size (Just reg:regs) = (reg, size):mkOffsets (size + width) regs
- where
- width = machRepByteWidth (localRegRep reg) `quot` wORD_SIZE
- -- TODO: it would be better if we had a machRepWordWidth
-
------------------------------------------------------------------------------
--- Section: Stack and argument register puts and gets
------------------------------------------------------------------------------
--- TODO: document
-
--- |Construct a 'CmmStmt' that will save a value on the stack
-stack_put :: WordOff -- ^ Offset from the real 'Sp' that 'offset'
- -- is relative to (added to offset)
- -> CmmExpr -- ^ What to store onto the stack
- -> WordOff -- ^ Where on the stack to store it
- -- (positive <=> higher addresses)
- -> CmmStmt
-stack_put spRel expr offset =
- CmmStore (CmmRegOff spReg (wORD_SIZE*(spRel + offset))) expr
-
---------------------------------
--- |Construct a
-stack_get :: WordOff
- -> LocalReg
- -> WordOff
- -> CmmStmt
-stack_get spRel reg offset =
- CmmAssign (CmmLocal reg)
- (CmmLoad (CmmRegOff spReg (wORD_SIZE*(spRel + offset)))
- (localRegRep reg))
-global_put :: CmmExpr -> GlobalReg -> CmmStmt
-global_put expr global = CmmAssign (CmmGlobal global) expr
-global_get :: LocalReg -> GlobalReg -> CmmStmt
-global_get reg global = CmmAssign (CmmLocal reg) (CmmReg (CmmGlobal global))