%
% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
-% $Id: CgStackery.lhs,v 1.9 1998/12/02 13:17:51 simonm Exp $
+% $Id: CgStackery.lhs,v 1.24 2003/11/17 14:42:47 simonmar Exp $
%
\section[CgStackery]{Stack management functions}
\begin{code}
module CgStackery (
- allocStack, allocPrimStack, allocStackTop, deAllocStackTop,
- allocUpdateFrame,
- adjustRealSp, adjustStackHW, getFinalStackHW,
- mkTaggedVirtStkOffsets, mkTaggedStkAmodes, mkTagAssts,
- freeStackSlots, addFreeSlots
+ allocPrimStack, allocStackTop, deAllocStackTop,
+ adjustStackHW, getFinalStackHW,
+ setStackFrame, getStackFrame,
+ mkVirtStkOffsets, mkStkAmodes,
+ freeStackSlots, dataStackSlots,
+ updateFrameSize,
+ constructSlowCall, slowArgs,
) where
#include "HsVersions.h"
import CgMonad
import AbsCSyn
+import CLabel ( mkRtsApplyInfoLabel, mkRtsApplyEntryLabel )
import CgUsages ( getRealSp )
-import AbsCUtils ( mkAbstractCs, mkAbsCStmts, getAmodeRep )
-import PrimRep ( getPrimRepSize, PrimRep(..), isFollowableRep )
-import Util ( panic )
+import AbsCUtils ( mkAbstractCs, getAmodeRep )
+import PrimRep
+import CmdLineOpts ( opt_SccProfilingOn, opt_GranMacros )
+import Constants
+import Util ( sortLt )
+import FastString ( LitString )
+import Panic
+
+import TRACE ( trace )
\end{code}
%************************************************************************
%* *
%************************************************************************
-@mkTaggedVirtStkOffsets@ is given a list of arguments. The first
-argument gets the {\em largest} virtual stack offset (remember,
-virtual offsets increase towards the top of stack). This function
-also computes the correct tagging arrangement for standard function
-entry points. Each non-pointer on the stack is preceded by a tag word
-indicating the number of non-pointer words above it on the stack.
-
- offset --> | | <---- last allocated stack word
- --------- <
- | | .
- --------- .
- | | total_nptrs (words)
- --------- .
- | | .
- --------- <
-offset + tot_nptrs + 1 --> | tag |
- ---------
+'mkVirtStkOffsets' is given a list of arguments. The first argument
+gets the /largest/ virtual stack offset (remember, virtual offsets
+increase towards the top of stack).
\begin{code}
-mkTaggedVirtStkOffsets
+mkVirtStkOffsets
:: VirtualSpOffset -- Offset of the last allocated thing
-> (a -> PrimRep) -- to be able to grab kinds
-> [a] -- things to make offsets for
-> (VirtualSpOffset, -- OUTPUTS: Topmost allocated word
- [(a, VirtualSpOffset)], -- things with offsets
- [(VirtualSpOffset,Int)]) -- offsets for tags
+ [(a, VirtualSpOffset)]) -- things with offsets
-mkTaggedVirtStkOffsets init_Sp_offset kind_fun things
- = loop init_Sp_offset [] [] (reverse things)
+mkVirtStkOffsets init_Sp_offset kind_fun things
+ = loop init_Sp_offset [] (reverse things)
where
- loop offset tags offs [] = (offset,offs,tags)
- loop offset tags offs (t:things)
- | isFollowableRep (kind_fun t) =
- loop (offset+1) tags ((t,offset+1):offs) things
- | otherwise =
+ loop offset offs [] = (offset,offs)
+ loop offset offs (t:things) =
let
size = getPrimRepSize (kind_fun t)
- tag_slot = offset+size+1
+ thing_slot = offset + size
in
- loop tag_slot ((tag_slot,size):tags) ((t,offset+size):offs) things
+ loop thing_slot ((t,thing_slot):offs) things
-- offset of thing is offset+size, because we're growing the stack
-- *downwards* as the offsets increase.
-\end{code}
-@mkTaggedStkAmodes@ is a higher-level version of
-@mkTaggedVirtStkOffsets@. It starts from the tail-call locations. It
-returns a single list of addressing modes for the stack locations, and
-therefore is in the monad.
-It *doesn't* adjust the high water mark.
+-- | 'mkStkAmodes' is a higher-level version of
+-- 'mkVirtStkOffsets'. It starts from the tail-call locations.
+-- It returns a single list of addressing modes for the stack
+-- locations, and therefore is in the monad. It /doesn't/ adjust the
+-- high water mark.
-\begin{code}
-mkTaggedStkAmodes
+mkStkAmodes
:: VirtualSpOffset -- Tail call positions
-> [CAddrMode] -- things to make offsets for
-> FCode (VirtualSpOffset, -- OUTPUTS: Topmost allocated word
- AbstractC, -- Assignments to appropriate stk slots
- AbstractC) -- Assignments for tagging
+ AbstractC) -- Assignments to appropriate stk slots
-mkTaggedStkAmodes tail_Sp things
+mkStkAmodes tail_Sp things
= getRealSp `thenFC` \ realSp ->
let
- (last_Sp_offset, offsets, tags)
- = mkTaggedVirtStkOffsets tail_Sp getAmodeRep things
+ (last_Sp_offset, offsets) = mkVirtStkOffsets tail_Sp getAmodeRep things
abs_cs =
[ CAssign (CVal (spRel realSp offset) (getAmodeRep thing)) thing
| (thing, offset) <- offsets
]
-
- tag_cs =
- [ CAssign (CVal (spRel realSp offset) WordRep)
- (CMacroExpr WordRep ARG_TAG [mkIntCLit size])
- | (offset,size) <- tags
- ]
in
- returnFC (last_Sp_offset, mkAbstractCs abs_cs, mkAbstractCs tag_cs)
+ returnFC (last_Sp_offset, mkAbstractCs abs_cs)
+\end{code}
+
+%************************************************************************
+%* *
+\subsection{Pushing the arguments for a slow call}
+%* *
+%************************************************************************
-mkTagAssts :: [(VirtualSpOffset,Int)] -> FCode AbstractC
-mkTagAssts tags =
- getRealSp `thenFC` \realSp ->
- returnFC (mkAbstractCs
- [ CAssign (CVal (spRel realSp offset) WordRep)
- (CMacroExpr WordRep ARG_TAG [mkIntCLit size])
- | (offset,size) <- tags
- ])
+For a slow call, we must take a bunch of arguments and intersperse
+some stg_ap_<pattern>_ret_info return addresses.
+\begin{code}
+constructSlowCall :: [CAddrMode] -> (CAddrMode, [CAddrMode])
+ -- don't forget the zero case
+constructSlowCall [] = (CLbl stg_ap_0 CodePtrRep , [])
+constructSlowCall amodes =
+ -- traceSlowCall amodes $
+ (CLbl lbl CodePtrRep, these ++ slowArgs rest)
+ where (tag, these, rest) = matchSlowPattern amodes
+ lbl = mkRtsApplyEntryLabel tag
+
+stg_ap_0 = mkRtsApplyEntryLabel SLIT("0")
+
+-- | 'slowArgs' takes a list of function arguments and prepares them for
+-- pushing on the stack for "extra" arguments to a function which requires
+-- fewer arguments than we currently have.
+slowArgs :: [CAddrMode] -> [CAddrMode]
+slowArgs [] = []
+slowArgs amodes = CLbl lbl RetRep : args ++ slowArgs rest
+ where (tag, args, rest) = matchSlowPattern amodes
+ lbl = mkRtsApplyInfoLabel tag
+
+matchSlowPattern :: [CAddrMode] -> (LitString, [CAddrMode], [CAddrMode])
+matchSlowPattern amodes = (tag, these, rest)
+ where reps = map getAmodeRep amodes
+ (tag, n) = findMatch (map primRepToArgRep reps)
+ (these, rest) = splitAt n amodes
+
+-- These cases were found to cover about 99% of all slow calls:
+findMatch (RepP: RepP: RepP: RepP: RepP: RepP: RepP: _) = (SLIT("ppppppp"), 7)
+findMatch (RepP: RepP: RepP: RepP: RepP: RepP: _) = (SLIT("pppppp"), 6)
+findMatch (RepP: RepP: RepP: RepP: RepP: _) = (SLIT("ppppp"), 5)
+findMatch (RepP: RepP: RepP: RepP: _) = (SLIT("pppp"), 4)
+findMatch (RepP: RepP: RepP: _) = (SLIT("ppp"), 3)
+findMatch (RepP: RepP: RepV: _) = (SLIT("ppv"), 3)
+findMatch (RepP: RepP: _) = (SLIT("pp"), 2)
+findMatch (RepP: RepV: _) = (SLIT("pv"), 2)
+findMatch (RepP: _) = (SLIT("p"), 1)
+findMatch (RepV: _) = (SLIT("v"), 1)
+findMatch (RepN: _) = (SLIT("n"), 1)
+findMatch (RepF: _) = (SLIT("f"), 1)
+findMatch (RepD: _) = (SLIT("d"), 1)
+findMatch (RepL: _) = (SLIT("l"), 1)
+findMatch _ = panic "CgStackery.findMatch"
+
+#ifdef DEBUG
+primRepChar p | isFollowableRep p = 'p'
+primRepChar VoidRep = 'v'
+primRepChar FloatRep = 'f'
+primRepChar DoubleRep = 'd'
+primRepChar p | getPrimRepSize p == 1 = 'n'
+primRepChar p | is64BitRep p = 'l'
+
+traceSlowCall amodes and_then
+ = trace ("call: " ++ map primRepChar (map getAmodeRep amodes)) and_then
+#endif
\end{code}
%************************************************************************
Allocate a virtual offset for something.
\begin{code}
-allocStack :: FCode VirtualSpOffset
-allocStack = allocPrimStack 1
-
allocPrimStack :: Int -> FCode VirtualSpOffset
-allocPrimStack size info_down (MkCgState absC binds
- ((virt_sp, free_stk, real_sp, hw_sp), h_usage))
- = (chosen_slot, MkCgState absC binds (new_stk_usage, h_usage))
- where
- push_virt_sp = virt_sp + size
-
- (chosen_slot, new_stk_usage)
- = case find_block free_stk of
- Nothing -> (push_virt_sp, (push_virt_sp, free_stk, real_sp,
- hw_sp `max` push_virt_sp))
- -- Adjust high water mark
-
- Just slot -> (slot, (virt_sp,
- delete_block free_stk slot, real_sp, hw_sp))
-
- -- find_block looks for a contiguous chunk of free slots
- find_block :: [VirtualSpOffset] -> Maybe VirtualSpOffset
- find_block [] = Nothing
- find_block (slot:slots)
- | take size (slot:slots) == [slot..top_slot] = Just top_slot
- | otherwise = find_block slots
- -- The stack grows downwards, with increasing virtual offsets.
- -- Therefore, the address of a multi-word object is the *highest*
- -- virtual offset it occupies (top_slot below).
- where top_slot = slot+size-1
-
- delete_block free_stk slot = [s | s <- free_stk, (s<=slot-size) || (s>slot)]
+allocPrimStack size = do
+ ((virt_sp, frame, free_stk, real_sp, hw_sp),h_usage) <- getUsage
+ let push_virt_sp = virt_sp + size
+ let (chosen_slot, new_stk_usage) =
+ case find_block free_stk of
+ Nothing -> (push_virt_sp,
+ (push_virt_sp, frame, free_stk, real_sp,
+ hw_sp `max` push_virt_sp))
+ -- Adjust high water mark
+ Just slot -> (slot,
+ (virt_sp, frame,
+ delete_block free_stk slot,
+ real_sp, hw_sp))
+ setUsage (new_stk_usage, h_usage)
+ return chosen_slot
+
+ where
+ -- find_block looks for a contiguous chunk of free slots
+ find_block :: [(VirtualSpOffset,Slot)] -> Maybe VirtualSpOffset
+ find_block [] = Nothing
+ find_block ((off,free):slots)
+ | take size ((off,free):slots) ==
+ zip [off..top_slot] (repeat Free) = Just top_slot
+ | otherwise = find_block slots
+ -- The stack grows downwards, with increasing virtual offsets.
+ -- Therefore, the address of a multi-word object is the *highest*
+ -- virtual offset it occupies (top_slot below).
+ where top_slot = off+size-1
+
+ delete_block free_stk slot = [ (s,f) | (s,f) <- free_stk,
+ (s<=slot-size) || (s>slot) ]
-- Retain slots which are not in the range
-- slot-size+1..slot
+\end{code}
+
+Allocate a chunk ON TOP OF the stack.
+
+ToDo: should really register this memory as NonPointer stuff in the
+free list.
--- Allocate a chunk ON TOP OF the stack
+\begin{code}
allocStackTop :: Int -> FCode VirtualSpOffset
-allocStackTop size info_down (MkCgState absC binds
- ((virt_sp, free_stk, real_sp, hw_sp), h_usage))
- = (push_virt_sp, MkCgState absC binds (new_stk_usage, h_usage))
- where
- push_virt_sp = virt_sp + size
- new_stk_usage = (push_virt_sp, free_stk, real_sp, hw_sp `max` push_virt_sp)
- -- Adjust high water mark
+allocStackTop size = do
+ ((virt_sp, frame, free_stk, real_sp, hw_sp), h_usage) <- getUsage
+ let push_virt_sp = virt_sp + size
+ let new_stk_usage = (push_virt_sp, frame, free_stk, real_sp,
+ hw_sp `max` push_virt_sp)
+ setUsage (new_stk_usage, h_usage)
+ return push_virt_sp
\end{code}
Pop some words from the current top of stack. This is used for
\begin{code}
deAllocStackTop :: Int -> FCode VirtualSpOffset
-deAllocStackTop size info_down (MkCgState absC binds
- ((virt_sp, free_stk, real_sp, hw_sp), h_usage))
- = (pop_virt_sp, MkCgState absC binds (new_stk_usage, h_usage))
- where
- pop_virt_sp = virt_sp - size
- new_stk_usage = (pop_virt_sp, free_stk, real_sp, hw_sp)
-\end{code}
-
-@allocUpdateFrame@ allocates enough space for an update frame on the
-stack, records the fact in the end-of-block info (in the ``args''
-fields), and passes on the old ``args'' fields to the enclosed code.
-
-This is all a bit disgusting.
-
-\begin{code}
-allocUpdateFrame :: Int -- Size of frame
- -> Code -- Scope of update
- -> Code
-
-allocUpdateFrame size code
- (MkCgInfoDown c_info statics srt (EndOfBlockInfo args_Sp sequel))
- (MkCgState absc binds ((vSp,rr,qq,hwSp),h_usage))
- = case sequel of
-
- OnStack _ -> code (MkCgInfoDown c_info statics srt new_eob_info)
- (MkCgState absc binds new_usage)
-
- other -> panic "allocUpdateFrame"
-
- where
- new_vSp = vSp + size
- new_eob_info = EndOfBlockInfo new_vSp UpdateCode
- new_usage = ((new_vSp,rr,qq,hwSp `max` new_vSp), h_usage)
+deAllocStackTop size = do
+ ((virt_sp, frame, free_stk, real_sp, hw_sp), h_usage) <- getUsage
+ let pop_virt_sp = virt_sp - size
+ let new_stk_usage = (pop_virt_sp, frame, free_stk, real_sp, hw_sp)
+ setUsage (new_stk_usage, h_usage)
+ return pop_virt_sp
\end{code}
\begin{code}
adjustStackHW :: VirtualSpOffset -> Code
-adjustStackHW offset info_down (MkCgState absC binds usage)
- = MkCgState absC binds new_usage
- where
- ((vSp,fSp,realSp,hwSp), h_usage) = usage
- new_usage = ((vSp, fSp, realSp, max offset hwSp), h_usage)
- -- No need to fiddle with virtual Sp etc because this call is
- -- only done just before the end of a block
+adjustStackHW offset = do
+ ((vSp,fTop,fSp,realSp,hwSp), h_usage) <- getUsage
+ setUsage ((vSp, fTop, fSp, realSp, max offset hwSp), h_usage)
\end{code}
A knot-tying beast.
\begin{code}
getFinalStackHW :: (VirtualSpOffset -> Code) -> Code
-getFinalStackHW fcode info_down (MkCgState absC binds usages) = state1
- where
- state1 = fcode hwSp info_down (MkCgState absC binds usages)
- (MkCgState _ _ ((_,_,_, hwSp), _)) = state1
+getFinalStackHW fcode = do
+ fixC (\hwSp -> do
+ fcode hwSp
+ ((_,_,_,_, hwSp),_) <- getUsage
+ return hwSp)
+ return ()
\end{code}
-
-%************************************************************************
-%* *
-\subsection[CgStackery-adjust]{Adjusting the stack pointers}
-%* *
-%************************************************************************
-
-@adjustRealSpX@ generates code to alter the actual stack pointer, and
-adjusts the environment accordingly. We are careful to push the
-conditional inside the abstract C code to avoid black holes.
-ToDo: combine together?
-
-These functions {\em do not} deal with high-water-mark adjustment.
-That's done by functions which allocate stack space.
-
\begin{code}
-adjustRealSp :: VirtualSpOffset -- New offset for Arg stack ptr
- -> Code
-adjustRealSp newRealSp info_down (MkCgState absC binds
- ((vSp,fSp,realSp,hwSp), h_usage))
- = MkCgState (mkAbsCStmts absC move_instr) binds new_usage
- where
- move_instr = if (newRealSp == realSp) then AbsCNop
- else (CAssign
- (CReg Sp)
- (CAddr (spRel realSp newRealSp)))
- new_usage = ((vSp, fSp, newRealSp, hwSp), h_usage)
+setStackFrame :: VirtualSpOffset -> Code
+setStackFrame offset = do
+ ((vSp,_,fSp,realSp,hwSp), h_usage) <- getUsage
+ setUsage ((vSp, offset, fSp, realSp, hwSp), h_usage)
+
+getStackFrame :: FCode VirtualSpOffset
+getStackFrame = do
+ ((vSp,frame,fSp,realSp,hwSp), h_usage) <- getUsage
+ return frame
\end{code}
+\begin{code}
+updateFrameSize | opt_SccProfilingOn = pROF_UF_SIZE
+ | opt_GranMacros = trace ("updateFrameSize = " ++ (show gRAN_UF_SIZE))gRAN_UF_SIZE
+ | otherwise = uF_SIZE
+\end{code}
+
%************************************************************************
%* *
\subsection[CgStackery-free]{Free stack slots}
Explicitly free some stack space.
\begin{code}
+addFreeStackSlots :: [VirtualSpOffset] -> Slot -> Code
+addFreeStackSlots extra_free slot = do
+ ((vsp, frame,free, real, hw),heap_usage) <- getUsage
+ let all_free = addFreeSlots free (zip (sortLt (<) extra_free) (repeat slot))
+ let (new_vsp, new_free) = trim vsp all_free
+ let new_usage = ((new_vsp, frame, new_free, real, hw), heap_usage)
+ setUsage new_usage
+
freeStackSlots :: [VirtualSpOffset] -> Code
-freeStackSlots extra_free info_down
- state@(MkCgState abs_c binds ((vsp, free, real, hw), heap_usage))
- = MkCgState abs_c binds new_usage
- where
- new_usage = ((new_vsp, new_free, real, hw), heap_usage)
- (new_vsp, new_free) = trim vsp (addFreeSlots free extra_free)
+freeStackSlots slots = addFreeStackSlots slots Free
+
+dataStackSlots :: [VirtualSpOffset] -> Code
+dataStackSlots slots = addFreeStackSlots slots NonPointer
-addFreeSlots :: [Int] -> [Int] -> [Int]
+addFreeSlots :: [(Int,Slot)] -> [(Int,Slot)] -> [(Int,Slot)]
addFreeSlots cs [] = cs
addFreeSlots [] ns = ns
-addFreeSlots (c:cs) (n:ns)
+addFreeSlots ((c,s):cs) ((n,s'):ns)
= if c < n then
- c : addFreeSlots cs (n:ns)
+ (c,s) : addFreeSlots cs ((n,s'):ns)
else if c > n then
- n : addFreeSlots (c:cs) ns
+ (n,s') : addFreeSlots ((c,s):cs) ns
+ else if s /= s' then -- c == n
+ (c,s') : addFreeSlots cs ns
else
- panic ("addFreeSlots: equal slots: " ++ show (c:cs) ++ show (n:ns))
+ panic ("addFreeSlots: equal slots: " ++ show (c:map fst cs)
+ ++ show (n:map fst ns))
-trim :: Int{-offset-} -> [Int] -> (Int{-offset-}, [Int])
+trim :: Int{-offset-} -> [(Int,Slot)] -> (Int{-offset-}, [(Int,Slot)])
trim current_sp free_slots
- = try current_sp (reverse free_slots)
+ = try current_sp free_slots
where
- try csp [] = (csp, [])
- try csp (slot:slots)
- = if csp < slot then
- try csp slots -- Free slot off top of stk; ignore
-
- else if csp == slot then
- try (csp-1) slots -- Free slot at top of stk; trim
-
- else
- (csp, reverse (slot:slots)) -- Otherwise gap; give up
+ try csp [] = (csp,[])
+
+ try csp (slot@(off,state):slots) =
+ if state == Free && null slots' then
+ if csp' < off then
+ (csp', [])
+ else if csp' == off then
+ (csp'-1, [])
+ else
+ (csp',[slot])
+ else
+ (csp', slot:slots')
+ where
+ (csp',slots') = try csp slots
\end{code}
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