2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[CostCentre]{The @CostCentre@ data type}
8 CostCentre(..), CcName, IsDupdCC(..), IsCafCC(..),
9 -- All abstract except to friend: ParseIface.y
13 noCCS, subsumedCCS, currentCCS, overheadCCS, dontCareCCS,
14 noCostCentre, noCCAttached,
15 noCCSAttached, isCurrentCCS, isSubsumedCCS, currentOrSubsumedCCS,
16 isDerivedFromCurrentCCS, maybeSingletonCCS,
19 mkUserCC, mkAutoCC, mkAllCafsCC,
20 mkSingletonCCS, dupifyCC, pushCCOnCCS,
29 cmpCostCentre -- used for removing dups in a list
32 #include "HsVersions.h"
36 import Module ( Module )
40 import Util ( thenCmp )
43 A Cost Centre Stack is something that can be attached to a closure.
46 - the current cost centre stack (CCCS)
47 - a pre-defined cost centre stack (there are several
48 pre-defined CCSs, see below).
54 | CurrentCCS -- Pinned on a let(rec)-bound
55 -- thunk/function/constructor, this says that the
56 -- cost centre to be attached to the object, when it
57 -- is allocated, is whatever is in the
58 -- current-cost-centre-stack register.
60 | SubsumedCCS -- Cost centre stack for top-level subsumed functions
61 -- (CAFs get an AllCafsCC).
62 -- Its execution costs get subsumed into the caller.
63 -- This guy is *only* ever pinned on static closures,
64 -- and is *never* the cost centre for an SCC construct.
66 | OverheadCCS -- We charge costs due to the profiling-system
67 -- doing its work to "overhead".
69 -- Objects whose CCS is "Overhead"
70 -- have their *allocation* charged to "overhead",
71 -- but have the current CCS put into the object
74 -- For example, if we transform "f g" to "let
75 -- g' = g in f g'" (so that something about
76 -- profiling works better...), then we charge
77 -- the *allocation* of g' to OverheadCCS, but
78 -- we put the cost-centre of the call to f
79 -- (i.e., current CCS) into the g' object. When
80 -- g' is entered, the CCS of the call
83 | DontCareCCS -- We need a CCS to stick in static closures
84 -- (for data), but we *don't* expect them to
85 -- accumulate any costs. But we still need
86 -- the placeholder. This CCS is it.
88 | PushCC CostCentre CostCentreStack
89 -- These are used during code generation as the CCSs
90 -- attached to closures. A PushCC never appears as
91 -- the argument to an _scc_.
93 -- The tail (2nd argument) is either NoCCS, indicating
94 -- a staticly allocated CCS, or CurrentCCS indicating
95 -- a dynamically created CCS. We only support
96 -- statically allocated *singleton* CCSs at the
97 -- moment, for the purposes of initialising the CCS
100 deriving (Eq, Ord) -- needed for Ord on CLabel
103 A Cost Centre is the argument of an _scc_ expression.
107 = NoCostCentre -- Having this constructor avoids having
108 -- to use "Maybe CostCentre" all the time.
111 cc_name :: CcName, -- Name of the cost centre itself
112 cc_mod :: Module, -- Name of module defining this CC.
113 cc_is_dupd :: IsDupdCC, -- see below
114 cc_is_caf :: IsCafCC -- see below
118 cc_mod :: Module -- Name of module defining this CC.
121 type CcName = FastString
124 = OriginalCC -- This says how the CC is *used*. Saying that
125 | DupdCC -- it is DupdCC doesn't make it a different
126 -- CC, just that it a sub-expression which has
127 -- been moved ("dupd") into a different scope.
129 -- The point about a dupd SCC is that we don't
130 -- count entries to it, because it's not the
133 -- In the papers, it's called "SCCsub",
134 -- i.e. SCCsub CC == SCC DupdCC,
135 -- but we are trying to avoid confusion between
136 -- "subd" and "subsumed". So we call the former
139 data IsCafCC = CafCC | NotCafCC
141 -- synonym for triple which describes the cost centre info in the generated
142 -- code for a module.
144 = ( [CostCentre] -- local cost-centres that need to be decl'd
145 , [CostCentre] -- "extern" cost-centres
146 , [CostCentreStack] -- pre-defined "singleton" cost centre stacks
150 WILL: Would there be any merit to recording ``I am now using a
151 cost-centre from another module''? I don't know if this would help a
152 user; it might be interesting to us to know how much computation is
153 being moved across module boundaries.
155 SIMON: Maybe later...
160 subsumedCCS = SubsumedCCS
161 currentCCS = CurrentCCS
162 overheadCCS = OverheadCCS
163 dontCareCCS = DontCareCCS
165 noCostCentre = NoCostCentre
168 Predicates on Cost-Centre Stacks
171 noCCSAttached NoCCS = True
172 noCCSAttached _ = False
174 noCCAttached NoCostCentre = True
175 noCCAttached _ = False
177 isCurrentCCS CurrentCCS = True
178 isCurrentCCS _ = False
180 isSubsumedCCS SubsumedCCS = True
181 isSubsumedCCS _ = False
183 isCafCCS (PushCC cc NoCCS) = isCafCC cc
186 isDerivedFromCurrentCCS CurrentCCS = True
187 isDerivedFromCurrentCCS (PushCC _ ccs) = isDerivedFromCurrentCCS ccs
188 isDerivedFromCurrentCCS _ = False
190 currentOrSubsumedCCS SubsumedCCS = True
191 currentOrSubsumedCCS CurrentCCS = True
192 currentOrSubsumedCCS _ = False
194 maybeSingletonCCS (PushCC cc NoCCS) = Just cc
195 maybeSingletonCCS _ = Nothing
198 Building cost centres
201 mkUserCC :: FastString -> Module -> CostCentre
203 = NormalCC { cc_name = cc_name, cc_mod = mod,
204 cc_is_dupd = OriginalCC, cc_is_caf = NotCafCC {-might be changed-}
207 mkAutoCC :: Id -> Module -> IsCafCC -> CostCentre
208 mkAutoCC id mod is_caf
209 = NormalCC { cc_name = str, cc_mod = mod,
210 cc_is_dupd = OriginalCC, cc_is_caf = is_caf
214 -- beware: we might be making an auto CC for a compiler-generated
215 -- thing (like a CAF when -caf-all is on), so include the uniq.
216 -- See bug #249, tests prof001, prof002
217 str | isSystemName name = mkFastString (showSDoc (ppr name))
218 | otherwise = occNameFS (getOccName id)
220 mkAllCafsCC m = AllCafsCC { cc_mod = m }
224 mkSingletonCCS :: CostCentre -> CostCentreStack
225 mkSingletonCCS cc = pushCCOnCCS cc NoCCS
227 pushCCOnCCS :: CostCentre -> CostCentreStack -> CostCentreStack
230 dupifyCC cc = cc {cc_is_dupd = DupdCC}
232 isCafCC, isDupdCC :: CostCentre -> Bool
234 isCafCC (AllCafsCC {}) = True
235 isCafCC (NormalCC {cc_is_caf = CafCC}) = True
238 isDupdCC (NormalCC {cc_is_dupd = DupdCC}) = True
241 isSccCountCostCentre :: CostCentre -> Bool
242 -- Is this a cost-centre which records scc counts
245 isSccCountCostCentre NoCostCentre = panic "isSccCount:NoCostCentre"
247 isSccCountCostCentre cc | isCafCC cc = False
248 | isDupdCC cc = False
251 sccAbleCostCentre :: CostCentre -> Bool
252 -- Is this a cost-centre which can be sccd ?
255 sccAbleCostCentre NoCostCentre = panic "sccAbleCC:NoCostCentre"
257 sccAbleCostCentre cc | isCafCC cc = False
260 ccFromThisModule :: CostCentre -> Module -> Bool
261 ccFromThisModule cc m = cc_mod cc == m
265 instance Eq CostCentre where
266 c1 == c2 = case c1 `cmpCostCentre` c2 of { EQ -> True; _ -> False }
268 instance Ord CostCentre where
269 compare = cmpCostCentre
271 cmpCostCentre :: CostCentre -> CostCentre -> Ordering
273 cmpCostCentre (AllCafsCC {cc_mod = m1}) (AllCafsCC {cc_mod = m2}) = m1 `compare` m2
275 cmpCostCentre (NormalCC {cc_name = n1, cc_mod = m1, cc_is_caf = c1})
276 (NormalCC {cc_name = n2, cc_mod = m2, cc_is_caf = c2})
277 -- first key is module name, then we use "kinds" (which include
278 -- names) and finally the caf flag
279 = (m1 `compare` m2) `thenCmp` (n1 `compare` n2) `thenCmp` (c1 `cmp_caf` c2)
281 cmpCostCentre other_1 other_2
283 tag1 = tag_CC other_1
284 tag2 = tag_CC other_2
286 if tag1 <# tag2 then LT else GT
288 tag_CC (NormalCC {}) = (_ILIT 1 :: FastInt)
289 tag_CC (AllCafsCC {}) = _ILIT 2
291 cmp_caf NotCafCC CafCC = LT
292 cmp_caf NotCafCC NotCafCC = EQ
293 cmp_caf CafCC CafCC = EQ
294 cmp_caf CafCC NotCafCC = GT
296 decomposeCCS :: CostCentreStack -> ([CostCentre],CostCentreStack)
297 decomposeCCS (PushCC cc ccs) = (cc:more, ccs')
298 where (more,ccs') = decomposeCCS ccs
299 decomposeCCS ccs = ([],ccs)
302 -----------------------------------------------------------------------------
303 Printing Cost Centre Stacks.
305 The outputable instance for CostCentreStack prints the CCS as a C
308 NOTE: Not all cost centres are suitable for using in a static
309 initializer. In particular, the PushCC forms where the tail is CCCS
310 may only be used in inline C code because they expand to a
311 non-constant C expression.
314 instance Outputable CostCentreStack where
315 ppr NoCCS = ptext SLIT("NO_CCS")
316 ppr CurrentCCS = ptext SLIT("CCCS")
317 ppr OverheadCCS = ptext SLIT("CCS_OVERHEAD")
318 ppr DontCareCCS = ptext SLIT("CCS_DONT_CARE")
319 ppr SubsumedCCS = ptext SLIT("CCS_SUBSUMED")
320 ppr (PushCC cc NoCCS) = ppr cc <> ptext SLIT("_ccs")
321 ppr (PushCC cc ccs) = ptext SLIT("PushCostCentre") <>
322 parens (ppr ccs <> comma <>
323 parens(ptext SLIT("void *")) <> ppr cc)
326 -----------------------------------------------------------------------------
327 Printing Cost Centres.
329 There are several different ways in which we might want to print a
332 - the name of the cost centre, for profiling output (a C string)
333 - the label, i.e. C label for cost centre in .hc file.
334 - the debugging name, for output in -ddump things
335 - the interface name, for printing in _scc_ exprs in iface files.
337 The last 3 are derived from costCentreStr below. The first is given
341 instance Outputable CostCentre where
342 ppr cc = getPprStyle $ \ sty ->
344 then ppCostCentreLbl cc
345 else text (costCentreUserName cc)
347 -- Printing in an interface file or in Core generally
348 pprCostCentreCore (AllCafsCC {cc_mod = m})
349 = text "__sccC" <+> braces (ppr m)
350 pprCostCentreCore (NormalCC {cc_name = n, cc_mod = m,
351 cc_is_caf = caf, cc_is_dupd = dup})
352 = text "__scc" <+> braces (hsep [
359 pp_dup DupdCC = char '!'
362 pp_caf CafCC = text "__C"
365 -- Printing as a C label
366 ppCostCentreLbl (NoCostCentre) = text "NONE_cc"
367 ppCostCentreLbl (AllCafsCC {cc_mod = m}) = ppr m <> text "_CAFs_cc"
368 ppCostCentreLbl (NormalCC {cc_name = n, cc_mod = m, cc_is_caf = is_caf})
369 = ppr m <> char '_' <> ftext (zEncodeFS n) <>
370 text (case is_caf of { CafCC -> "_CAF"; _ -> "" }) <> text "_cc"
372 -- This is the name to go in the user-displayed string,
373 -- recorded in the cost centre declaration
374 costCentreUserName (NoCostCentre) = "NO_CC"
375 costCentreUserName (AllCafsCC {}) = "CAF"
376 costCentreUserName cc@(NormalCC {cc_name = name, cc_is_caf = is_caf})
377 = case is_caf of { CafCC -> "CAF:"; _ -> "" } ++ unpackFS name